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  • Formalizing a requirements spec written in narrative English

    - by ProfK
    I have a fairly technical functionality requirements spec, expressed in English prose, produced by my project manager. It is structured as a collection of UI tabs, where the requirements for each tab are expressed as a lit of UI fields and a list of business rules for the tab. Most business rules are for UI fields on a tab, e.g: a) Must be alphanumeric, max length 20. b) Must be a dropdown, with values from table x. c) Is mandatory. d) Is mandatory under certain conditions, e.g. another field is just populated, or has a specific value. Then other business rules get a little more complex. The spec is for a job application, so the central business object (table) is the Applicant, and we have several other tables with one-to-many relationships with applicant, such as Degree, HighSchool, PreviousEmployer, Diploma, etc. e) One such complex rule says a status field can only be assigned a certain value if a many-side record exists in at least one of the many-side tables. E.g. the Applicant has at least one HighSchool or at least one Diploma record. I am looking for advice on how to codify these requirements into a more structured specification defined in terms of tables, fields, and relationships, especially for the conditional rules for fields and for the presence of related records. Any suggestions and advice will be most welcome, but I would be overjoyed if i could find an already defined system or structure for expressing things like this.

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  • Correct For Loop Design

    - by Yttrill
    What is the correct design for a for loop? Felix currently uses if len a > 0 do for var i in 0 upto len a - 1 do println a.[i]; done done which is inclusive of the upper bound. This is necessary to support the full range of values of a typical integer type. However the for loop shown does not support zero length arrays, hence the special test, nor will the subtraction of 1 work convincingly if the length of the array is equal to the number of integers. (I say convincingly because it may be that 0 - 1 = maxval: this is true in C for unsigned int, but are you sure it is true for unsigned char without thinking carefully about integral promotions?) The actual implementation of the for loop by my compiler does correctly handle 0 but this requires two tests to implement the loop: continue: if not (i <= bound) goto break body if i == bound goto break ++i goto continue break: Throw in the hand coded zero check in the array example and three tests are needed. If the loop were exclusive it would handle zero properly, avoiding the special test, but there'd be no way to express the upper bound of an array with maximum size. Note the C way of doing this: for(i=0; predicate(i); increment(i)) has the same problem. The predicate is tested after the increment, but the terminating increment is not universally valid! There is a general argument that a simple exclusive loop is enough: promote the index to a large type to prevent overflow, and assume no one will ever loop to the maximum value of this type.. but I'm not entirely convinced: if you promoted to C's size_t and looped from the second largest value to the largest you'd get an infinite loop!

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  • How should I start with Lisp?

    - by Gary Rowe
    I've been programming for years now, working my way through various iterations of Blub (BASIC, Assembler, C, C++, Visual Basic, Java, Ruby in no particular order of "Blub-ness") and I'd like to learn Lisp. However, I have a lot of intertia what with limited time (family, full time job etc) and a comfortable happiness with my current Blub (Java). So my question is this, given that I'm someone who would really like to learn Lisp, what would be the initial steps to get a good result that demonstrates the superiority of Lisp in web development? Maybe I'm missing the point, but that's how I would initially see the application of my Lisp knowledge. I'm thinking "use dialect A, use IDE B, follow instructions on page C, question your sanity after monads using counsellor D". I'd just like to know what people here consider to be an optimal set of values for A, B, C and perhaps D. Also some discussion on the relative merit of learning such a powerful language as opposed to, say, becoming a Rails expert. Just to add some more detail, I'll be developing on MacOS (or a Linux VM) - no Windows based approaches will be necessary, thanks. Notes for those just browsing by I'm going to keep this question open for a while so that I can offer feedback on the suggestions after I've been able to explore them. If you happen to be browsing by and feel you have something to add, please do. I would really welcome your feedback. Interesting links Assuming you're coming at Lisp from a Java background, this set of links will get you started quickly. Using Intellij's La Clojure plugin to integrate Lisp (videocast) Lisp for the Web Online version of Practical Common Lisp (c/o Frank Shearar) Land of Lisp a (+ (+ very quirky) game based) way in but makes it all so straightforward

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  • Need help with Microsoft Access 07 & Reports

