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  • Programmatic binding of accelerators in wxPython

    - by Inductiveload
    I am trying to programmatically create and bind a table of accelerators in wxPython in a loop so that I don't need to worry about getting and assigning new IDs to each accelerators (and with a view to inhaling the handler list from some external resource, rather than hard-coding them). I also pass in some arguments to the handler via a lambda since a lot of my handlers will be the same but with different parameters (move, zoom, etc). The class is subclassed from wx.Frame and setup_accelerators() is called during initialisation. def setup_accelerators(self): bindings = [ (wx.ACCEL_CTRL, wx.WXK_UP, self.on_move, 'up'), (wx.ACCEL_CTRL, wx.WXK_DOWN, self.on_move, 'down'), (wx.ACCEL_CTRL, wx.WXK_LEFT, self.on_move, 'left'), (wx.ACCEL_CTRL, wx.WXK_RIGHT, self.on_move, 'right'), ] accelEntries = [] for binding in bindings: eventId = wx.NewId() accelEntries.append( (binding[0], binding[1], eventId) ) self.Bind(wx.EVT_MENU, lambda event: binding[2](event, binding[3]), id=eventId) accelTable = wx.AcceleratorTable(accelEntries) self.SetAcceleratorTable(accelTable) def on_move(self, e, direction): print direction However, this appears to bind all the accelerators to the last entry, so that Ctrl+Up prints "right", as do all the other three. How to correctly bind multiple handlers in this way?

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  • Returning a href within a string

    - by user701254
    How can I return a href within a string, I can access the start position but not sure how to get last position : Here is what I have so far : String str = "sadf ad fas dfa http:\\www.google.com sdfa sadf as dfas"; int index = str.indexOf("http"); String href = str.substring(index , ???); What should the end index be ? Note, this is targeted at j2me & I need to minimise download footprint so I cannot use regular expressions or third party regular expressions libraries.

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  • How do I do this in Python (File Manipulation)?

    - by ThinkCode
    I have a bunch of HTML files in HTML folder. Those HTML files have unicode characters which I solved by using filter(lambda x: x in string.printable, line). Now how do I write the changes back to the original file? What is the best way of doing it? Each HTML file is of 30 kb in size. 1 import os, string 2 3 for file in os.listdir("HTML/"): 4 print file 5 myfile = open('HTML/' + file) 6 fileList = myfile.readlines() 9 for line in fileList: 10 #print line 11 line = filter(lambda x: x in string.printable, line) 12 myfile.close()

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  • Fixing Robocopy for SQL Server Jobs

    - by Most Valuable Yak (Rob Volk)
    Robocopy is one of, if not the, best life-saving/greatest-thing-since-sliced-bread command line utilities ever to come from Microsoft.  If you're not using it already, what are you waiting for? Of course, being a Microsoft product, it's not exactly perfect. ;)  Specifically, it sets the ERRORLEVEL to a non-zero value even if the copy is successful.  This causes a problem in SQL Server job steps, since non-zero ERRORLEVELs report as failed. You can work around this by having your SQL job go to the next step on failure, but then you can't determine if there was a genuine error.  Plus you still see annoying red X's in your job history.  One way I've found to avoid this is to use a batch file that runs Robocopy, and I add some commands after it (in red): robocopy d:\backups \\BackupServer\BackupFolder *.bak rem suppress successful robocopy exit statuses, only report genuine errors (bitmask 16 and 8 settings)set/A errlev="%ERRORLEVEL% & 24" rem exit batch file with errorlevel so SQL job can succeed or fail appropriatelyexit/B %errlev% (The REM statements are simply comments and don't need to be included in the batch file) The SET command lets you use expressions when you use the /A switch.  So I set an environment variable "errlev" to a bitwise AND with the ERRORLEVEL value. Robocopy's exit codes use a bitmap/bitmask to specify its exit status.  The bits for 1, 2, and 4 do not indicate any kind of failure, but 8 and 16 do.  So by adding 16 + 8 to get 24, and doing a bitwise AND, I suppress any of the other bits that might be set, and allow either or both of the error bits to pass. The next step is to use the EXIT command with the /B switch to set a new ERRORLEVEL value, using the "errlev" variable.  This will now return zero (unless Robocopy had real errors) and allow your SQL job step to report success. This technique should also work for other command-line utilities.  The only issues I've found is that it requires the commands to be part of a batch file, so if you use Robocopy directly in your SQL job step you'd need to place it in a batch.  If you also have multiple Robocopy calls, you'll need to place the SET/A command ONLY after the last one.  You'd therefore lose any errors from previous calls, unless you use multiple "errlev" variables and AND them together. (I'll leave this as an exercise for the reader) The SET/A syntax also permits other kinds of expressions to be calculated.  You can get a full list by running "SET /?" on a command prompt.

