syntactic - Page 4 - Developer IT

IUsable: controlling resources in a better way than IDisposable

- by Ilya Ryzhenkov

I wish we have "Usable" pattern in C#, when code block of using construct would be passed to a function as delegate: class Usable : IUsable { public void Use(Action action) // implements IUsable { // acquire resources action(); // release resources } } and in user code: using (new Usable()) { // this code block is converted to delegate and passed to Use method above } Pros: Controlled execution, exceptions The fact of using "Usable" is visible in call stack Cons: Cost of delegate Do you think it is feasible and useful, and if it doesn't have any problems from the language point of view? Are there any pitfalls you can see? EDIT: David Schmitt proposed the following using(new Usable(delegate() { // actions here }) {} It can work in the sample scenario like that, but usually you have resource already allocated and want it to look like this: using (Repository.GlobalResource) { // actions here } Where GlobalResource (yes, I know global resources are bad) implements IUsable. You can rewrite is as short as Repository.GlobalResource.Use(() => { // actions here }); But it looks a little bit weird (and more weird if you implement interface explicitly), and this is so often case in various flavours, that I thought it deserve to be new syntactic sugar in a language.

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Using ScriptingBridge framework for communicating with Entourage

- by Subramanian Ganapathy

Hi, The motivation for my question is the following doc, which describes how mail.app could be integrated using ScriptingBridge: http://developer.apple.com/mac/library/samplecode/SBSendEmail/Introduction/Intro.html I tried to apply a similar technique with Entourage as well but could not get any results so far. I understand that using AppleScript would help me solve my problem and mactech.com has extensive documentation for doing so. But i find this ScriptingBridge technique elegant and want to figure why it is not working for me with Entourage. The biggest problem seems to be my inability to create Scripting classes based on their names as it happens in Mail because Entourage has a different interface than Mail as their headers indicate. Could someone please tell me what I am missing or provide any sort of hint on why this wont work? I am also adding sample code ` MicrosoftEntourageApplication * mail = [SBApplication applicationWithBundleIdentifier:@"com.Microsoft.Entourage"]; MicrosoftEntourageOutgoingEmailMessage * emailMessage = [[[mail classForScriptingClass:@"outgoing message"] alloc] initWithProperties: [NSDictionary dictionaryWithObjectsAndKeys: @"my sample subject", @"subject", @"my sample body", @"content", nil]]; //then i create a set of recipients and try to use "to recipient" as the string scripting class id, but MicrosoftEntourageRecipient is returned as nil MicrosoftEntourageRecipient * theRecipient = [[[mail classForScriptingClass:@"to recipient"] alloc] initWithProperties: [NSDictionary dictionaryWithObjectsAndKeys: @"[email protected]", @"address", nil]]; ` I am trying to make the simple thing work, I am not even concentrating on the task I am supposed to do now. I am a Cocoa beginner( and willing to learn ), please excuse an syntactic naivetes and do point them out in the sample code, in addition to answering my question. Best Regards, Subramanian

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Using JavaCC to infer semantics from a Composite tree

- by Skice

Hi all, I am programming (in Java) a very limited symbolic calculus library that manages polynomials, exponentials and expolinomials (sums of elements like "x^n * e^(c x)"). I want the library to be extensible in the sense of new analytic forms (trigonometric, etc.) or new kinds of operations (logarithm, domain transformations, etc.), so a Composite pattern that represent the syntactic structure of an expression, together with a bunch of Visitors for the operations, does the job quite well. My problem arise when I try to implement operations that depends on the semantics more than on the syntax of the Expression (like integrals, for instance: there are a lot of resolution methods for specific classes of functions, but these same classes can be represented with more than a single syntax). So I thought I need something to "parse" the Composite tree to infer its semantics in order to invoke the right integration method (if any). Someone pointed me to JavaCC, but all the examples I've seen deal only with string parsing; so, I don't know if I'm digging in the right direction. Some suggestions? (I hope to have been clear enough!)

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Unit testing that an event is raised in C#, using reflection

- by Thomas

I want to test that setting a certain property (or more generally, executing some code) raises a certain event on my object. In that respect my problem is similar to http://stackoverflow.com/questions/248989/unit-testing-that-an-event-is-raised-in-c, but I need a lot of these tests and I hate boilerplate. So I'm looking for a more general solution, using reflection. Ideally, I would like to do something like this: [TestMethod] public void TestWidth() { MyClass myObject = new MyClass(); AssertRaisesEvent(() => { myObject.Width = 42; }, myObject, "WidthChanged"); } For the implementation of the AssertRaisesEvent, I've come this far: private void AssertRaisesEvent(Action action, object obj, string eventName) { EventInfo eventInfo = obj.GetType().GetEvent(eventName); int raisedCount = 0; Action incrementer = () => { ++raisedCount; }; Delegate handler = /* what goes here? */; eventInfo.AddEventHandler(obj, handler); action.Invoke(); eventInfo.RemoveEventHandler(obj, handler); Assert.AreEqual(1, raisedCount); } As you can see, my problem lies in creating a Delegate of the appropriate type for this event. The delegate should do nothing except invoke incrementer. Because of all the syntactic syrup in C#, my notion of how delegates and events really work is a bit hazy. How to do this?

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Theory: "Lexical Encoding"

- by _ande_turner_

I am using the term "Lexical Encoding" for my lack of a better one. A Word is arguably the fundamental unit of communication as opposed to a Letter. Unicode tries to assign a numeric value to each Letter of all known Alphabets. What is a Letter to one language, is a Glyph to another. Unicode 5.1 assigns more than 100,000 values to these Glyphs currently. Out of the approximately 180,000 Words being used in Modern English, it is said that with a vocabulary of about 2,000 Words, you should be able to converse in general terms. A "Lexical Encoding" would encode each Word not each Letter, and encapsulate them within a Sentence. // An simplified example of a "Lexical Encoding" String sentence = "How are you today?"; int[] sentence = { 93, 22, 14, 330, QUERY }; In this example each Token in the String was encoded as an Integer. The Encoding Scheme here simply assigned an int value based on generalised statistical ranking of word usage, and assigned a constant to the question mark. Ultimately, a Word has both a Spelling & Meaning though. Any "Lexical Encoding" would preserve the meaning and intent of the Sentence as a whole, and not be language specific. An English sentence would be encoded into "...language-neutral atomic elements of meaning ..." which could then be reconstituted into any language with a structured Syntactic Form and Grammatical Structure. What are other examples of "Lexical Encoding" techniques? If you were interested in where the word-usage statistics come from : http://www.wordcount.org

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Raw types and subtyping

- by Dmitrii

We have generic class SomeClass<T>{ } We can write the line: SomeClass s= new SomeClass<String>(); It's ok, because raw type is supertype for generic type. But SomeClass<String> s= new SomeClass(); is correct to. Why is it correct? I thought that type erasure was before type checking, but it's wrong. From Hacker's Guide to Javac When the Java compiler is invoked with default compile policy it performs the following passes: parse: Reads a set of *.java source files and maps the resulting token sequence into AST-Nodes. enter: Enters symbols for the definitions into the symbol table. process annotations: If Requested, processes annotations found in the specified compilation units. attribute: Attributes the Syntax trees. This step includes name resolution, type checking and constant folding. flow: Performs data ow analysis on the trees from the previous step. This includes checks for assignments and reachability. desugar: Rewrites the AST and translates away some syntactic sugar. generate: Generates Source Files or Class Files. Generic is syntax sugar, hence type erasure invoked at 6 pass, after type checking, which invoked at 4 pass. I'm confused.

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How to convert many thousands of lines of VBScript to C#?

- by Ross Patterson

I have a collection of about 10,000 small VBScript programs (50-100 lines each) and a small collection of larger ones, and I'm looking for a way to convert them to C# without resorting to by-hand transliteration. The programs are automated test cases for a web application, written for HP/Mercury's QuickTest Pro, and I'm trying to turn them into test cases for Selenium. Luckily, the tests appear to be well-written, using a library of building blocks and idioms (the larger programs), so the test cases actually resemble a domain-specific language more than they do VBScript, and the QTP-ness is well-buried inside the libraries. Ideally, what I'm searching for is a tool that can do the syntactic transformation from VBScript to C# for both the dsl-ish test cases and also the more complicated building-block libraries. That would leave me with a manual cleanup of the libraries, and probably very little work on the test cases. If I could find a VBScript-to-VB.NET translator, I'd take that also, as I suspect I could compile the VB.NET and then de-compile to C# using .NET Relector or something similar. Plan B is to write a translator of my own for the test cases, since they're in a very straight-line style, but it wouldn't help with the libraries. Any suyggestions? I haven't written a compiler in at least 15 years, and while I haven't forgotten how, I'm not looking forward to it - least of all for VBScript!

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MySQL developer here -- Nesting with select * finicky in Oracle 10g?

- by John Sullivan

I'm writing a simple diagnostic query then attempting to execute it in the Oracle 10g SQL Scratchpad. EDIT: It will not be used in code. I'm nesting a simple "Select *" and it's giving me errors. In the SQL Scratchpad for Oracle 10g Enterprise Manager Console, this statement runs fine. SELECT * FROM v$session sess, v$sql sql WHERE sql.sql_id(+) = sess.sql_id and sql.sql_text <> ' ' If I try to wrap that up in Select * from () tb2 I get an error, "ORA-00918: Column Ambiguously Defined". I didn't think that could ever happen with this kind of statement so I am a bit confused. select * from (SELECT * FROM v$session sess, v$sql sql WHERE sql.sql_id(+) = sess.sql_id and sql.sql_text <> ' ') tb2 You should always be able to select * from the result set of another select * statement using this structure as far as I'm aware... right? Is Oracle/10g/the scratchpad trying to force me to accept a certain syntactic structure to prevent excessive nesting? Is this a bug in scratchpad or something about how oracle works?

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Why isn't our c# graphics code working any more?

- by Jared

Here's the situation: We have some generic graphics code that we use for one of our projects. After doing some clean-up of the code, it seems like something isn't working anymore (The graphics output looks completely wrong). I ran a diff against the last version of the code that gave the correct output, and it looks like we changed one of our functions as follows: static public Rectangle FitRectangleOld(Rectangle rect, Size targetSize) { if (rect.Width <= 0 || rect.Height <= 0) { rect.Width = targetSize.Width; rect.Height = targetSize.Height; } else if (targetSize.Width * rect.Height > rect.Width * targetSize.Height) { rect.Width = rect.Width * targetSize.Height / rect.Height; rect.Height = targetSize.Height; } else { rect.Height = rect.Height * targetSize.Width / rect.Width; rect.Width = targetSize.Width; } return rect; } to static public Rectangle FitRectangle(Rectangle rect, Size targetSize) { if (rect.Width <= 0 || rect.Height <= 0) { rect.Width = targetSize.Width; rect.Height = targetSize.Height; } else if (targetSize.Width * rect.Height > rect.Width * targetSize.Height) { rect.Width *= targetSize.Height / rect.Height; rect.Height = targetSize.Height; } else { rect.Height *= targetSize.Width / rect.Width; rect.Width = targetSize.Width; } return rect; } All of our unit tests are all passing, and nothing in the code has changed except for some syntactic shortcuts. But like I said, the output is wrong. We'll probably just revert back to the old code, but I'm curious if anyone has any idea what's going on here. Thanks.

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SQL developer here -- Nesting with select * finicky in Oracle 10g?