    - by Moe
    I'm finding it difficult to get MS reporting working to what I'd like to show. What I'm trying to do is: a) In my database store a URL file (HTTP external file), that is a .jpeg. I'd like to use that URL to call the image on the report sheet. I have tried to use 'Control source' on the data panel, but with no success. Any way I can get Dynamic Images to show up on each database. Also, I have a couple of Relational Databases. One Defines Values: For Example: DefinePets('petID','Name of Pet') The other one links the Main DB with the 'DefinePets' database. Eg: connect('petID','mainID','extraFeild') I'd like my report to Go into the "connect" Table, where the the currently viewed Record Value = mainID, then find petID and return Name of Pet. There is a many to many link between definePets and the main Table. (Therefore connect is joining them up) Or is that too much to ask from a simple package like Access?

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  • SQL SERVER – Select Columns from Stored Procedure Resultset

    - by Pinal Dave
    It is fun to go back to basics often. Here is the one classic question: “How to select columns from Stored Procedure Resultset?” Though Stored Procedure has been introduced many years ago, the question about retrieving columns from Stored Procedure is still very popular with beginners. Let us see the solution in quick steps. First we will create a sample stored procedure. CREATE PROCEDURE SampleSP AS SELECT 1 AS Col1, 2 AS Col2 UNION SELECT 11, 22 GO Now we will create a table where we will temporarily store the result set of stored procedures. We will be using INSERT INTO and EXEC command to retrieve the values and insert into temporary table. CREATE TABLE #TempTable (Col1 INT, Col2 INT) GO INSERT INTO #TempTable EXEC SampleSP GO Next we will retrieve our data from stored procedure. SELECT * FROM #TempTable GO Finally we will clean up all the objects which we have created. DROP TABLE #TempTable DROP PROCEDURE SampleSP GO Let me know if you want me to share such back to basic tips. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Stored Procedure, SQL Tips and Tricks, T SQL

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  • ADF EMG Task Flow Tester Now Available!

    - by Steven Davelaar
    Testing ADF applications has become much easier as of today. At the ADF EMG day at Oracle Open World a new tool was announced, the ADF EMG Task Flow Tester.  The ADF EMG Task Flow Tester is a web-based testing tool for ADF bounded task flows. It supports testing of task flows that use pages as well as task flows using page fragments. A sophisticated mechanism to specify task flow input parameters is provided. A set of task flow input parameters and run options can be saved as a task flow testcase. Task flows and their testcases can be exported to XML and imported from XML.      This ADF EMG task Flow Tester can help you in a number of ways: It allows you to unit test your task flows in complete isolation, ruling out dependencies with other task flows when finding and investigating issues. It allows you to quickly test various combinations of task flow input parameter without redeploying the application It keeps your application cleaner (and saves time) as you no longer need to create separate test pages for each and every bounded task flow with page fragments that you used to create before. You can use the tester to simulate a call to your task flow so you can easily test task flow return values and the return navigation outcome. The tool is easy to install as a JDeveloper extension, and easy to use. Check out the Getting Started section in the User Guide and you will be up and running in 5 minutes! Your feedback is most welcome, if you run into issues or have enhancement requests, then check out this page.

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  • Why is my firewall preventing me from accessing some websites

    - by nosx
    I have an old Belkin router and when I enable the firewall I cannot access certain websites. For example: http://www.avisynth.org With Firewall Enabled: Main page loads and begins to do a meta refresh which never finishes. With Firewall Disabled: Main page loads and the meta refresh completes as normal and I am taken to the wiki page. I have not setup any rules in my firewall that would prevent this site from loading, yet it refuses to load unless I have the firewall disabled completely. My router has a hidden page with advanced settings on it for the firewall which I was able to acccess and take a screenshot of, but I did not want to mess with these values unless I absolutely have to do so: What might be causing this problem and how would I go about fixing it?