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  • Parsing SQLIO Output to Excel Charts using Regex in PowerShell

    - by Jonathan Kehayias
    Today Joe Webb ( Blog | Twitter ) blogged about The Power of Regex in Powershell, and in his post he shows how to parse the SQL Server Error Log for events of interest.  At the end of his blog post Joe asked about other places where Regular Expressions have been useful in PowerShell so I thought I’d blog my script for parsing SQLIO output using Regex in PowerShell, to populate an Excel worksheet and build charts based on the results automatically. If you’ve never used SQLIO, Brent Ozar ( Blog...(read more)

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  • Parsing SQLIO Output to Excel Charts using Regex in PowerShell

    - by Jonathan Kehayias
    Today Joe Webb ( Blog | Twitter ) blogged about The Power of Regex in Powershell, and in his post he shows how to parse the SQL Server Error Log for events of interest. At the end of his blog post Joe asked about other places where Regular Expressions have been useful in PowerShell so I thought I’d blog my script for parsing SQLIO output using Regex in PowerShell, to populate an Excel worksheet and build charts based on the results automatically. If you’ve never used SQLIO, Brent Ozar ( Blog | Twitter...(read more)

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  • C# Java Objective-C need expert advices

    - by Kevino
    Which platform as the edge today in 2012 with the rise of cloud computing, mobile development and the revolution of HTML5/Javascript between J2EE, .Net framework and IOS Objective-C ??? I want to start learning 1 language between Java, C# and Objective-C and get back into programming after 14 years and I don't know which to choose I need expert advices... I already know a little C++ and I remember my concepts in example pointers arithmetic, class etc so I tend to prefer learning C# and Objective-C but I've been told by some experienced programmers that Windows 8 could flop and .Net could be going away slowly since C++ and Html5/Javascript could be king in mobile is that true ? and that C# is more advanced compared to Java with Linq/Lambda... but not truly as portable if we consider android, etc but Java as a lot going for him too Scala, Clojure, Groovy, JRuby, JPython etc etc so I am lost Please help me, and don't close this right away I really need help and expert advices thanks you very much ANSWER : ElYusubov : thanks for everything please continue with the answers/explanations I just did some native C++ in dos mode in 1998 before Cli and .Net I don't know the STL,Templates, Win32 or COM but I remember a little the concept of memory management and oop etc I already played around a little with C# 1.0 in 2002 but things changed a lot with linq and lambda... I am here because I talked with some experienced programmers and authors of some the best selling programming books like apress wrox and deitel and they told me a few things are likely to happen like .Net could be on his way out because of Html5/Javascript combo could kill xaml and C++ native apps on mobile dev will outperform them by a lot... Secondly ios and android are getting so popular that mobile dev is the future so Objective-C is very hard to ignore so why get tied down in Windows long term (.Net) compared to Java (android)... but again android is very fragmented, they also said Windows 8 RT will give you access to only a small part of the .Net framework... so that's what they think so I don't know which direction to choose I wanted to learn C# & .Net but what if it die off or Windows 8 flop Windows Phone marketshare really can't compare to ios... so I'll be stuck that's why I worry is Java safer long term or more versatile if you want 'cause of the support for android ??