- by John Sullivan

I am writing a simple diagnostic query I will execute in my Oracle 10g scratchpad. I am trying to do this as part of a step to build the query. In the SQL Scratchpad for Oracle 10g Enterprise Manager Console, this statement runs fine. SELECT * FROM v$session sess, v$sql sql WHERE sql.sql_id(+) = sess.sql_id and sql.sql_text <> ' ' If I try to wrap that up in Select * from () tb2 I get an error, "ORA-00918: Column Ambiguously Defined". I didn't think that could ever happen with this kind of statement so I am a bit confused. select * from (SELECT * FROM v$session sess, v$sql sql WHERE sql.sql_id(+) = sess.sql_id and sql.sql_text <> ' ') tb2 You should always be able to select * from the result set of another select * statement using this structure as far as I'm aware... right? Is Oracle/10g/the scratchpad trying to force me to accept a certain syntactic structure to prevent excessive nesting? Is this a bug in scratchpad or something about how oracle works?

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Windows in StreamInsight: Hopping vs. Snapshot

- by Roman Schindlauer

Three weeks ago, we explained the basic concept of windows in StreamInsight: defining sets of events that serve as arguments for set-based operations, like aggregations. Today, we want to discuss the so-called Hopping Windows and compare them with Snapshot Windows. We will compare these two, because they can serve similar purposes with different behaviors; we will discuss the remaining window type, Count Windows, another time. Hopping (and its syntactic-sugar-sister Tumbling) windows are probably the most straightforward windowing concept in StreamInsight. A hopping window is defined by its length, and the offset from one window to the next. They are aligned with some absolute point on the timeline (which can also be given as a parameter to the window) and create sets of events. The diagram below shows an example of a hopping window with length of 1h and hop size (the offset) of 15 minutes, hence creating overlapping windows: Two aspects in this diagram are important: Since this window is overlapping, an event can fall into more than one windows. If an (interval) event spans a window boundary, its lifetime will be clipped to the window, before it is passed to the set-based operation. That’s the default and currently only available window input policy. (This should only concern you if you are using a time-sensitive user-defined aggregate or operator.) The set-based operation will be applied to each of these sets, yielding a result. This result is: A single scalar value in case of built-in or user-defined aggregates. A subset of the input payloads, in case of the TopK operator. Arbitrary events, when using a user-defined operator. The timestamps of the result are almost always the ones of the windows. Only the user-defined operator can create new events with timestamps. (However, even these event lifetimes are subject to the window’s output policy, which is currently always to clip to the window end.) Let’s assume we were calculating the sum over some payload field: var result = from window in source.HoppingWindow( TimeSpan.FromHours(1), TimeSpan.FromMinutes(15), HoppingWindowOutputPolicy.ClipToWindowEnd) select new { avg = window.Avg(e => e.Value) }; Now each window is reflected by one result event: As you can see, the window definition defines the output frequency. No matter how many or few events we got from the input, this hopping window will produce one result every 15 minutes – except for those windows that do not contain any events at all, because StreamInsight window operations are empty-preserving (more about that another time). The “forced” output for every window can become a performance issue if you have a real-time query with many events in a wide group & apply – let me explain: imagine you have a lot of events that you group by and then aggregate within each group – classical streaming pattern. The hopping window produces a result in each group at exactly the same point in time for all groups, since the window boundaries are aligned with the timeline, not with the event timestamps. This means that the query output will become very bursty, delivering the results of all the groups at the same point in time. This becomes especially obvious if the events are long-lasting, spanning multiple windows each, so that the produced result events do not change their value very often. In such a case, a snapshot window can remedy. Snapshot windows are more difficult to explain than hopping windows: they represent those periods in time, when no event changes occur. In other words, if you mark all event start and and times on your timeline, then you are looking at all snapshot window boundaries: If your events are never overlapping, the snapshot window will not make much sense. It is commonly used together with timestamp modification, which make it a very powerful tool. Or as Allan Mitchell expressed in in a recent tweet: “I used to look at SnapshotWindow() with disdain. Now she is my mistress, the one I turn to in times of trouble and need”. Let’s look at a simple example: I want to compute the average of some value in my events over the last minute. I don’t want this output be produced at fixed intervals, but at soon as it changes (that’s the true event-driven spirit!). The snapshot window will include all currently active event at each point in time, hence we need to extend our original events’ lifetimes into the future: Applying the Snapshot window on these events, it will appear to be “looking back into the past”: If you look at the result produced in this diagram, you can easily prove that, at each point in time, the current event value represents the average of all original input event within the last minute. Here is the LINQ representation of that query, applying the lifetime extension before the snapshot window: var result = from window in source .AlterEventDuration(e => TimeSpan.FromMinutes(1)) .SnapshotWindow(SnapshotWindowOutputPolicy.Clip) select new { avg = window.Avg(e => e.Value) }; With more complex modifications of the event lifetimes you can achieve many more query patterns. For instance “running totals” by keeping the event start times, but snapping their end times to some fixed time, like the end of the day. Each snapshot then “sees” all events that have happened in the respective time period so far. Regards, The StreamInsight Team

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Do You Really Know Your Programming Languages?

- by Kristopher Johnson

I am often amazed at how little some of my colleagues know or care about their craft. Something that constantly frustrates me is that people don't want to learn any more than they need to about the programming languages they use every day. Many programmers seem content to learn some pidgin sub-dialect, and stick with that. If they see a keyword or construct that they aren't familiar with, they'll complain that the code is "tricky." What would you think of a civil engineer who shied away from calculus because it had "all those tricky math symbols?" I'm not suggesting that we all need to become "language lawyers." But if you make your living as a programmer, and claim to be a competent user of language X, then I think at a minimum you should know the following: Do you know the keywords of the language and what they do? What are the valid syntactic forms? How are memory, files, and other operating system resources managed? Where is the official language specification and library reference for the language? The last one is the one that really gets me. Many programmers seem to have no idea that there is a "specification" or "standard" for any particular language. I still talk to people who think that Microsoft invented C++, and that if a program doesn't compile under VC6, it's not a valid C++ program. Programmers these days have it easy when it comes to obtaining specs. Newer languages like C#, Java, Python, Ruby, etc. all have their documentation available for free from the vendors' web sites. Older languages and platforms often have standards controlled by standards bodies that demand payment for specs, but even that shouldn't be a deterrent: the C++ standard is available from ISO for $30 (and why am I the only person I know who has a copy?). Programming is hard enough even when you do know the language. If you don't, I don't see how you have a chance. What do the rest of you think? Am I right, or should we all be content with the typical level of programming language expertise? Update: Several great comments here. Thanks. A couple of people hit on something that I didn't think about: What really irks me is not the lack of knowledge, but the lack of curiosity and willingness to learn. It seems some people don't have any time to hone their craft, but they have plenty of time to write lots of bad code. And I don't expect people to be able to recite a list of keywords or EBNF expressions, but I do expect that when they see some code, they should have some inkling of what it does. Few people have complete knowledge of every dark corner of their language or platform, but everyone should at least know enough that when they see something unfamiliar, they will know how to get whatever additional information they need to understand it.

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How do I call a function name that is stored in a hash in Perl?

- by Ether

I'm sure this is covered in the documentation somewhere but I have been unable to find it... I'm looking for the syntactic sugar that will make it possible to call a method on a class whose name is stored in a hash (as opposed to a simple scalar): use strict; use warnings; package Foo; sub foo { print "in foo()\n" } package main; my %hash = (func => 'foo'); Foo->$hash{func}; If I copy $hash{func} into a scalar variable first, then I can call Foo->$func just fine... but what is missing to enable Foo->$hash{func} to work? (EDIT: I don't mean to do anything special by calling a method on class Foo -- this could just as easily be a blessed object (and in my actual code it is); it was just easier to write up a self-contained example using a class method.) EDIT 2: Just for completeness re the comments below, this is what I'm actually doing (this is in a library of Moose attribute sugar, created with Moose::Exporter): # adds an accessor to a sibling module sub foreignTable { my ($meta, $table, %args) = @_; my $class = 'MyApp::Dir1::Dir2::' . $table; my $dbAccessor = lcfirst $table; eval "require $class" or do { die "Can't load $class: $@" }; $meta->add_attribute( $table, is => 'ro', isa => $class, init_arg => undef, # don't allow in constructor lazy => 1, predicate => 'has_' . $table, default => sub { my $this = shift; $this->debug("in builder for $class"); ### here's the line that uses a hash value as the method name my @args = ($args{primaryKey} => $this->${\$args{primaryKey}}); push @args, ( _dbObject => $this->_dbObject->$dbAccessor ) if $args{fkRelationshipExists}; $this->debug("passing these values to $class -> new: @args"); $class->new(@args); }, ); } I've replaced the marked line above with this: my $pk_accessor = $this->meta->find_attribute_by_name($args{primaryKey})->get_read_method_ref; my @args = ($args{primaryKey} => $this->$pk_accessor); PS. I've just noticed that this same technique (using the Moose meta class to look up the coderef rather than assuming its naming convention) cannot also be used for predicates, as Class::MOP::Attribute does not have a similar get_predicate_method_ref accessor. :(

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emacs: how do I use edebug on code that is defined in a macro?

- by Cheeso

I don't even know the proper terminology for this lisp syntax, so I don't know if the words I'm using to ask the question, make sense. But the question makes sense, I'm sure. So let me just show you. cc-mode (cc-fonts.el) has things called "matchers" which are bits of code that run to decide how to fontify a region of code. That sounds simple enough, but the matcher code is in a form I don't completely understand, with babckticks and comma-atsign and just comma and so on, and furthermore it is embedded in a c-lang-defcost, which itself is a macro. And I want to run edebug on that code. Look: (c-lang-defconst c-basic-matchers-after "Font lock matchers for various things that should be fontified after generic casts and declarations are fontified. Used on level 2 and higher." t `(;; Fontify the identifiers inside enum lists. (The enum type ;; name is handled by `c-simple-decl-matchers' or ;; `c-complex-decl-matchers' below. ,@(when (c-lang-const c-brace-id-list-kwds) `((,(c-make-font-lock-search-function (concat "\\<\$" (c-make-keywords-re nil (c-lang-const c-brace-id-list-kwds)) "\$\\>" ;; Disallow various common punctuation chars that can't come ;; before the '{' of the enum list, to avoid searching too far. "[^\]\[{}();,/#=]*" "{") '((c-font-lock-declarators limit t nil) (save-match-data (goto-char (match-end 0)) (c-put-char-property (1- (point)) 'c-type 'c-decl-id-start) (c-forward-syntactic-ws)) (goto-char (match-end 0))))))) I am reading up on lisp syntax to figure out what those things are and what to call them, but aside from that, how can I run edebug on the code that follows the comment that reads ;; Fontify the identifiers inside enum lists. ? I know how to run edebug on a defun - just invoke edebug-defun within the function's definition, and off I go. Is there a corresponding thing I need to do to edebug the cc-mode matcher code forms?