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  • Bash completion doesn't work, or is ignoring what I've typed; but works for commands

    - by Neil Traft
    Bash completion seems to be ignoring what I've typed (it tries to complete, but acts as if there's nothing under the cursor). I know I saw it work on this machine earlier today, but I'm not sure what has changed. Some examples: cd shows all directories under my current folder: $ cd co<tab><tab> cmake/ config/ doc/ examples/ include/ programs/ sandbox/ src/ .svn/ tests/ Commands like ls and less show all files and directories under my current folder: $ ls co<tab><tab> cmake/ config/ .cproject Doxyfile.in include/ programs/ README.txt src/ tests/ CMakeLists.txt COPYING.txt doc/ examples/ mainpage.dox .project sandbox/ .svn/ Even when I try to complete things from a different folder, it gives me only the results for my current folder (telling me that it is completely ignoring what I've typed): $ cd ~/D<tab><tab> cmake/ config/ doc/ examples/ include/ programs/ sandbox/ src/ .svn/ tests/ But it seems to be working fine for commands and variables: $ if<tab><tab> if ifconfig ifdown ifnames ifquery ifup $ echo $P<tab><tab> $PATH $PIPESTATUS $PPID $PS1 $PS2 $PS4 $PWD $PYTHONPATH I do have this bit in my .bashrc, and I have confirmed that my .bashrc is indeed getting sourced: if [ -f /etc/bash_completion ] && ! shopt -oq posix; then . /etc/bash_completion fi I've even tried manually executing that file, but it doesn't fix the problem: $ . /etc/bash_completion There was even one point in time where it was working for ls, but was not working for cd ... but I can't replicate that result now. Update: I also just discovered that I have terminals open from earlier that still work. I ran source .bashrc in one of them and afterwards completion was broken. Here is my .bashrc: # ~/.bashrc: executed by bash(1) for non-login shells. # see /usr/share/doc/bash/examples/startup-files (in the package bash-doc) # for examples # # Modified by Neil Traft #source ~/.profile # Allow globs to expand hidden files shopt -s dotglob nullglob # If not running interactively, don't do anything [ -z "$PS1" ] && return # don't put duplicate lines or lines starting with space in the history. # See bash(1) for more options HISTCONTROL=ignoreboth # append to the history file, don't overwrite it shopt -s histappend # for setting history length see HISTSIZE and HISTFILESIZE in bash(1) HISTSIZE=1000 HISTFILESIZE=2000 # check the window size after each command and, if necessary, # update the values of LINES and COLUMNS. shopt -s checkwinsize # If set, the pattern "**" used in a pathname expansion context will # match all files and zero or more directories and subdirectories. #shopt -s globstar # make less more friendly for non-text input files, see lesspipe(1) [ -x /usr/bin/lesspipe ] && eval "$(SHELL=/bin/sh lesspipe)" # set variable identifying the chroot you work in (used in the prompt below) if [ -z "$debian_chroot" ] && [ -r /etc/debian_chroot ]; then debian_chroot=$(cat /etc/debian_chroot) fi # Color the prompt export PS1="\[$(tput setaf 2)\]\u@\h:\[$(tput setaf 5)\]\W\[$(tput setaf 2)\] $\[$(tput sgr0)\] " # enable color support of ls and also add handy aliases if [ -x /usr/bin/dircolors ]; then test -r ~/.dircolors && eval "$(dircolors -b ~/.dircolors)" || eval "$(dircolors -b)" alias ls='ls --color=auto' #alias dir='dir --color=auto' #alias vdir='vdir --color=auto' alias grep='grep --color=auto' alias fgrep='fgrep --color=auto' alias egrep='egrep --color=auto' fi # Add an "alert" alias for long running commands. Use like so: # sleep 10; alert alias alert='notify-send --urgency=low -i "$([ $? = 0 ] && echo terminal || echo error)" "$(history|tail -n1|sed -e '\''s/^\s*[0-9]\+\s*//;s/[;&|]\s*alert$//'\'')"' # Alias definitions. # You may want to put all your additions into a separate file like # ~/.bash_aliases, instead of adding them here directly. # See /usr/share/doc/bash-doc/examples in the bash-doc package. if [ -f ~/.bash_aliases ]; then . ~/.bash_aliases fi # enable programmable completion features (you don't need to enable # this, if it's already enabled in /etc/bash.bashrc and /etc/profile # sources /etc/bash.bashrc). if [ -f /etc/bash_completion ] && ! shopt -oq posix; then . /etc/bash_completion fi

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  • When using method chaining, do I reuse the object or create one?