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  • Dicas do C# 4 consumindo uma DLL da Daruma com o mestre Claudenir

    - by renatohaddad
    Olá pessoal, recentemente tive o prazer de compartilhar o conhecimento com o time de desenvolvedores da Daruma e o Claudenir me convidou para gravar este vídeo mostrando como usar alguns recursos de parâmetros opcionais e expressões Lammmmmmbda no C# 4.O código contou com a presença do Felipe, da equipe da Daruma, o qual me mostrou quais métodos poderiamos consumir. Como não conheço nada da DLLs deles, o Felipe indicou quais poderíamos consumir retornando dados, então montamos uma coleção com Genérics e aplicamos lambda para extrair infos.Confira o vídeo em http://www.youtube.com/darumadeveloper#p/u/0/Ps2ddDYhkPUAbração.

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  • Autofac

    - by csharp-source.net
    A .NET IoC container written in C#. Focus on programmatic configuration with builder syntax. Zero intrusion into existing code. Create components using reflection or with lambda expressions for unlimited flexibility. Managed disposal of any IDisposable components created by the container within a defined scope.

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  • Of C# Iterators and Performance

    - by James Michael Hare
    Some of you reading this will be wondering, "what is an iterator" and think I'm locked in the world of C++.  Nope, I'm talking C# iterators.  No, not enumerators, iterators.   So, for those of you who do not know what iterators are in C#, I will explain it in summary, and for those of you who know what iterators are but are curious of the performance impacts, I will explore that as well.   Iterators have been around for a bit now, and there are still a bunch of people who don't know what they are or what they do.  I don't know how many times at work I've had a code review on my code and have someone ask me, "what's that yield word do?"   Basically, this post came to me as I was writing some extension methods to extend IEnumerable<T> -- I'll post some of the fun ones in a later post.  Since I was filtering the resulting list down, I was using the standard C# iterator concept; but that got me wondering: what are the performance implications of using an iterator versus returning a new enumeration?   So, to begin, let's look at a couple of methods.  This is a new (albeit contrived) method called Every(...).  The goal of this method is to access and enumeration and return every nth item in the enumeration (including the first).  So Every(2) would return items 0, 2, 4, 6, etc.   Now, if you wanted to write this in the traditional way, you may come up with something like this:       public static IEnumerable<T> Every<T>(this IEnumerable<T> list, int interval)     {         List<T> newList = new List<T>();         int count = 0;           foreach (var i in list)         {             if ((count++ % interval) == 0)             {                 newList.Add(i);             }         }           return newList;     }     So basically this method takes any IEnumerable<T> and returns a new IEnumerable<T> that contains every nth item.  Pretty straight forward.   The problem?  Well, Every<T>(...) will construct a list containing every nth item whether or not you care.  What happens if you were searching this result for a certain item and find that item after five tries?  You would have generated the rest of the list for nothing.   Enter iterators.  This C# construct uses the yield keyword to effectively defer evaluation of the next item until it is asked for.  This can be very handy if the evaluation itself is expensive or if there's a fair chance you'll never want to fully evaluate a list.   We see this all the time in Linq, where many expressions are chained together to do complex processing on a list.  This would be very expensive if each of these expressions evaluated their entire possible result set on call.    Let's look at the same example function, this time using an iterator:       public static IEnumerable<T> Every<T>(this IEnumerable<T> list, int interval)     {         int count = 0;         foreach (var i in list)         {             if ((count++ % interval) == 0)             {                 yield return i;             }         }     }   Notice it does not create a new return value explicitly, the only evidence of a return is the "yield return" statement.  