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Using delegates in C# (Part 2)

- by rajbk

Part 1 of this post can be read here. We are now about to see the different syntaxes for invoking a delegate and some c# syntactic sugar which allows you to code faster. We have the following console application. 1: public delegate double Operation(double x, double y); 2: 3: public class Program 4: { 5: [STAThread] 6: static void Main(string[] args) 7: { 8: Operation op1 = new Operation(Division); 9: double result = op1.Invoke(10, 5); 10: 11: Console.WriteLine(result); 12: Console.ReadLine(); 13: } 14: 15: static double Division(double x, double y) { 16: return x / y; 17: } 18: } Line 1 defines a delegate type called Operation with input parameters (double x, double y) and a return type of double. On Line 8, we create an instance of this delegate and set the target to be a static method called Division (Line 15) On Line 9, we invoke the delegate (one entry in the invocation list). The program outputs 5 when run. The language provides shortcuts for creating a delegate and invoking it (see line 9 and 11). Line 9 is a syntactical shortcut for creating an instance of the Delegate. The C# compiler will infer on its own what the delegate type is and produces intermediate language that creates a new instance of that delegate. Line 11 uses a a syntactical shortcut for invoking the delegate by removing the Invoke method. The compiler sees the line and generates intermediate language which invokes the delegate. When this code is compiled, the generated IL will look exactly like the IL of the compiled code above. 1: public delegate double Operation(double x, double y); 2: 3: public class Program 4: { 5: [STAThread] 6: static void Main(string[] args) 7: { 8: //shortcut constructor syntax 9: Operation op1 = Division; 10: //shortcut invoke syntax 11: double result = op1(10, 2); 12: 13: Console.WriteLine(result); 14: Console.ReadLine(); 15: } 16: 17: static double Division(double x, double y) { 18: return x / y; 19: } 20: } C# 2.0 introduced Anonymous Methods. Anonymous methods avoid the need to create a separate method that contains the same signature as the delegate type. Instead you write the method body in-line. There is an interesting fact about Anonymous methods and closures which won’t be covered here. Use your favorite search engine ;-)We rewrite our code to use anonymous methods (see line 9): 1: public delegate double Operation(double x, double y); 2: 3: public class Program 4: { 5: [STAThread] 6: static void Main(string[] args) 7: { 8: //Anonymous method 9: Operation op1 = delegate(double x, double y) { 10: return x / y; 11: }; 12: double result = op1(10, 2); 13: 14: Console.WriteLine(result); 15: Console.ReadLine(); 16: } 17: 18: static double Division(double x, double y) { 19: return x / y; 20: } 21: } We could rewrite our delegate to be of a generic type like so (see line 2 and line 9). You will see why soon. 1: //Generic delegate 2: public delegate T Operation<T>(T x, T y); 3: 4: public class Program 5: { 6: [STAThread] 7: static void Main(string[] args) 8: { 9: Operation<double> op1 = delegate(double x, double y) { 10: return x / y; 11: }; 12: double result = op1(10, 2); 13: 14: Console.WriteLine(result); 15: Console.ReadLine(); 16: } 17: 18: static double Division(double x, double y) { 19: return x / y; 20: } 21: } The .NET 3.5 framework introduced a whole set of predefined delegates for us including public delegate TResult Func<T1, T2, TResult>(T1 arg1, T2 arg2); Our code can be modified to use this delegate instead of the one we declared. Our delegate declaration has been removed and line 7 has been changed to use the Func delegate type. 1: public class Program 2: { 3: [STAThread] 4: static void Main(string[] args) 5: { 6: //Func is a delegate defined in the .NET 3.5 framework 7: Func<double, double, double> op1 = delegate (double x, double y) { 8: return x / y; 9: }; 10: double result = op1(10, 2); 11: 12: Console.WriteLine(result); 13: Console.ReadLine(); 14: } 15: 16: static double Division(double x, double y) { 17: return x / y; 18: } 19: } .NET 3.5 also introduced lambda expressions. A lambda expression is an anonymous function that can contain expressions and statements, and can be used to create delegates or expression tree types. We change our code to use lambda expressions. 1: public class Program 2: { 3: [STAThread] 4: static void Main(string[] args) 5: { 6: //lambda expression 7: Func<double, double, double> op1 = (x, y) => x / y; 8: double result = op1(10, 2); 9: 10: Console.WriteLine(result); 11: Console.ReadLine(); 12: } 13: 14: static double Division(double x, double y) { 15: return x / y; 16: } 17: } C# 3.0 introduced the keyword var (implicitly typed local variable) where the type of the variable is inferred based on the type of the associated initializer expression. We can rewrite our code to use var as shown below (line 7). The implicitly typed local variable op1 is inferred to be a delegate of type Func<double, double, double> at compile time. 1: public class Program 2: { 3: [STAThread] 4: static void Main(string[] args) 5: { 6: //implicitly typed local variable 7: var op1 = (x, y) => x / y; 8: double result = op1(10, 2); 9: 10: Console.WriteLine(result); 11: Console.ReadLine(); 12: } 13: 14: static double Division(double x, double y) { 15: return x / y; 16: } 17: } You have seen how we can write code in fewer lines by using a combination of the Func delegate type, implicitly typed local variables and lambda expressions.

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How to get SQL Railroad Diagrams from MSDN BNF syntax notation.

- by Phil Factor

pre {margin-bottom:.0001pt; font-size:8.0pt; font-family:"Courier New"; margin-left: 0cm; margin-right: 0cm; margin-top: 0cm; } On SQL Server Books-On-Line, in the Transact-SQL Reference (database Engine), every SQL Statement has its syntax represented in ‘Backus–Naur Form’ notation (BNF) syntax. For a programmer in a hurry, this should be ideal because It is the only quick way to understand and appreciate all the permutations of the syntax. It is a great feature once you get your eye in. It isn’t the only way to get the information; You can, of course, reverse-engineer an understanding of the syntax from the examples, but your understanding won’t be complete, and you’ll have wasted time doing it. BNF is a good start in representing the syntax: Oracle and SQLite go one step further, and have proper railroad diagrams for their syntax, which is a far more accessible way of doing it. There are three problems with the BNF on MSDN. Firstly, it is isn’t a standard version of BNF, but an ancient fork from EBNF, inherited from Sybase. Secondly, it is excruciatingly difficult to understand, and thirdly it has a number of syntactic and semantic errors. The page describing DML triggers, for example, currently has the absurd BNF error that makes it state that all statements in the body of the trigger must be separated by commas. There are a few other detail problems too. Here is the offending syntax for a DML trigger, pasted from MSDN. Trigger on an INSERT, UPDATE, or DELETE statement to a table or view (DML Trigger) CREATE TRIGGER [ schema_name . ]trigger_name ON { table | view } [ WITH <dml_trigger_option> [ ,...n ] ] { FOR | AFTER | INSTEAD OF } { [ INSERT ] [ , ] [ UPDATE ] [ , ] [ DELETE ] } [ NOT FOR REPLICATION ] AS { sql_statement [ ; ] [ ,...n ] | EXTERNAL NAME <method specifier [ ; ] > } <dml_trigger_option> ::= [ ENCRYPTION ] [ EXECUTE AS Clause ] <method_specifier> ::= This should, of course, be /* Trigger on an INSERT, UPDATE, or DELETE statement to a table or view (DML Trigger) */ CREATE TRIGGER [ schema_name . ]trigger_name ON { table | view } [ WITH <dml_trigger_option> [ ,...n ] ] { FOR | AFTER | INSTEAD OF } { [ INSERT ] [ , ] [ UPDATE ] [ , ] [ DELETE ] } [ NOT FOR REPLICATION ] AS { {sql_statement [ ; ]} [ ...n ] | EXTERNAL NAME <method_specifier> [ ; ] } <dml_trigger_option> ::= [ ENCRYPTION ] [ EXECUTE AS CLAUSE ] <method_specifier> ::= assembly_name.class_name.method_name I’d love to tell Microsoft when I spot errors like this so they can correct them but I can’t. Obviously, there is a mechanism on MSDN to get errors corrected by using comments, but that doesn’t work for me (*Error occurred while saving your data.”), and when I report that the comment system doesn’t work to MSDN, I get no reply. I’ve been trying to create railroad diagrams for all the important SQL Server SQL statements, as good as you’d find for Oracle, and have so far published the CREATE TABLE and ALTER TABLE railroad diagrams based on the BNF. Although I’ve been aware of them, I’ve never realised until recently how many errors there are. Then, Colin Daley created a translator for the SQL Server dialect of BNF which outputs standard EBNF notation used by the W3C. The example MSDN BNF for the trigger would be rendered as … /* Trigger on an INSERT, UPDATE, or DELETE statement to a table or view (DML Trigger) */ create_trigger ::= 'CREATE TRIGGER' ( schema_name '.' ) ? trigger_name 'ON' ( table | view ) ( 'WITH' dml_trigger_option ( ',' dml_trigger_option ) * ) ? ( 'FOR' | 'AFTER' | 'INSTEAD OF' ) ( ( 'INSERT' ) ? ( ',' ) ? ( 'UPDATE' ) ? ( ',' ) ? ( 'DELETE' ) ? ) ( 'NOT FOR REPLICATION' ) ? 'AS' ( ( sql_statement ( ';' ) ? ) + | 'EXTERNAL NAME' method_specifier ( ';' ) ? ) dml_trigger_option ::= ( 'ENCRYPTION' ) ? ( 'EXECUTE AS CLAUSE' ) ? method_specifier ::= assembly_name '.' class_name '.' method_name Colin’s intention was to allow anyone to paste SQL Server’s BNF notation into his website-based parser, and from this generate classic railroad diagrams via Gunther Rademacher's Railroad Diagram Generator. Colin's application does this for you: you're not aware that you are moving to a different site. Because Colin's 'translator' it is a parser, it will pick up syntax errors. Once you’ve fixed the syntax errors, you will get the syntax in the form of a human-readable railroad diagram and, in this form, the semantic mistakes become flamingly obvious. Gunter’s Railroad Diagram Generator is brilliant. To be able, after correcting the MSDN dialect of BNF, to generate a standard EBNF, and from thence to create railroad diagrams for SQL Server’s syntax that are as good as Oracle’s, is a great boon, and many thanks to Colin for the idea. Here is the result of the W3C EBNF from Colin’s application then being run through the Railroad diagram generator. create_trigger: dml_trigger_option: method_specifier: Now that’s much better, you’ll agree. This is pretty easy to understand, and at this point any error is immediately obvious. This should be seriously useful, and it is to me. However there is that snag. The BNF is generally incorrect, and you can’t expect the average visitor to mess about with it. The answer is, of course, to correct the BNF on MSDN and maybe even add railroad diagrams for the syntax. Stop giggling! I agree it won’t happen. In the meantime, we need to collaboratively store and publish these corrected syntaxes ourselves as we do them. How? GitHub? SQL Server Central? Simple-Talk? What should those of us who use the system do with our corrected EBNF so that anyone can use them without hassle?

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RIF PRD: Presentation syntax issues