    - by MainMa
    When using method chaining like: var car = new Car().OfBrand(Brand.Ford).OfModel(12345).PaintedIn(Color.Silver).Create(); there may be two approaches: Reuse the same object, like this: public Car PaintedIn(Color color) { this.Color = color; return this; } Create a new object of type Car at every step, like this: public Car PaintedIn(Color color) { var car = new Car(this); // Clone the current object. car.Color = color; // Assign the values to the clone, not the original object. return car; } Is the first one wrong or it's rather a personal choice of the developer? I believe that he first approach may quickly cause the intuitive/misleading code. Example: // Create a car with neither color, nor model. var mercedes = new Car().OfBrand(Brand.MercedesBenz).PaintedIn(NeutralColor); // Create several cars based on the neutral car. var yellowCar = mercedes.PaintedIn(Color.Yellow).Create(); var specificModel = mercedes.OfModel(99).Create(); // Would `specificModel` car be yellow or of neutral color? How would you guess that if // `yellowCar` were in a separate method called somewhere else in code? Any thoughts?

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  • Get to Know a Candidate (5 of 25): Jim Carlson&ndash;Grassroots Party

    - by Brian Lanham
    DISCLAIMER: This is not a post about “Romney” or “Obama”. This is not a post for whom I am voting. Information sourced for Wikipedia. Carlson is an American businessman and the Grassroots Party nominee. Carlson is the owner of Last Place on Earth, a head shop located in Duluth, Minnesota. In September 2011, the shop was raided by police for selling bath salts and synthetic marijuana. After the raid, Carlson filed a lawsuit to strike down Minnesota's ban on the substances. His suit was dismissed by the court in November 2011. The Grassroots Party was created in the 1980s to oppose drug prohibition.  The party shares many of the the political leftist values of the Green Party but with a greater emphasis on marijuana/hemp legalization issues.  The permanent platform of the Grassroots Party is the Bill of Rights. Individual candidate's positions on issues vary from Libertarian to Green. All Grassroots candidates would end marijuana/hemp prohibition and re-legalize Cannabis for all its uses. Learn more about Jim Carlson and Grassroots Party on Wikipedia.

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  • Troubleshooting web timeouts with a Belkin router

    - by rexzilla
    I have a Belkin FSD7632-4 ADSL wifi router. Ever since I got it, I've faced this problem of websites timing out. For example, I go to flickr.com, and the images won't load because they come from farm1.static.flickr.com. Either I wait 10 minutes or so until the timed out sockets are closed and retry (with variable results) or I reboot the router. This happens irrespective of whether I use wired or wifi network. I'm in India, using Airtel Broadband, and if I use my ISP supplied Beetel 220BX ADSL router (which has no wifi and only one LAN port), everything works fine. I copied over the broadband settings from my old router: VPI/VCI values=1/32 Encapsulation=LLC MTU=1492 I have not enabled any firewall on the router. Is there anything else I can try? Or is it a defect with the router and should I take it back for a replacement? I bought it just 2 months ago.

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  • Hanging page loads every n loads

    - by Christian
    Hi Guys I recently moved my site to a new server (Apache 2, PHP5, MySQL5). The site is an Invision based forum. Every few posts / topics it just hangs. The data has been written because if you stop and reload, the post / thread is there. I thought it was a write issue initially, but nope. So, the data is written but the page load never completes. It doesn't leave the page where the data has been input. Whats the best way to trouble shoot this issue? The only thing I have done recently is reduce my MySQL timeouts, but I can't see that being an issue as the values are still big enough and there are no mentions of timeouts in the MySQL log. (For the record there is nothing in PHP's error log either) Thanks in advance!

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  • CentOS default never fsck root partition on start up?

    - by wwwpanda
    Most documentation or sites will say use "tune2fs -l " to check if the system will do fsck on the system partitions on next boot, in particular, should look at "Mount count" and "Maximum mount count" values. However, I notice for default CentOS 5 or 6 installation, when I check against the root partition, I always noticed something like this from tune2fs output: ... Mount count: 91 Maximum mount count: -1 Last checked: Thu Oct 29 18:48:14 2009 Check interval: 0 (<none>) ... i.e. the max. mount count is set to "-1". That makes me wonder does it mean CentOS (or Red Hat) won't check the root partition at all? I check the fstab, the last number for root partition is still "1" as usual. If the OS does fsck the root partition during startup, how can I tell when (i.e. after how many reboots or when) will the OS will start fsck the root parition during startup?