What this means is that when an item is requested from the enumeration, it will enter this method and evaluate until it either hits a yield return (in which case that item is returned) or until it exits the method or hits a yield break (in which case the iteration ends.   Behind the scenes, this is all done with a class that the CLR creates behind the scenes that keeps track of the state of the iteration, so that every time the next item is asked for, it finds that item and then updates the current position so it knows where to start at next time.   It doesn't seem like a big deal, does it?  But keep in mind the key point here: it only returns items as they are requested. Thus if there's a good chance you will only process a portion of the return list and/or if the evaluation of each item is expensive, an iterator may be of benefit.   This is especially true if you intend your methods to be chainable similar to the way Linq methods can be chained.    For example, perhaps you have a List<int> and you want to take every tenth one until you find one greater than 10.  We could write that as:       List<int> someList = new List<int>();         // fill list here         someList.Every(10).TakeWhile(i => i <= 10);     Now is the difference more apparent?  If we use the first form of Every that makes a copy of the list.  It's going to copy the entire list whether we will need those items or not, that can be costly!    With the iterator version, however, it will only take items from the list until it finds one that is > 10, at which point no further items in the list are evaluated.   So, sounds neat eh?  But what's the cost is what you're probably wondering.  So I ran some tests using the two forms of Every above on lists varying from 5 to 500,000 integers and tried various things.    Now, iteration isn't free.  If you are more likely than not to iterate the entire collection every time, iterator has some very slight overhead:   Copy vs Iterator on 100% of Collection (10,000 iterations) Collection Size Num Iterated Type Total ms 5 5 Copy 5 5 5 Iterator 5 50 50 Copy 28 50 50 Iterator 27 500 500 Copy 227 500 500 Iterator 247 5000 5000 Copy 2266 5000 5000 Iterator 2444 50,000 50,000 Copy 24,443 50,000 50,000 Iterator 24,719 500,000 500,000 Copy 250,024 500,000 500,000 Iterator 251,521   Notice that when iterating over the entire produced list, the times for the iterator are a little better for smaller lists, then getting just a slight bit worse for larger lists.  In reality, given the number of items and iterations, the result is near negligible, but just to show that iterators come at a price.  However, it should also be noted that the form of Every that returns a copy will have a left-over collection to garbage collect.   However, if we only partially evaluate less and less through the list, the savings start to show and make it well worth the overhead.  Let's look at what happens if you stop looking after 80% of the list:   Copy vs Iterator on 80% of Collection (10,000 iterations) Collection Size Num Iterated Type Total ms 5 4 Copy 5 5 4 Iterator 5 50 40 Copy 27 50 40 Iterator 23 500 400 Copy 215 500 400 Iterator 200 5000 4000 Copy 2099 5000 4000 Iterator 1962 50,000 40,000 Copy 22,385 50,000 40,000 Iterator 19,599 500,000 400,000 Copy 236,427 500,000 400,000 Iterator 196,010       Notice that the iterator form is now operating quite a bit faster.  But the savings really add up if you stop on average at 50% (which most searches would typically do):     Copy vs Iterator on 50% of Collection (10,000 iterations) Collection Size Num Iterated Type Total ms 5 2 Copy 5 5 2 Iterator 4 50 25 Copy 25 50 25 Iterator 16 500 250 Copy 188 500 250 Iterator 126 5000 2500 Copy 1854 5000 2500 Iterator 1226 50,000 25,000 Copy 19,839 50,000 25,000 Iterator 12,233 500,000 250,000 Copy 208,667 500,000 250,000 Iterator 122,336   Now we see that if we only expect to go on average 50% into the results, we tend to shave off around 40% of the time.  And this is only for one level deep.  If we are using this in a chain of query expressions it only adds to the savings.   So my recommendation?  If you have a resonable expectation that someone may only want to partially consume your enumerable result, I would always tend to favor an iterator.  The cost if they iterate the whole thing does not add much at all -- and if they consume only partially, you reap some really good performance gains.   Next time I'll discuss some of my favorite extensions I've created to make development life a little easier and maintainability a little better.