- by Charles Young

Over Christmas I got to play a bit with the W3C RIF PRD and came across a few issues which I thought I would record for posterity. Specifically, I was working on a grammar for the presentation syntax using a GLR grammar parser tool (I was using the current CTP of ‘M’ (MGrammer) and Intellipad – I do so hope the MS guys don’t kill off M and Intellipad now they have dropped the other parts of SQL Server Modelling). I realise that the presentation syntax is non-normative and that any issues with it do not therefore compromise the standard. However, presentation syntax is useful in its own right, and it would be great to iron out any issues in a future revision of the standard. The main issues are actually not to do with the grammar at all, but rather with the ‘running example’ in the RIF PRD recommendation. I started with the code provided in Example 9.1. There are several discrepancies when compared with the EBNF rules documented in the standard. Broadly the problems can be categorised as follows: · Parenthesis mismatch – the wrong number of parentheses are used in various places. For example, in GoldRule, the RHS of the rule (the ‘Then’) is nested in the LHS (‘the If’). In NewCustomerAndWidgetRule, the RHS is orphaned from the LHS. Together with additional incorrect parenthesis, this leads to orphanage of UnknownStatusRule from the entire Document. · Invalid use of parenthesis in ‘Forall’ constructs. Parenthesis should not be used to enclose formulae. Removal of the invalid parenthesis gave me a feeling of inconsistency when comparing formulae in Forall to formulae in If. The use of parenthesis is not actually inconsistent in these two context, but in an If construct it ‘feels’ as if you are enclosing formulae in parenthesis in a LISP-like fashion. In reality, the parenthesis is simply being used to group subordinate syntax elements. The fact that an If construct can contain only a single formula as an immediate child adds to this feeling of inconsistency. · Invalid representation of compact URIs (CURIEs) in the context of Frame productions. In several places the URIs are not qualified with a namespace prefix (‘ex1:’). This conflicts with the definition of CURIEs in the RIF Datatypes and Built-Ins 1.0 document. Here are the productions: CURIE ::= PNAME_LN | PNAME_NS PNAME_LN ::= PNAME_NS PN_LOCAL PNAME_NS ::= PN_PREFIX? ':' PN_LOCAL ::= ( PN_CHARS_U | [0-9] ) ((PN_CHARS|'.')* PN_CHARS)? PN_CHARS ::= PN_CHARS_U | '-' | [0-9] | #x00B7 | [#x0300-#x036F] | [#x203F-#x2040] PN_CHARS_U ::= PN_CHARS_BASE | '_' PN_CHARS_BASE ::= [A-Z] | [a-z] | [#x00C0-#x00D6] | [#x00D8-#x00F6] | [#x00F8-#x02FF] | [#x0370-#x037D] | [#x037F-#x1FFF] | [#x200C-#x200D] | [#x2070-#x218F] | [#x2C00-#x2FEF] | [#x3001-#xD7FF] | [#xF900-#xFDCF] | [#xFDF0-#xFFFD] | [#x10000-#xEFFFF] PN_PREFIX ::= PN_CHARS_BASE ((PN_CHARS|'.')* PN_CHARS)? The more I look at CURIEs, the more my head hurts! The RIF specification allows prefixes and colons without local names, which surprised me. However, the CURIE Syntax 1.0 working group note specifically states that this form is supported…and then promptly provides a syntactic definition that seems to preclude it! However, on (much) deeper inspection, it appears that ‘ex1:’ (for example) is allowed, but would really represent a ‘fragment’ of the ‘reference’, rather than a prefix! Ouch! This is so completely ambiguous that it surely calls into question the whole CURIE specification. In any case, RIF does not allow local names without a prefix. · Missing ‘External’ specifiers for built-in functions and predicates. The EBNF specification enforces this for terms within frames, but does not appear to enforce (what I believe is) the correct use of External on built-in predicates. In any case, the running example only specifies ‘External’ once on the predicate in UnknownStatusRule. External() is required in several other places. · The List used on the LHS of UnknownStatusRule is comma-delimited. This is not supported by the EBNF definition. Similarly, the argument list of pred:list-contains is illegally comma-delimited. · Unnecessary use of conjunction around a single formula in DiscountRule. This is strictly legal in the EBNF, but redundant. All the above issues concern the presentation syntax used in the running example. There are a few minor issues with the grammar itself. Note that Michael Kiefer stated in his paper “Rule Interchange Format: The Framework” that: “The presentation syntax of RIF … is an abstract syntax and, as such, it omits certain details that might be important for unambiguous parsing.” · The grammar cannot differentiate unambiguously between strategies and priorities on groups. A processor is forced to resolve this by detecting the use of IRIs and integers. This could easily be fixed in the grammar. · The grammar cannot unambiguously parse the ‘->’ operator in frames. Specifically, ‘-’ characters are allowed in PN_LOCAL names and hence a parser cannot determine if ‘status->’ is (‘status’ ‘->’) or (‘status-’ ‘>’). One way to fix this is to amend the PN_LOCAL production as follows: PN_LOCAL ::= ( PN_CHARS_U | [0-9] ) ((PN_CHARS|'.')* ((PN_CHARS)-('-')))? However, unilaterally changing the definition of this production, which is defined in the SPARQL Query Language for RDF specification, makes me uncomfortable. · I assume that the presentation syntax is case-sensitive. I couldn’t find this stated anywhere in the documentation, but function/predicate names do appear to be documented as being case-sensitive. · The EBNF does not specify whitespace handling. A couple of productions (RULE and ACTION_BLOCK) are crafted to enforce the use of whitespace. This is not necessary. It seems inconsistent with the rest of the specification and can cause parsing issues. In addition, the Const production exhibits whitespaces issues. The intention may have been to disallow the use of whitespace around ‘^^’, but any direct implementation of the EBNF will probably allow whitespace between ‘^^’ and the SYMSPACE. Of course, I am being a little nit-picking about all this. On the whole, the EBNF translated very smoothly and directly to ‘M’ (MGrammar) and proved to be fairly complete. I have encountered far worse issues when translating other EBNF specifications into usable grammars. I can’t imagine there would be any difficulty in implementing the same grammar in Antlr, COCO/R, gppg, XText, Bison, etc. A general observation, which repeats a point made above, is that the use of parenthesis in the presentation syntax can feel inconsistent and un-intuitive. It isn’t actually inconsistent, but I think the presentation syntax could be improved by adopting braces, rather than parenthesis, to delimit subordinate syntax elements in a similar way to so many programming languages. The familiarity of braces would communicate the structure of the syntax more clearly to people like me. If braces were adopted, parentheses could be retained around ‘var (frame | ‘new()’) constructs in action blocks. This use of parenthesis feels very LISP-like, and I think that this is my issue. It’s as if the presentation syntax represents the deformed love-child of LISP and C. In some places (specifically, action blocks), parenthesis is used in a LISP-like fashion. In other places it is used like braces in C. I find this quite confusing. Here is a corrected version of the running example (Example 9.1) in compliant presentation syntax: Document( Prefix( ex1 <http://example.com/2009/prd2> ) (* ex1:CheckoutRuleset *) Group rif:forwardChaining ( (* ex1:GoldRule *) Group 10 ( Forall ?customer such that And(?customer # ex1:Customer ?customer[ex1:status->"Silver"]) (Forall ?shoppingCart such that ?customer[ex1:shoppingCart->?shoppingCart] (If Exists ?value (And(?shoppingCart[ex1:value->?value] External(pred:numeric-greater-than-or-equal(?value 2000)))) Then Do(Modify(?customer[ex1:status->"Gold"]))))) (* ex1:DiscountRule *) Group ( Forall ?customer such that ?customer # ex1:Customer (If Or( ?customer[ex1:status->"Silver"] ?customer[ex1:status->"Gold"]) Then Do ((?s ?customer[ex1:shoppingCart-> ?s]) (?v ?s[ex1:value->?v]) Modify(?s [ex1:value->External(func:numeric-multiply (?v 0.95))])))) (* ex1:NewCustomerAndWidgetRule *) Group ( Forall ?customer such that And(?customer # ex1:Customer ?customer[ex1:status->"New"] ) (If Exists ?shoppingCart ?item (And(?customer[ex1:shoppingCart->?shoppingCart] ?shoppingCart[ex1:containsItem->?item] ?item # ex1:Widget ) ) Then Do( (?s ?customer[ex1:shoppingCart->?s]) (?val ?s[ex1:value->?val]) (?voucher ?customer[ex1:voucher->?voucher]) Retract(?customer[ex1:voucher->?voucher]) Retract(?voucher) Modify(?s[ex1:value->External(func:numeric-multiply(?val 0.90))])))) (* ex1:UnknownStatusRule *) Group ( Forall ?customer such that ?customer # ex1:Customer (If Not(Exists ?status (And(?customer[ex1:status->?status] External(pred:list-contains(List("New" "Bronze" "Silver" "Gold") ?status)) ))) Then Do( Execute(act:print(External(func:concat("New customer: " ?customer)))) Assert(?customer[ex1:status->"New"])))) ) ) I hope that helps someone out there :-)

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Pure JSP without mixing HTML, by writing html as Java-like code

- by ADTC

Please read before answering. This is a fantasy programming technique I'm dreaming up. I want to know if there's anything close in real life. The following JSP page: <% html { head { title {"Pure fantasy";} } body { h1 {"A heading with double quote (\") character";} p {"a paragraph";} String s = "a paragraph in string. the date is "; p { s; new Date().toString(); } table (Border.ZERO, new Padding(27)) { tr { for (int i = 0; i < 10; i++) { td {i;} } } } } } %> could generate the following HTML page: <html> <head> <title>Pure fantasy</title> </head> <body> <h1>A heading with double quote (") character</h1> <p>a paragraph</p> <p>a paragraph in string. the date is 11 December 2012</p> <table border="0" padding="27"> <tr> <td>0</td> <td>1</td> <td>2</td> <td>3</td> <td>4</td> <td>5</td> <td>6</td> <td>7</td> <td>8</td> <td>9</td> </tr> </table> </body> </html> The thing about this fantasy is it reuses the same old Java programming language technique that enable customized keywords used in a way similar to if-else-then, while, try-catch etc to represent html tags in a non-html way that can easily be checked for syntactic correctness, and most importantly can easily be mixed up with regular Java code without being lost in a sea of <%, %>, <%=, out.write(), etc. An added feature is that strings can directly be placed as commands to print out into generated HTML, something Java doesn't support (where pure strings have to be assigned to variables before use). Is there anything in real life that comes close? If not, is it possible to define customized keywords in Java or JSP? Or do I have to create an entirely new programming language for that? What problems do you see with this kind of setup? PS: I know you can use HTML libraries to construct HTML using Java code, but the problem with such libraries is, the source code itself doesn't have a readable HTML representation like the code above does - if you get what I mean.

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CodePlex Daily Summary for Sunday, June 12, 2011