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  • Getting "-bash: fork: Resource temporarily unavailable" in OSX

    - by Joseph Tura
    I seem to run into problems with the max. number of processes every so often. Anyone know what is best practice for fixing this? Running OSX 10.6 on a MacBook Pro i7. ulimit -a returns these values: core file size (blocks, -c) 0 data seg size (kbytes, -d) unlimited file size (blocks, -f) unlimited max locked memory (kbytes, -l) unlimited max memory size (kbytes, -m) unlimited open files (-n) 256 pipe size (512 bytes, -p) 1 stack size (kbytes, -s) 8192 cpu time (seconds, -t) unlimited max user processes (-u) 266 virtual memory (kbytes, -v) unlimited When the error occurred I checked, and there were 102 running tasks and 523 threads.

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  • Apache: domains working fine, subdomains not working anymore

    - by David Lawson
    Hi there, I'm not sure when, but suddenly subdomains aren't working on my server. e.g. www.davidlawson.co works, but david.lawson.co isn't working. <VirtualHost 173.203.109.191:80> ServerAdmin [email protected] ServerName david.lawson.co ServerAlias davidlawson.co ServerAlias www.davidlawson.co DocumentRoot /var/www/lawson/david <Directory /var/www/lawson/david/> Options -Indexes FollowSymLinks MultiViews AllowOverride All Order allow,deny allow from all </Directory> ErrorLog /var/log/apache2/lawson/david/error.log # Possible values include: debug, info, notice, warn, error, crit, # alert, emerg. LogLevel warn CustomLog /var/log/apache2/lawson/david/access.log combined </VirtualHost> Any suggestions on how to debug this further, or what the problem might be?

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  • Why binding is not a native feature in most of the languages?

    - by Gulshan
    IMHO binding a variable to another variable or an expression is a very common scenario in mathematics. In fact, in the beginning, many students think the assignment operator(=) is some kind of binding. But in most of the languages, binding is not supported as a native feature. In some languages like C#, binding is supported in some cases with some conditions fulfilled. But IMHO implementing this as a native feature was as simple as changing the following code- int a,b,sum; sum := a + b; a = 10; b = 20; a++; to this- int a,b,sum; a = 10; sum = a + b; b = 20; sum = a + b; a++; sum = a + b; Meaning placing the binding instruction as assignments after every instruction changing values of any of the variable contained in the expression at right side. After this, trimming redundant instructions (or optimization in assembly after compilation) will do. So, why it is not supported natively in most of the languages. Specially in the C-family of languages? Update: From different opinions, I think I should define this proposed "binding" more precisely- This is one way binding. Only sum is bound to a+b, not the vice versa. The scope of the binding is local. Once the binding is established, it cannot be changed. Meaning, once sum is bound to a+b, sum will always be a+b. Hope the idea is clearer now. Update 2: I just wanted this P# feature. Hope it will be there in future.

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  • How do you write a "nested IF formula" in Excel?

    - by Mike
    I manually enter numbers on one cell according to text values in the cell adjacent to it. Is there a way to use the IF function to help me manage this? The text is automatically generated with a report but I put the numbers in manually in Excel. Example of my weekly boredom below: number Text in Cell 3 Order A 3 Order A 1 Order C 2 Order B 3 Order A 1 Order C 2 Order B 2 Order B HELP! My eyes and soul hurt each time I need to do this. Thanks Mike

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  • Good default for XDG_RUNTIME_DIR?

    - by cadrian
    The XDG Base Directory Specification is a very interesting spec for user directories. It also provides good default values, except for XDG_RUNTIME_DIR. Now I am writing a software that needs to create named pipes. It is a per-user client-server framework (there is a FIFO for the server and a FIFO per client). If XDG_RUNTIME_DIR is not defined, I am currently using a per-user subdirectory in /tmp — but it does not ensure all the specified conditions (viz. the paragraph starting with "The lifetime of the directory MUST be bound to the user being logged in…") Is /tmp/myserver-$USER good enough? Edit I saw elsewhere a few suggestions: . is quite unsatisfactory (at least because it is not an absolute path). I also saw /var/run/user/$USER — not bad, but that directory does not exist (at least on my box running a Debian testing)

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  • Excel: Is it possible to have rows with sub-totals that doesn't ruin the total-total?