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  • Google Python Class Day 2 Part 1

    Google Python Class Day 2 Part 1 Google Python Class Day 2 Part 1: Regular Expressions. By Nick Parlante. Support materials and exercises: code.google.com From: GoogleDevelopers Views: 18 0 ratings Time: 42:00 More in Science & Technology

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  • tile_static, tile_barrier, and tiled matrix multiplication with C++ AMP

    - by Daniel Moth
    We ended the previous post with a mechanical transformation of the C++ AMP matrix multiplication example to the tiled model and in the process introduced tiled_index and tiled_grid. This is part 2. tile_static memory You all know that in regular CPU code, static variables have the same value regardless of which thread accesses the static variable. This is in contrast with non-static local variables, where each thread has its own copy. Back to C++ AMP, the same rules apply and each thread has its own value for local variables in your lambda, whereas all threads see the same global memory, which is the data they have access to via the array and array_view. In addition, on an accelerator like the GPU, there is a programmable cache, a third kind of memory type if you'd like to think of it that way (some call it shared memory, others call it scratchpad memory). Variables stored in that memory share the same value for every thread in the same tile. So, when you use the tiled model, you can have variables where each thread in the same tile sees the same value for that variable, that threads from other tiles do not. The new storage class for local variables introduced for this purpose is called tile_static. You can only use tile_static in restrict(direct3d) functions, and only when explicitly using the tiled model. What this looks like in code should be no surprise, but here is a snippet to confirm your mental image, using a good old regular C array // each tile of threads has its own copy of locA, // shared among the threads of the tile tile_static float locA[16][16]; Note that tile_static variables are scoped and have the lifetime of the tile, and they cannot have constructors or destructors. tile_barrier In amp.h one of the types introduced is tile_barrier. You cannot construct this object yourself (although if you had one, you could use a copy constructor to create another one). So how do you get one of these? You get it, from a tiled_index object. Beyond the 4 properties returning index objects, tiled_index has another property, barrier, that returns a tile_barrier object. The tile_barrier class exposes a single member, the method wait. 15: // Given a tiled_index object named t_idx 16: t_idx.barrier.wait(); 17: // more code …in the code above, all threads in the tile will reach line 16 before a single one progresses to line 17. Note that all threads must be able to reach the barrier, i.e. if you had branchy code in such a way which meant that there is a chance that not all threads could reach line 16, then the code above would be illegal. Tiled Matrix Multiplication Example – part 2 So now that we added to our understanding the concepts of tile_static and tile_barrier, let me obfuscate rewrite the matrix multiplication code so that it takes advantage of tiling. Before you start reading this, I suggest you get a cup of your favorite non-alcoholic beverage to enjoy while you try to fully understand the code. 01: void MatrixMultiplyTiled(vector<float>& vC, const vector<float>& vA, const vector<float>& vB, int M, int N, int W) 02: { 03: static const int TS = 16; 04: array_view<const float,2> a(M, W, vA); 05: array_view<const float,2> b(W, N, vB); 06: array_view<writeonly<float>,2> c(M,N,vC); 07: parallel_for_each(c.grid.tile< TS, TS >(), 08: [=] (tiled_index< TS, TS> t_idx) restrict(direct3d) 09: { 10: int row = t_idx.local[0]; int col = t_idx.local[1]; 11: float sum = 0.0f; 12: for (int i = 0; i < W; i += TS) { 13: tile_static float locA[TS][TS], locB[TS][TS]; 14: locA[row][col] = a(t_idx.global[0], col + i); 15: locB[row][col] = b(row + i, t_idx.global[1]); 16: t_idx.barrier.wait(); 17: for (int k = 0; k < TS; k++) 18: sum += locA[row][k] * locB[k][col]; 19: t_idx.barrier.wait(); 20: } 21: c[t_idx.global] = sum; 22: }); 23: } Notice that all the code up to line 9 is the same as per the changes we made in part 1 of tiling introduction. If you squint, the body of the lambda itself preserves the original algorithm on lines 10, 11, and 17, 18, and 21. The difference being that those lines use new indexing and the tile_static arrays; the tile_static arrays are declared and initialized on the brand new lines 13-15. On those lines we copy from the global memory represented by the array_view objects (a and b), to the tile_static vanilla arrays (locA and locB) – we are copying enough to fit a tile. Because in the code that follows on line 18 we expect the data for this tile to be in the tile_static storage, we need to synchronize the threads within each tile with a barrier, which we do on line 16 (to avoid accessing uninitialized memory on line 18). We also need to synchronize the threads within a tile on line 19, again to avoid the race between lines 14, 15 (retrieving the next set of data for each tile and overwriting the previous set) and line 18 (not being done processing the previous set of data). Luckily, as part of the awesome C++ AMP debugger in Visual Studio there is an option that helps you find such races, but that is a story for another blog post another time. May I suggest reading the next section, and then coming back to re-read and walk through this code with pen and paper to really grok what is going on, if you haven't already? Cool. Why would I introduce this tiling complexity into my code? Funny you should ask that, I was just about to tell you. There is only one reason we tiled our extent, had to deal with finding a good tile size, ensure the number of threads we schedule are correctly divisible with the tile size, had to use a tiled_index instead of a normal index, and had to understand tile_barrier and to figure out where we need to use it, and double the size of our lambda in terms of lines of code: the reason is to be able to use tile_static memory. Why do we want to use tile_static memory? Because accessing tile_static memory is around 10 times faster than accessing the global memory on an accelerator like the GPU, e.g. in the code above, if you can get 150GB/second accessing data from the array_view a, you can get 1500GB/second accessing the tile_static array locA. And since by definition you are dealing with really large data sets, the savings really pay off. We have seen tiled implementations being twice as fast as their non-tiled counterparts. Now, some algorithms will not have performance benefits from tiling (and in fact may deteriorate), e.g. algorithms that require you to go only once to global memory will not benefit from tiling, since with tiling you already have to fetch the data once from global memory! Other algorithms may benefit, but you may decide that you are happy with your code being 150 times faster than the serial-version you had, and you do not need to invest to make it 250 times faster. Also algorithms with more than 3 dimensions, which C++ AMP supports in the non-tiled model, cannot be tiled. Also note that in future releases, we may invest in making the non-tiled model, which already uses tiling under the covers, go the extra step and use tile_static memory on your behalf, but it is obviously way to early to commit to anything like that, and we certainly don't do any of that today. Comments about this post by Daniel Moth welcome at the original blog.