CodePlex Daily Summary for Sunday, June 12, 2011Popular ReleasesSizeOnDisk: 1.0.8.4: Fix: Contextual menu failures. Switch to ShellExecuteEx of Win32Api.Phalanger - The PHP Language Compiler for the .NET Framework: 2.1 (June 2011) for .NET 4.0: Release of Phalanger 2.1 - the opensource PHP compiler for .NET framework 4.0. Installation package also includes basic version of Phalanger Tools for Visual Studio 2010. This allows you to easily create, build and debug Phalanger web or application inside this ultimate integrated development environment. You can even install the tools into the free Visual Studio 2010 Shell (Integrated). To improve the performance of your application using MySQL, please use Managed MySQL Extension for Phala...WPF Application Framework (WAF): WPF Application Framework (WAF) 2.0.0.7: Version: 2.0.0.7 (Milestone 7): This release contains the source code of the WPF Application Framework (WAF) and the sample applications. Requirements .NET Framework 4.0 (The package contains a solution file for Visual Studio 2010) The unit test projects require Visual Studio 2010 Professional Remark The sample applications are using Microsoft’s IoC container MEF. However, the WPF Application Framework (WAF) doesn’t force you to use the same IoC container in your application. You can use ...SimplePlanner: v2.0b: For 2011-2012 Sem 1 ???2011-2012 ????Visual Studio 2010 Help Downloader: 1.0.0.3: Domain name support for proxy Cleanup old packages bug Writing to EventLog with UAC enabled bug Small fixes & RefactoringMedia Companion: MC 3.406b weekly: With this version change a movie rebuild is required when first run -else MC will lock up on exit. Extract the entire archive to a folder which has user access rights, eg desktop, documents etc. Refer to the documentation on this site for the Installation & Setup Guide Important! If you find MC not displaying movie data properly, please try a 'movie rebuild' to reload the data from the nfo's into MC's cache. Fixes Movies Readded movie preference to rename invalid or scene nfo's to info ext...Windows Azure VM Assistant: AzureVMAssist V1.0.0.5: AzureVMAssist V1.0.0.5 (Debug) - Test Release VersionNetOffice - The easiest way to use Office in .NET: NetOffice Release 0.9: Changes: - fix examples (include issue 16026) - add new examples - 32Bit/64Bit Walkthrough is now available in technical Documentation. Includes: - Runtime Binaries and Source Code for .NET Framework:......v2.0, v3.0, v3.5, v4.0 - Tutorials in C# and VB.Net:..............................................................COM Proxy Management, Events, etc. - Examples in C# and VB.Net:............................................................Excel, Word, Outlook, PowerPoint, Access - COMAddi...Reusable Library: V1.1.3: A collection of reusable abstractions for enterprise application developerClosedXML - The easy way to OpenXML: ClosedXML 0.54.0: New on this release: 1) Mayor performance improvements. 2) AdjustToContents now take into account the text rotation. 3) Fixed issues 6782, 6784, 6788HTML-IDEx: HTML-IDEx .15 ALPHA: This release fixes line counting a little bit and adds the masshighlight() sub, which highlights pasted and inserted code.AutoLoL: AutoLoL v2.0.3: - Improved summoner spells are now displayed - Fixed some of the startup errors people got - Double clicking an item selects it - Some usability changes that make using AutoLoL just a little easier - Bug fixes AutoLoL v2 is not an update, but an entirely new version! Please install to a different directory than AutoLoL v1Host Profiles: Host Profiles 1.0: Host Profiles 1.0 Release Quickly modify host file Automatically flush dnsVidCoder: 0.9.2: Updated to HandBrake 4024svn. This fixes problems with mpeg2 sources: corrupted previews, incorrect progress indicators and encodes that incorrectly report as failed. Fixed a problem that prevented target sizes above 2048 MB.SharePoint Search XSL Samples: SharePoint 2010 Samples: I have updated some of the samples from the 2007 release. These all work in SharePoint 2010. I removed the Pivot on File Extension because SharePoint 2010 search has refiners that perform the same function.AcDown????? - Anime&Comic Downloader: AcDown????? v3.0 Beta5: ??AcDown?????????????，??????????????，????、????。?????Acfun????? ????32??64? Windows XP/Vista/7 ????????????? ??：????????Windows XP???,?????????.NET Framework 2.0???(x86)?.NET Framework 2.0???(x64)，?????"?????????"??? ??v3.0 Beta5 ?????????? ???? ?? ???????? ???"????????"?? ????????????? ????????/???? ?? ???"????"??? ?? ??????????? ?? ?? ??????????? ?? ?????????????????? ??????????????????? ???????????????? ????????????Discussions???????? ????AcDown??????????????VFPX: GoFish 4 Beta 1: Current beta is Build 144 (released 2011-06-07 ) See the GoFish4 info page for details and video link: http://vfpx.codeplex.com/wikipage?title=GoFishShowUI: Write-UI -in PowerShell: ShowUI: ShowUI is a PowerShell module to help you write rich user interfaces in script.SharePoint 2010 FBA Pack: SharePoint 2010 FBA Pack 1.0.3: Fixed User Management screen when "RequiresQuestionAndAnswer" set to true Reply to Email Address can now be customized User Management page now only displays users that reside in the membership database Web parts have been changed to inherit from System.Web.UI.WebControls.WebParts.WebPart, so that they will display on anonymous application pages For installation and configuration steps see here.Babylon Toolkit: Babylon.Toolkit v1.0.4: Note about samples: In order to run samples, you need to configure visual studio to run them as an "Out-of-browser application". in order to do that, go to the property page of a sample project, go to the Debug tab, and check the "Out-of-browser application" radio. New features : New Effects BasicEffect3Lights (3 dir lights instead of 1 position light) CartoonEffect (work in progress) SkinnedEffect (with normal and specular map support) SplattingEffect (for multi-texturing with smooth ...New ProjectsAnything Over Anything (Network Tunneling): Tunneling software created using the Reactive Extensions framework! Rx is not just for events!!!BDDocs - Behavior Driven Documentation: An alternative tool to enable project collaboration between stakeholders in a BDD environment. Focuses more on the domain and its implementation then the technical details of the testing framework.Checkin Policies for TFS 2010: More check-in policies for TFS 2010cheese: Projet d'études sur les jeux d'échecs http://davcha.wordpress.comCodeCrusade: Code Crusade is a programming game based around Lua and C#.Dimensional Values: Dimensional Values is a class library that defines units like inch, foot, meter, second, minute, hour, Newton, Pascal, Hertz, etc. that qualify values stored in classes of different dimensions such as the length dimension, the time dimension, the force dimension, etc. The library takes care of unit conversion automatically and produces higher dimension class objects from the mathematical operators (for example, dividing a length dimensional value by a time dimensional value automatically y...Enlight Adventures: Enlight Adventures is a Windows Phone 7 game that is based on the activities of the Enlight Fountain Control Group at the University of Wisconsin - Madison.Expression Tree Serializer: .NET 4.0 and Silverlight 4 class library that serializes and deserializes Expression instances. Also: a WCF IQueryable LINQ Provider and Web Http (REST) client for Silverlight that provides a simplified REST client API (i.e. WCF's WebChannelFactory) that's easier to use than WebClient.F# and C# ASP.NET MVC 3 (Razor) VSIX Project Template Example: This project provides an example of how to create a F# and C# VSIX Project Template made up of a C# ASP.NET MVC 3 web application, a F# Library that contains controllers, models, etc., and a F# Library that can be used to contain unit tests. FreeForm - SilverLight Dynamic Form Builder: FreeForm is a SilverLight4 Dynamic Forms Designer. It is enterprise forms for gathering information and making tools, include a lot of Silverlight4 interface control. Now Give Up InfoPath! TO Use FreeForm! First version online DEMO: http://crmwin.com/TestPage.html?Type=tempInternational Geek Developer Alliance: Take it easy!Kouak - HTTP File Share Server: Kouak is a basic portable file share server over http. He let you share easily files in eterogenous environements and in just few click. He don't need installation and run on every machine from windows xp s2 to windows 7.MARK: MARK is an interpreted programming language, written in PHP, for beginners to learn the fundamentals of programming paradigms. To make learning easier this language cuts the syntactic learning curve out that can hinder learning - hence allowing any beginner to learn the fundamentals of programming easily, whilst having fun with an easy-to-write, powerful programming language.Movie Manager: A tool for personal Movie CollectionNairc: This is a telescope control system project of Nairc.NPD: NPD Trading SystemObjects Library: OLib is a list of objects for programming, Programmers don't have to make alot of own classes anymoreProgressbar Field: The progress bar is typically used when an application performs tasks such as project progress or sales activity. Users of an application might consider an application non-informative if there is no visual cue.PTask: PTask is an API built on the .NET Task API that simplifies the execution in parrallel of dependent units of work. It provides a fluent API for building node dependency structures and executes those structures with the maximum level of parralelization using the thread pool.Quant: quantSharpAuctioneer: A set of classes to parse and read the World of Warcraft Auctioneer Add-On scan data.SimplePlanner: NTU Simple PlannerSiteUnity Framework: SiteUnity Framework makes it easier to build website. The target of framework, write less and simple code to build complex website. For that purpose there are some modules for viewing and managing page. It's develop in Asp.NET using C#, Mssql and Jquery.SMTP Proxy for GMail and Windows Live Mail/Hotmail: GMail and Microsoft Live Mail require encrypted connections (SSL/TLS), but not all software supports SSL/TLS. SmtpProxy accepts unencrypted connections and forwards them to GMail/Live. It runs as a Windows Service and supports ALL email clients. It's developed in C#/.NET4.WipeTouch, a jQuery plugin for touch devices: jQuery plugin for touch wipe events. Detects when user wipes on all 9 directions (top, bottom, left, right and diagonals) and triggers the desired event.

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Changes to the LINQ-to-StreamInsight Dialect

- by Roman Schindlauer

In previous versions of StreamInsight (1.0 through 2.0), CepStream<> represents temporal streams of many varieties: Streams with ‘open’ inputs (e.g., those defined and composed over CepStream<T>.Create(string streamName) Streams with ‘partially bound’ inputs (e.g., those defined and composed over CepStream<T>.Create(Type adapterFactory, …)) Streams with fully bound inputs (e.g., those defined and composed over To*Stream – sequences or DQC) The stream may be embedded (where Server.Create is used) The stream may be remote (where Server.Connect is used) When adding support for new programming primitives in StreamInsight 2.1, we faced a choice: Add a fourth variety (use CepStream<> to represent streams that are bound the new programming model constructs), or introduce a separate type that represents temporal streams in the new user model. We opted for the latter. Introducing a new type has the effect of reducing the number of (confusing) runtime failures due to inappropriate uses of CepStream<> instances in the incorrect context. The new types are: IStreamable<>, which logically represents a temporal stream. IQStreamable<> : IStreamable<>, which represents a queryable temporal stream. Its relationship to IStreamable<> is analogous to the relationship of IQueryable<> to IEnumerable<>. The developer can compose temporal queries over remote stream sources using this type. The syntax of temporal queries composed over IQStreamable<> is mostly consistent with the syntax of our existing CepStream<>-based LINQ provider. However, we have taken the opportunity to refine certain aspects of the language surface. Differences are outlined below. Because 2.1 introduces new types to represent temporal queries, the changes outlined in this post do no impact existing StreamInsight applications using the existing types! SelectMany StreamInsight does not support the SelectMany operator in its usual form (which is analogous to SQL’s “CROSS APPLY” operator): static IEnumerable<R> SelectMany<T, R>(this IEnumerable<T> source, Func<T, IEnumerable<R>> collectionSelector) It instead uses SelectMany as a convenient syntactic representation of an inner join. The parameter to the selector function is thus unavailable. Because the parameter isn’t supported, its type in StreamInsight 1.0 – 2.0 wasn’t carefully scrutinized. Unfortunately, the type chosen for the parameter is nonsensical to LINQ programmers: static CepStream<R> SelectMany<T, R>(this CepStream<T> source, Expression<Func<CepStream<T>, CepStream<R>>> streamSelector) Using Unit as the type for the parameter accurately reflects the StreamInsight’s capabilities: static IQStreamable<R> SelectMany<T, R>(this IQStreamable<T> source, Expression<Func<Unit, IQStreamable<R>>> streamSelector) For queries that succeed – that is, queries that do not reference the stream selector parameter – there is no difference between the code written for the two overloads: from x in xs from y in ys select f(x, y) Top-K The Take operator used in StreamInsight causes confusion for LINQ programmers because it is applied to the (unbounded) stream rather than the (bounded) window, suggesting that the query as a whole will return k rows: (from win in xs.SnapshotWindow() from x in win orderby x.A select x.B).Take(k) The use of SelectMany is also unfortunate in this context because it implies the availability of the window parameter within the remainder of the comprehension. The following compiles but fails at runtime: (from win in xs.SnapshotWindow() from x in win orderby x.A select win).Take(k) The Take operator in 2.1 is applied to the window rather than the stream: Before After (from win in xs.SnapshotWindow() from x in win orderby x.A select x.B).Take(k) from win in xs.SnapshotWindow() from b in (from x in win orderby x.A select x.B).Take(k) select b Multicast We are introducing an explicit multicast operator in order to preserve expression identity, which is important given the semantics about moving code to and from StreamInsight. This also better matches existing LINQ dialects, such as Reactive. This pattern enables expressing multicasting in two ways: Implicit Explicit var ys = from x in xs where x.A > 1 select x; var zs = from y1 in ys from y2 in ys.ShiftEventTime(_ => TimeSpan.FromSeconds(1)) select y1 + y2; var ys = from x in xs where x.A > 1 select x; var zs = ys.Multicast(ys1 => from y1 in ys1 from y2 in ys1.ShiftEventTime(_ => TimeSpan.FromSeconds(1)) select y1 + y2; Notice the product translates an expression using implicit multicast into an expression using the explicit multicast operator. The user does not see this translation. Default window policies Only default window policies are supported in the new surface. Other policies can be simulated by using AlterEventLifetime. Before After xs.SnapshotWindow( WindowInputPolicy.ClipToWindow, SnapshotWindowInputPolicy.Clip) xs.SnapshotWindow() xs.TumblingWindow( TimeSpan.FromSeconds(1), HoppingWindowOutputPolicy.PointAlignToWindowEnd) xs.TumblingWindow( TimeSpan.FromSeconds(1)) xs.TumblingWindow( TimeSpan.FromSeconds(1), HoppingWindowOutputPolicy.ClipToWindowEnd) Not supported … LeftAntiJoin Representation of LASJ as a correlated sub-query in the LINQ surface is problematic as the StreamInsight engine does not support correlated sub-queries (see discussion of SelectMany). The current syntax requires the introduction of an otherwise unsupported ‘IsEmpty()’ operator. As a result, the pattern is not discoverable and implies capabilities not present in the server. The direct representation of LASJ is used instead: Before After from x in xs where (from y in ys where x.A > y.B select y).IsEmpty() select x xs.LeftAntiJoin(ys, (x, y) => x.A > y.B) from x in xs where (from y in ys where x.A == y.B select y).IsEmpty() select x xs.LeftAntiJoin(ys, x => x.A, y => y.B) ApplyWithUnion The ApplyWithUnion methods have been deprecated since their signatures are redundant given the standard SelectMany overloads: Before After xs.GroupBy(x => x.A).ApplyWithUnion(gs => from win in gs.SnapshotWindow() select win.Count()) xs.GroupBy(x => x.A).SelectMany( gs => from win in gs.SnapshotWindow() select win.Count()) xs.GroupBy(x => x.A).ApplyWithUnion(gs => from win in gs.SnapshotWindow() select win.Count(), r => new { r.Key, Count = r.Payload }) from x in xs group x by x.A into gs from win in gs.SnapshotWindow() select new { gs.Key, Count = win.Count() } Alternate UDO syntax The representation of UDOs in the StreamInsight LINQ dialect confuses cardinalities. Based on the semantics of user-defined operators in StreamInsight, one would expect to construct queries in the following form: from win in xs.SnapshotWindow() from y in MyUdo(win) select y Instead, the UDO proxy method is referenced within a projection, and the (many) results returned by the user code are automatically flattened into a stream: from win in xs.SnapshotWindow() select MyUdo(win) The “many-or-one” confusion is exemplified by the following example that compiles but fails at runtime: from win in xs.SnapshotWindow() select MyUdo(win) + win.Count() The above query must fail because the UDO is in fact returning many values per window while the count aggregate is returning one. Original syntax New alternate syntax from win in xs.SnapshotWindow() select win.UdoProxy(1) from win in xs.SnapshotWindow() from y in win.UserDefinedOperator(() => new Udo(1)) select y -or- from win in xs.SnapshotWindow() from y in win.UdoMacro(1) select y Notice that this formulation also sidesteps the dynamic type pitfalls of the existing “proxy method” approach to UDOs, in which the type of the UDO implementation (TInput, TOuput) and the type of its constructor arguments (TConfig) need to align in a precise and non-obvious way with the argument and return types for the corresponding proxy method. UDSO syntax UDSO currently leverages the DataContractSerializer to clone initial state for logical instances of the user operator. Initial state will instead be described by an expression in the new LINQ surface. Before After xs.Scan(new Udso()) xs.Scan(() => new Udso()) Name changes ShiftEventTime => AlterEventStartTime: The alter event lifetime overload taking a new start time value has been renamed. CountByStartTimeWindow => CountWindow

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Changes to the LINQ-to-StreamInsight Dialect

- by Roman Schindlauer

In previous versions of StreamInsight (1.0 through 2.0), CepStream<> represents temporal streams of many varieties: Streams with ‘open’ inputs (e.g., those defined and composed over CepStream<T>.Create(string streamName) Streams with ‘partially bound’ inputs (e.g., those defined and composed over CepStream<T>.Create(Type adapterFactory, …)) Streams with fully bound inputs (e.g., those defined and composed over To*Stream – sequences or DQC) The stream may be embedded (where Server.Create is used) The stream may be remote (where Server.Connect is used) When adding support for new programming primitives in StreamInsight 2.1, we faced a choice: Add a fourth variety (use CepStream<> to represent streams that are bound the new programming model constructs), or introduce a separate type that represents temporal streams in the new user model. We opted for the latter. Introducing a new type has the effect of reducing the number of (confusing) runtime failures due to inappropriate uses of CepStream<> instances in the incorrect context. The new types are: IStreamable<>, which logically represents a temporal stream. IQStreamable<> : IStreamable<>, which represents a queryable temporal stream. Its relationship to IStreamable<> is analogous to the relationship of IQueryable<> to IEnumerable<>. The developer can compose temporal queries over remote stream sources using this type. The syntax of temporal queries composed over IQStreamable<> is mostly consistent with the syntax of our existing CepStream<>-based LINQ provider. However, we have taken the opportunity to refine certain aspects of the language surface. Differences are outlined below. Because 2.1 introduces new types to represent temporal queries, the changes outlined in this post do no impact existing StreamInsight applications using the existing types! SelectMany StreamInsight does not support the SelectMany operator in its usual form (which is analogous to SQL’s “CROSS APPLY” operator): static IEnumerable<R> SelectMany<T, R>(this IEnumerable<T> source, Func<T, IEnumerable<R>> collectionSelector) It instead uses SelectMany as a convenient syntactic representation of an inner join. The parameter to the selector function is thus unavailable. Because the parameter isn’t supported, its type in StreamInsight 1.0 – 2.0 wasn’t carefully scrutinized. Unfortunately, the type chosen for the parameter is nonsensical to LINQ programmers: static CepStream<R> SelectMany<T, R>(this CepStream<T> source, Expression<Func<CepStream<T>, CepStream<R>>> streamSelector) Using Unit as the type for the parameter accurately reflects the StreamInsight’s capabilities: static IQStreamable<R> SelectMany<T, R>(this IQStreamable<T> source, Expression<Func<Unit, IQStreamable<R>>> streamSelector) For queries that succeed – that is, queries that do not reference the stream selector parameter – there is no difference between the code written for the two overloads: from x in xs from y in ys select f(x, y) Top-K The Take operator used in StreamInsight causes confusion for LINQ programmers because it is applied to the (unbounded) stream rather than the (bounded) window, suggesting that the query as a whole will return k rows: (from win in xs.SnapshotWindow() from x in win orderby x.A select x.B).Take(k) The use of SelectMany is also unfortunate in this context because it implies the availability of the window parameter within the remainder of the comprehension. The following compiles but fails at runtime: (from win in xs.SnapshotWindow() from x in win orderby x.A select win).Take(k) The Take operator in 2.1 is applied to the window rather than the stream: Before After (from win in xs.SnapshotWindow() from x in win orderby x.A select x.B).Take(k) from win in xs.SnapshotWindow() from b in (from x in win orderby x.A select x.B).Take(k) select b Multicast We are introducing an explicit multicast operator in order to preserve expression identity, which is important given the semantics about moving code to and from StreamInsight. This also better matches existing LINQ dialects, such as Reactive. This pattern enables expressing multicasting in two ways: Implicit Explicit var ys = from x in xs where x.A > 1 select x; var zs = from y1 in ys from y2 in ys.ShiftEventTime(_ => TimeSpan.FromSeconds(1)) select y1 + y2; var ys = from x in xs where x.A > 1 select x; var zs = ys.Multicast(ys1 => from y1 in ys1 from y2 in ys1.ShiftEventTime(_ => TimeSpan.FromSeconds(1)) select y1 + y2; Notice the product translates an expression using implicit multicast into an expression using the explicit multicast operator. The user does not see this translation. Default window policies Only default window policies are supported in the new surface. Other policies can be simulated by using AlterEventLifetime. Before After xs.SnapshotWindow( WindowInputPolicy.ClipToWindow, SnapshotWindowInputPolicy.Clip) xs.SnapshotWindow() xs.TumblingWindow( TimeSpan.FromSeconds(1), HoppingWindowOutputPolicy.PointAlignToWindowEnd) xs.TumblingWindow( TimeSpan.FromSeconds(1)) xs.TumblingWindow( TimeSpan.FromSeconds(1), HoppingWindowOutputPolicy.ClipToWindowEnd) Not supported … LeftAntiJoin Representation of LASJ as a correlated sub-query in the LINQ surface is problematic as the StreamInsight engine does not support correlated sub-queries (see discussion of SelectMany). The current syntax requires the introduction of an otherwise unsupported ‘IsEmpty()’ operator. As a result, the pattern is not discoverable and implies capabilities not present in the server. The direct representation of LASJ is used instead: Before After from x in xs where (from y in ys where x.A > y.B select y).IsEmpty() select x xs.LeftAntiJoin(ys, (x, y) => x.A > y.B) from x in xs where (from y in ys where x.A == y.B select y).IsEmpty() select x xs.LeftAntiJoin(ys, x => x.A, y => y.B) ApplyWithUnion The ApplyWithUnion methods have been deprecated since their signatures are redundant given the standard SelectMany overloads: Before After xs.GroupBy(x => x.A).ApplyWithUnion(gs => from win in gs.SnapshotWindow() select win.Count()) xs.GroupBy(x => x.A).SelectMany( gs => from win in gs.SnapshotWindow() select win.Count()) xs.GroupBy(x => x.A).ApplyWithUnion(gs => from win in gs.SnapshotWindow() select win.Count(), r => new { r.Key, Count = r.Payload }) from x in xs group x by x.A into gs from win in gs.SnapshotWindow() select new { gs.Key, Count = win.Count() } Alternate UDO syntax The representation of UDOs in the StreamInsight LINQ dialect confuses cardinalities. Based on the semantics of user-defined operators in StreamInsight, one would expect to construct queries in the following form: from win in xs.SnapshotWindow() from y in MyUdo(win) select y Instead, the UDO proxy method is referenced within a projection, and the (many) results returned by the user code are automatically flattened into a stream: from win in xs.SnapshotWindow() select MyUdo(win) The “many-or-one” confusion is exemplified by the following example that compiles but fails at runtime: from win in xs.SnapshotWindow() select MyUdo(win) + win.Count() The above query must fail because the UDO is in fact returning many values per window while the count aggregate is returning one. Original syntax New alternate syntax from win in xs.SnapshotWindow() select win.UdoProxy(1) from win in xs.SnapshotWindow() from y in win.UserDefinedOperator(() => new Udo(1)) select y -or- from win in xs.SnapshotWindow() from y in win.UdoMacro(1) select y Notice that this formulation also sidesteps the dynamic type pitfalls of the existing “proxy method” approach to UDOs, in which the type of the UDO implementation (TInput, TOuput) and the type of its constructor arguments (TConfig) need to align in a precise and non-obvious way with the argument and return types for the corresponding proxy method. UDSO syntax UDSO currently leverages the DataContractSerializer to clone initial state for logical instances of the user operator. Initial state will instead be described by an expression in the new LINQ surface. Before After xs.Scan(new Udso()) xs.Scan(() => new Udso()) Name changes ShiftEventTime => AlterEventStartTime: The alter event lifetime overload taking a new start time value has been renamed. CountByStartTimeWindow => CountWindow

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Using WeakReference to resolve issue with .NET unregistered event handlers causing memory leaks.