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  • Visual Basic Book Excerpt: Useful Namespaces

    This chapter provides an overview of some of the most important system namespaces and gives more detailed examples that demonstrate regular expressions, XML, cryptography, reflection, threading, parallel programming, and Direct3D....Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • Stairway to XML: Level 7 - Updating Data in an XML Instance

    You need to provide the necessary keywords and define the XQuery and value expressions in your XML DML expression in order to use the modify() method to update element and attribute values in either typed or untyped XML instances in an XML column. Robert Sheldon explains how. "It really helped us isolate where we were experiencing a bottleneck"- John Q Martin, SQL Server DBA. Get started with SQL Monitor today to solve tricky performance problems - download a free trial

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  • How would you rank these programming skills in order of learning them? [closed]

    - by mumtaz
    As a general purpose programmer, what should you learn first and what should you learn later on? Here are some skills I wonder about... SQL Regular Expressions Multi-threading / Concurrency Functional Programming Graphics The mastery of your mother programming language's syntax/semantics/featureset The mastery of your base class framework libraries Version Control System Unit Testing XML Do you know other important ones? Please specify them... On which skills should I focus first?

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  • Prevent hotlinking of attachments

    - by reggie
    People are able to embed my forum's attachments (vbulletin). I tried to create an htaccess rule for the hotlinking, but it did not work. RewriteCond %{HTTP_REFERER} !^$ RewriteCond %{HTTP_REFERER} !^http://(www\.)?mydomain\.com.*$ [NC] RewriteRule attachmentid=\d+(\&d=\d*)?|\.([Gg][Ii][Ff]|[Jj][Pp][Gg])$ http://mydomain.com/antihotlink.jpeg [R] Is it not possible to check for numbers in regular expressions in htaccess files?

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  • What is a good replacement for MS Frontpage?

    - by Clay Nichols
    I've been using MS Frontpage 2003 to maintain our company website for years. Looking for a replacement that can: Import/convert a MS FrontPage website and "modernize it" (clean up the HTML to make it standards compliant, etc.) Supports (or converts) the substitutions (Include Page and Text substitutions that are done when the page is published (so they become static HTML). Leverages my knowledge of FrontPage Looks like the likely contender is Web Expressions but I'm open to objective suggestions.

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  • Can't understand example using continuations

    - by Matt Fenwick
    I'm reading the r6rs Scheme report and am confused by the explanation of continuations (I find it to be too dense and lacking of examples for a beginner). What is this code doing and how does it evaluate to 4? Why does call/cc want an argument that's a function of one argument? How is call/cc's argument used? (+ 1 (call-with-current-continuation (lambda (escape) (+ 2 (escape 3))))) =? 4 This example is from section 1.11 - Continuations.

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