- by Eric

The problem: Registered event handlers create a reference from the event to the event handler's instance. If that instance fails to unregister the event handler (via Dispose, presumably), then the instance memory will not be freed by the garbage collector. Example: class Foo { public event Action AnEvent; public void DoEvent() { if (AnEvent != null) AnEvent(); } } class Bar { public Bar(Foo l) { l.AnEvent += l_AnEvent; } void l_AnEvent() { } } If I instantiate a Foo, and pass this to a new Bar constructor, then let go of the Bar object, it will not be freed by the garbage collector because of the AnEvent registration. I consider this a memory leak, and seems just like my old C++ days. I can, of course, make Bar IDisposable, unregister the event in the Dispose() method, and make sure to call Dispose() on instances of it, but why should I have to do this? I first question why events are implemented with strong references? Why not use weak references? An event is used to abstractly notify an object of changes in another object. It seems to me that if the event handler's instance is no longer in use (i.e., there are no non-event references to the object), then any events that it is registered with should automatically be unregistered. What am I missing? I have looked at WeakEventManager. Wow, what a pain. Not only is it very difficult to use, but its documentation is inadequate (see http://msdn.microsoft.com/en-us/library/system.windows.weakeventmanager.aspx -- noticing the "Notes to Inheritors" section that has 6 vaguely described bullets). I have seen other discussions in various places, but nothing I felt I could use. I propose a simpler solution based on WeakReference, as described here. My question is: Does this not meet the requirements with significantly less complexity? To use the solution, the above code is modified as follows: class Foo { public WeakReferenceEvent AnEvent = new WeakReferenceEvent(); internal void DoEvent() { AnEvent.Invoke(); } } class Bar { public Bar(Foo l) { l.AnEvent += l_AnEvent; } void l_AnEvent() { } } Notice two things: 1. The Foo class is modified in two ways: The event is replaced with an instance of WeakReferenceEvent, shown below; and the invocation of the event is changed. 2. The Bar class is UNCHANGED. No need to subclass WeakEventManager, implement IWeakEventListener, etc. OK, so on to the implementation of WeakReferenceEvent. This is shown here. Note that it uses the generic WeakReference that I borrowed from here: http://damieng.com/blog/2006/08/01/implementingweakreferencet I had to add Equals() and GetHashCode() to his class, which I include below for reference. class WeakReferenceEvent { public static WeakReferenceEvent operator +(WeakReferenceEvent wre, Action handler) { wre._delegates.Add(new WeakReference<Action>(handler)); return wre; } public static WeakReferenceEvent operator -(WeakReferenceEvent wre, Action handler) { foreach (var del in wre._delegates) if (del.Target == handler) { wre._delegates.Remove(del); return wre; } return wre; } HashSet<WeakReference<Action>> _delegates = new HashSet<WeakReference<Action>>(); internal void Invoke() { HashSet<WeakReference<Action>> toRemove = null; foreach (var del in _delegates) { if (del.IsAlive) del.Target(); else { if (toRemove == null) toRemove = new HashSet<WeakReference<Action>>(); toRemove.Add(del); } } if (toRemove != null) foreach (var del in toRemove) _delegates.Remove(del); } } public class WeakReference<T> : IDisposable { private GCHandle handle; private bool trackResurrection; public WeakReference(T target) : this(target, false) { } public WeakReference(T target, bool trackResurrection) { this.trackResurrection = trackResurrection; this.Target = target; } ~WeakReference() { Dispose(); } public void Dispose() { handle.Free(); GC.SuppressFinalize(this); } public virtual bool IsAlive { get { return (handle.Target != null); } } public virtual bool TrackResurrection { get { return this.trackResurrection; } } public virtual T Target { get { object o = handle.Target; if ((o == null) || (!(o is T))) return default(T); else return (T)o; } set { handle = GCHandle.Alloc(value, this.trackResurrection ? GCHandleType.WeakTrackResurrection : GCHandleType.Weak); } } public override bool Equals(object obj) { var other = obj as WeakReference<T>; return other != null && Target.Equals(other.Target); } public override int GetHashCode() { return Target.GetHashCode(); } } It's functionality is trivial. I override operator + and - to get the += and -= syntactic sugar matching events. These create WeakReferences to the Action delegate. This allows the garbage collector to free the event target object (Bar in this example) when nobody else is holding on to it. In the Invoke() method, simply run through the weak references and call their Target Action. If any dead (i.e., garbage collected) references are found, remove them from the list. Of course, this only works with delegates of type Action. I tried making this generic, but ran into the missing where T : delegate in C#! As an alternative, simply modify class WeakReferenceEvent to be a WeakReferenceEvent, and replace the Action with Action. Fix the compiler errors and you have a class that can be used like so: class Foo { public WeakReferenceEvent<int> AnEvent = new WeakReferenceEvent<int>(); internal void DoEvent() { AnEvent.Invoke(5); } } Hopefully this will help someone else when they run into the mystery .NET event memory leak!

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Unable to connect to Samba printer

- by user127236

I have a headless Ubuntu 12.04 server for files and printers. It shares files via Samba just fine. However, the HP PSC-750xi connected to the server via USB is not accessible from my Ubuntu 12.04 laptop. I can browse for it in the Printing control panel, but any attempt to authenticate my ID to the printer with my user credentials results in the error "This print share is not accessible". I have included the Samba smb.conf file below. Any help appreciated. Thanks... JGB # # Sample configuration file for the Samba suite for Debian GNU/Linux. # # # This is the main Samba configuration file. You should read the # smb.conf(5) manual page in order to understand the options listed # here. Samba has a huge number of configurable options most of which # are not shown in this example # # Some options that are often worth tuning have been included as # commented-out examples in this file. # - When such options are commented with ";", the proposed setting # differs from the default Samba behaviour # - When commented with "#", the proposed setting is the default # behaviour of Samba but the option is considered important # enough to be mentioned here # # NOTE: Whenever you modify this file you should run the command # "testparm" to check that you have not made any basic syntactic # errors. # A well-established practice is to name the original file # "smb.conf.master" and create the "real" config file with # testparm -s smb.conf.master >smb.conf # This minimizes the size of the really used smb.conf file # which, according to the Samba Team, impacts performance # However, use this with caution if your smb.conf file contains nested # "include" statements. See Debian bug #483187 for a case # where using a master file is not a good idea. # #======================= Global Settings ======================= [global] log file = /var/log/samba/log.%m passwd chat = *Enter\snew\s*\spassword:* %n\n *Retype\snew\s*\spassword:* %n\n *password\supdated\ssuccessfully* . obey pam restrictions = yes map to guest = bad user encrypt passwords = true passwd program = /usr/bin/passwd %u passdb backend = tdbsam dns proxy = no writeable = yes server string = %h server (Samba, Ubuntu) unix password sync = yes workgroup = WORKGROUP syslog = 0 panic action = /usr/share/samba/panic-action %d usershare allow guests = yes max log size = 1000 pam password change = yes ## Browsing/Identification ### # Change this to the workgroup/NT-domain name your Samba server will part of # server string is the equivalent of the NT Description field # Windows Internet Name Serving Support Section: # WINS Support - Tells the NMBD component of Samba to enable its WINS Server # wins support = no # WINS Server - Tells the NMBD components of Samba to be a WINS Client # Note: Samba can be either a WINS Server, or a WINS Client, but NOT both ; wins server = w.x.y.z # This will prevent nmbd to search for NetBIOS names through DNS. # What naming service and in what order should we use to resolve host names # to IP addresses ; name resolve order = lmhosts host wins bcast #### Networking #### # The specific set of interfaces / networks to bind to # This can be either the interface name or an IP address/netmask; # interface names are normally preferred ; interfaces = 127.0.0.0/8 eth0 # Only bind to the named interfaces and/or networks; you must use the # 'interfaces' option above to use this. # It is recommended that you enable this feature if your Samba machine is # not protected by a firewall or is a firewall itself. However, this # option cannot handle dynamic or non-broadcast interfaces correctly. ; bind interfaces only = yes #### Debugging/Accounting #### # This tells Samba to use a separate log file for each machine # that connects # Cap the size of the individual log files (in KiB). # If you want Samba to only log through syslog then set the following # parameter to 'yes'. # syslog only = no # We want Samba to log a minimum amount of information to syslog. Everything # should go to /var/log/samba/log.{smbd,nmbd} instead. If you want to log # through syslog you should set the following parameter to something higher. # Do something sensible when Samba crashes: mail the admin a backtrace ####### Authentication ####### # "security = user" is always a good idea. This will require a Unix account # in this server for every user accessing the server. See # /usr/share/doc/samba-doc/htmldocs/Samba3-HOWTO/ServerType.html # in the samba-doc package for details. # security = user # You may wish to use password encryption. See the section on # 'encrypt passwords' in the smb.conf(5) manpage before enabling. # If you are using encrypted passwords, Samba will need to know what # password database type you are using. # This boolean parameter controls whether Samba attempts to sync the Unix # password with the SMB password when the encrypted SMB password in the # passdb is changed. # For Unix password sync to work on a Debian GNU/Linux system, the following # parameters must be set (thanks to Ian Kahan <<[email protected]> for # sending the correct chat script for the passwd program in Debian Sarge). # This boolean controls whether PAM will be used for password changes # when requested by an SMB client instead of the program listed in # 'passwd program'. The default is 'no'. # This option controls how unsuccessful authentication attempts are mapped # to anonymous connections ########## Domains ########### # Is this machine able to authenticate users. Both PDC and BDC # must have this setting enabled. If you are the BDC you must # change the 'domain master' setting to no # ; domain logons = yes # # The following setting only takes effect if 'domain logons' is set # It specifies the location of the user's profile directory # from the client point of view) # The following required a [profiles] share to be setup on the # samba server (see below) ; logon path = \\%N\profiles\%U # Another common choice is storing the profile in the user's home directory # (this is Samba's default) # logon path = \\%N\%U\profile # The following setting only takes effect if 'domain logons' is set # It specifies the location of a user's home directory (from the client # point of view) ; logon drive = H: # logon home = \\%N\%U # The following setting only takes effect if 'domain logons' is set # It specifies the script to run during logon. The script must be stored # in the [netlogon] share # NOTE: Must be store in 'DOS' file format convention ; logon script = logon.cmd # This allows Unix users to be created on the domain controller via the SAMR # RPC pipe. The example command creates a user account with a disabled Unix # password; please adapt to your needs ; add user script = /usr/sbin/adduser --quiet --disabled-password --gecos "" %u # This allows machine accounts to be created on the domain controller via the # SAMR RPC pipe. # The following assumes a "machines" group exists on the system ; add machine script = /usr/sbin/useradd -g machines -c "%u machine account" -d /var/lib/samba -s /bin/false %u # This allows Unix groups to be created on the domain controller via the SAMR # RPC pipe. ; add group script = /usr/sbin/addgroup --force-badname %g ########## Printing ########## # If you want to automatically load your printer list rather # than setting them up individually then you'll need this # load printers = yes # lpr(ng) printing. You may wish to override the location of the # printcap file ; printing = bsd ; printcap name = /etc/printcap # CUPS printing. See also the cupsaddsmb(8) manpage in the # cupsys-client package. ; printing = cups ; printcap name = cups ############ Misc ############ # Using the following line enables you to customise your configuration # on a per machine basis. The %m gets replaced with the netbios name # of the machine that is connecting ; include = /home/samba/etc/smb.conf.%m # Most people will find that this option gives better performance. # See smb.conf(5) and /usr/share/doc/samba-doc/htmldocs/Samba3-HOWTO/speed.html # for details # You may want to add the following on a Linux system: # SO_RCVBUF=8192 SO_SNDBUF=8192 # socket options = TCP_NODELAY # The following parameter is useful only if you have the linpopup package # installed. The samba maintainer and the linpopup maintainer are # working to ease installation and configuration of linpopup and samba. ; message command = /bin/sh -c '/usr/bin/linpopup "%f" "%m" %s; rm %s' & # Domain Master specifies Samba to be the Domain Master Browser. If this # machine will be configured as a BDC (a secondary logon server), you # must set this to 'no'; otherwise, the default behavior is recommended. # domain master = auto # Some defaults for winbind (make sure you're not using the ranges # for something else.) ; idmap uid = 10000-20000 ; idmap gid = 10000-20000 ; template shell = /bin/bash # The following was the default behaviour in sarge, # but samba upstream reverted the default because it might induce # performance issues in large organizations. # See Debian bug #368251 for some of the consequences of *not* # having this setting and smb.conf(5) for details. ; winbind enum groups = yes ; winbind enum users = yes # Setup usershare options to enable non-root users to share folders # with the net usershare command. # Maximum number of usershare. 0 (default) means that usershare is disabled. ; usershare max shares = 100 # Allow users who've been granted usershare privileges to create # public shares, not just authenticated ones #======================= Share Definitions ======================= # Un-comment the following (and tweak the other settings below to suit) # to enable the default home directory shares. This will share each # user's home director as \\server\username ;[homes] ; comment = Home Directories ; browseable = no # By default, the home directories are exported read-only. Change the # next parameter to 'no' if you want to be able to write to them. ; read only = yes # File creation mask is set to 0700 for security reasons. If you want to # create files with group=rw permissions, set next parameter to 0775. ; create mask = 0700 # Directory creation mask is set to 0700 for security reasons. If you want to # create dirs. with group=rw permissions, set next parameter to 0775. ; directory mask = 0700 # By default, \\server\username shares can be connected to by anyone # with access to the samba server. Un-comment the following parameter # to make sure that only "username" can connect to \\server\username # The following parameter makes sure that only "username" can connect # # This might need tweaking when using external authentication schemes ; valid users = %S # Un-comment the following and create the netlogon directory for Domain Logons # (you need to configure Samba to act as a domain controller too.) ;[netlogon] ; comment = Network Logon Service ; path = /home/samba/netlogon ; guest ok = yes ; read only = yes # Un-comment the following and create the profiles directory to store # users profiles (see the "logon path" option above) # (you need to configure Samba to act as a domain controller too.) # The path below should be writable by all users so that their # profile directory may be created the first time they log on ;[profiles] ; comment = Users profiles ; path = /home/samba/profiles ; guest ok = no ; browseable = no ; create mask = 0600 ; directory mask = 0700 [printers] comment = All Printers browseable = no path = /var/spool/samba printable = yes guest ok = no read only = yes create mask = 0700 # Windows clients look for this share name as a source of downloadable # printer drivers [print$] comment = Printer Drivers browseable = yes writeable = no path = /var/lib/samba/printers # Uncomment to allow remote administration of Windows print drivers. # You may need to replace 'lpadmin' with the name of the group your # admin users are members of. # Please note that you also need to set appropriate Unix permissions # to the drivers directory for these users to have write rights in it ; write list = root, @lpadmin # A sample share for sharing your CD-ROM with others. ;[cdrom] ; comment = Samba server's CD-ROM ; read only = yes ; locking = no ; path = /cdrom ; guest ok = yes # The next two parameters show how to auto-mount a CD-ROM when the # cdrom share is accesed. For this to work /etc/fstab must contain # an entry like this: # # /dev/scd0 /cdrom iso9660 defaults,noauto,ro,user 0 0 # # The CD-ROM gets unmounted automatically after the connection to the # # If you don't want to use auto-mounting/unmounting make sure the CD # is mounted on /cdrom # ; preexec = /bin/mount /cdrom ; postexec = /bin/umount /cdrom [mediafiles] path = /media/multimedia/

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Converting "A* Search" code from C++ to Java [on hold]

- by mr5

Updated! I get this code from this site It's A* Search Algorithm(finding shortest path with heuristics) I modify most of variable names and some if conditions from the original version to satisfy my syntactic taste. It works in C++ (as I can't see any trouble with it) but fails in Java version. Java Code: String findPath(int startX, int startY, int finishX, int finishY) { @SuppressWarnings("unchecked") LinkedList<Node>[] nodeList = (LinkedList<Node>[]) new LinkedList<?>[2]; nodeList[0] = new LinkedList<Node>(); nodeList[1] = new LinkedList<Node>(); Node n0; Node m0; int nlIndex = 0; // queueList index // reset the node maps for(int y = 0;y < ROW_COUNT; ++y) { for(int x = 0;x < COL_COUNT; ++x) { close_nodes_map[y][x] = 0; open_nodes_map[y][x] = 0; } } // create the start node and push into list of open nodes n0 = new Node( startX, startY, 0, 0 ); n0.updatePriority( finishX, finishY ); nodeList[nlIndex].push( n0 ); open_nodes_map[startY][startX] = n0.getPriority(); // mark it on the open nodes map // A* search while( !nodeList[nlIndex].isEmpty() ) { LinkedList<Node> pq = nodeList[nlIndex]; // get the current node w/ the highest priority // from the list of open nodes n0 = new Node( pq.peek().getX(), pq.peek().getY(), pq.peek().getIterCount(), pq.peek().getPriority()); int x = n0.getX(); int y = n0.getY(); nodeList[nlIndex].pop(); // remove the node from the open list open_nodes_map[y][x] = 0; // mark it on the closed nodes map close_nodes_map[y][x] = 1; // quit searching when the goal state is reached //if((*n0).estimate(finishX, finishY) == 0) if( x == finishX && y == finishY ) { // generate the path from finish to start // by following the directions String path = ""; while( !( x == startX && y == startY) ) { int j = dir_map[y][x]; int c = '0' + ( j + Node.DIRECTION_COUNT / 2 ) % Node.DIRECTION_COUNT; path = (char)c + path; x += DIR_X[j]; y += DIR_Y[j]; } return path; } // generate moves (child nodes) in all possible directions for(int i = 0; i < Node.DIRECTION_COUNT; ++i) { int xdx = x + DIR_X[i]; int ydy = y + DIR_Y[i]; // boundary check if (!(xdx >= 0 && xdx < COL_COUNT && ydy >= 0 && ydy < ROW_COUNT)) continue; if ( ( gridMap.getData( ydy, xdx ) == GridMap.WALKABLE || gridMap.getData( ydy, xdx ) == GridMap.FINISH) && close_nodes_map[ydy][xdx] != 1 ) { // generate a child node m0 = new Node( xdx, ydy, n0.getIterCount(), n0.getPriority() ); m0.nextLevel( i ); m0.updatePriority( finishX, finishY ); // if it is not in the open list then add into that if( open_nodes_map[ydy][xdx] == 0 ) { open_nodes_map[ydy][xdx] = m0.getPriority(); nodeList[nlIndex].push( m0 ); // mark its parent node direction dir_map[ydy][xdx] = ( i + Node.DIRECTION_COUNT / 2 ) % Node.DIRECTION_COUNT; } else if( open_nodes_map[ydy][xdx] > m0.getPriority() ) { // update the priority info open_nodes_map[ydy][xdx] = m0.getPriority(); // update the parent direction info dir_map[ydy][xdx] = ( i + Node.DIRECTION_COUNT / 2 ) % Node.DIRECTION_COUNT; // replace the node // by emptying one queueList to the other one // except the node to be replaced will be ignored // and the new node will be pushed in instead while( !(nodeList[nlIndex].peek().getX() == xdx && nodeList[nlIndex].peek().getY() == ydy ) ) { nodeList[1 - nlIndex].push( nodeList[nlIndex].pop() ); } nodeList[nlIndex].pop(); // remove the wanted node // empty the larger size queueList to the smaller one if( nodeList[nlIndex].size() > nodeList[ 1 - nlIndex ].size() ) nlIndex = 1 - nlIndex; while( !nodeList[nlIndex].isEmpty() ) { nodeList[1 - nlIndex].push( nodeList[nlIndex].pop() ); } nlIndex = 1 - nlIndex; nodeList[nlIndex].push( m0 ); // add the better node instead } } } } return ""; // no route found } Output1: Legends . = PATH ? = START X = FINISH 3,2,1 = OBSTACLES (Misleading path) Output2: Changing these lines: n0 = new Node( a, b, c, d ); m0 = new Node( e, f, g, h ); to n0.set( a, b, c, d ); m0.set( e, f, g, h ); I get (I'm really confused) C++ Code: std::string A_Star::findPath(int startX, int startY, int finishX, int finishY) { typedef std::queue<Node> List_Container; List_Container nodeList[2]; // list of open (not-yet-tried) nodes Node n0; Node m0; int pqIndex = 0; // nodeList index // reset the node maps for(int y = 0;y < ROW_COUNT; ++y) { for(int x = 0;x < COL_COUNT; ++x) { close_nodes_map[y][x] = 0; open_nodes_map[y][x] = 0; } } // create the start node and push into list of open nodes n0 = Node( startX, startY, 0, 0 ); n0.updatePriority( finishX, finishY ); nodeList[pqIndex].push( n0 ); open_nodes_map[startY][startX] = n0.getPriority(); // mark it on the open nodes map // A* search while( !nodeList[pqIndex].empty() ) { List_Container &pq = nodeList[pqIndex]; // get the current node w/ the highest priority // from the list of open nodes n0 = Node( pq.front().getX(), pq.front().getY(), pq.front().getIterCount(), pq.front().getPriority()); int x = n0.getX(); int y = n0.getY(); nodeList[pqIndex].pop(); // remove the node from the open list open_nodes_map[y][x] = 0; // mark it on the closed nodes map close_nodes_map[y][x] = 1; // quit searching when the goal state is reached //if((*n0).estimate(finishX, finishY) == 0) if( x == finishX && y == finishY ) { // generate the path from finish to start // by following the directions std::string path = ""; while( !( x == startX && y == startY) ) { int j = dir_map[y][x]; char c = '0' + ( j + DIRECTION_COUNT / 2 ) % DIRECTION_COUNT; path = c + path; x += DIR_X[j]; y += DIR_Y[j]; } return path; } // generate moves (child nodes) in all possible directions for(int i = 0; i < DIRECTION_COUNT; ++i) { int xdx = x + DIR_X[i]; int ydy = y + DIR_Y[i]; // boundary check if (!( xdx >= 0 && xdx < COL_COUNT && ydy >= 0 && ydy < ROW_COUNT)) continue; if ( ( pGrid->getData(ydy,xdx) == WALKABLE || pGrid->getData(ydy, xdx) == FINISH) && close_nodes_map[ydy][xdx] != 1 ) { // generate a child node m0 = Node( xdx, ydy, n0.getIterCount(), n0.getPriority() ); m0.nextLevel( i ); m0.updatePriority( finishX, finishY ); // if it is not in the open list then add into that if( open_nodes_map[ydy][xdx] == 0 ) { open_nodes_map[ydy][xdx] = m0.getPriority(); nodeList[pqIndex].push( m0 ); // mark its parent node direction dir_map[ydy][xdx] = ( i + DIRECTION_COUNT / 2 ) % DIRECTION_COUNT; } else if( open_nodes_map[ydy][xdx] > m0.getPriority() ) { // update the priority info open_nodes_map[ydy][xdx] = m0.getPriority(); // update the parent direction info dir_map[ydy][xdx] = ( i + DIRECTION_COUNT / 2 ) % DIRECTION_COUNT; // replace the node // by emptying one nodeList to the other one // except the node to be replaced will be ignored // and the new node will be pushed in instead while ( !( nodeList[pqIndex].front().getX() == xdx && nodeList[pqIndex].front().getY() == ydy ) ) { nodeList[1 - pqIndex].push( nodeList[pqIndex].front() ); nodeList[pqIndex].pop(); } nodeList[pqIndex].pop(); // remove the wanted node // empty the larger size nodeList to the smaller one if( nodeList[pqIndex].size() > nodeList[ 1 - pqIndex ].size() ) pqIndex = 1 - pqIndex; while( !nodeList[pqIndex].empty() ) { nodeList[1-pqIndex].push(nodeList[pqIndex].front()); nodeList[pqIndex].pop(); } pqIndex = 1 - pqIndex; nodeList[pqIndex].push( m0 ); // add the better node instead } } } } return ""; // no route found } Output: Legends . = PATH ? = START X = FINISH 3,2,1 = OBSTACLES (Just right) From what I read about Java's documentation, I came up with the conclusion: C++'s std::queue<T>::front() == Java's LinkedList<T>.peek() Java's LinkedList<T>.pop() == C++'s std::queue<T>::front() + std::queue<T>::pop() What might I be missing in my Java version? In what way does it became different algorithmically from the C++ version?

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