    - by Svish
    I have an excel sheet which looks something like this: date text value other-value date text value other-value date text value other-value date text value other-value totals sum other-sum The sum is of course a sum of all the values above it. What I am wondering is if there is a way I can add rows with a sub-total at random places through out that list. For example if I would like to have a sub-total for each new month. My problem is of course that the total sum will become way to large because it will also sum the rows with the sub-totals. Does Excel have a feature that can help me so I can have the sub-totals and a correct total-total? I'm using Excel 2010.

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  • Vim and mouse with ssh from Mac to Linux

    - by Jonatan Littke
    Hey. I certainly know it's possible to make the mouse work in Vim on a remote session to a Linux machine from my Mac, but I haven't figured out just how. Daily vim gives a tip on making it work but if I try to set 'mac-ansi', for example, I get an error saying I can only specify values beginning with builtin_ (riscos, beos-ansi, etc). I've tried using ssh -X, combined with set mouse=a and set term=builtin_anso for example, but with no success with or without combining them. I'm using Snow Leopard and attempting to use the mouse on a Debian machine with vim 7.1.314. I've had a look at the documentation but can't make it work. Any tips?

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  • C# Adds Optional and Named Arguments

    Earlier this month Microsoft released Visual Studio 2010, the .NET Framework 4.0 (which includes ASP.NET 4.0), and new versions of their core programming languages: C# 4.0 and Visual Basic 10. In designing the latest versions of C# and VB, Microsoft has worked to bring the two languages into closer parity. Certain features available in C# were missing in VB, and vice-a-versa. Last week I wrote about Visual Basic 2010's language enhancements, which include implicit line continuation, auto-implemented properties, and collection initializers - three useful features that were available in previous versions of C#. Similarly, C# 4.0 introduces new features to the C# programming language that were available in earlier versions of Visual Basic, namely optional arguments and named arguments. Optional arguments allow developers to specify default values for one or more arguments to a method. When calling such a method, these optional arguments may be omitted, in which case their default value is used. In a nutshell, optional arguments allow for a more terse syntax for method overloading. Named arguments, on the other hand, improve readability by allowing developers to indicate the name of an argument (along with its value) when calling a method. This article examines how to use optional arguments and named arguments in C# 4.0. Read on to learn more! Read More >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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  • C# Adds Optional and Named Arguments

    Earlier this month Microsoft released Visual Studio 2010, the .NET Framework 4.0 (which includes ASP.NET 4.0), and new versions of their core programming languages: C# 4.0 and Visual Basic 10. In designing the latest versions of C# and VB, Microsoft has worked to bring the two languages into closer parity. Certain features available in C# were missing in VB, and vice-a-versa. Last week I wrote about Visual Basic 2010's language enhancements, which include implicit line continuation, auto-implemented properties, and collection initializers - three useful features that were available in previous versions of C#. Similarly, C# 4.0 introduces new features to the C# programming language that were available in earlier versions of Visual Basic, namely optional arguments and named arguments. Optional arguments allow developers to specify default values for one or more arguments to a method. When calling such a method, these optional arguments may be omitted, in which case their default value is used. In a nutshell, optional arguments allow for a more terse syntax for method overloading. Named arguments, on the other hand, improve readability by allowing developers to indicate the name of an argument (along with its value) when calling a method. This article examines how to use optional arguments and named arguments in C# 4.0. Read on to learn more! Read More >

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  • Duck checker in Python: does one exist?

    - by elliot42
    Python uses duck-typing, rather than static type checking. But many of the same concerns ultimately apply: does an object have the desired methods and attributes? Do those attributes have valid, in-range values? Whether you're writing constraints in code, or writing test cases, or validating user input, or just debugging, inevitably somewhere you'll need to verify that an object is still in a proper state--that it still "looks like a duck" and "quacks like a duck." In statically typed languages you can simply declare "int x", and anytime you create or mutate x, it will always be a valid int. It seems feasible to decorate a Python object to ensure that it is valid under certain constraints, and that every time that object is mutated it is still valid under those constraints. Ideally there would be a simple declarative syntax to express "hasattr length and length is non-negative" (not in those words. Not unlike Rails validators, but less human-language and more programming-language). You could think of this as ad-hoc interface/type system, or you could think of it as an ever-present object-level unit test. Does such a library exist to declare and validate constraint/duck-checking on Python-objects? Is this an unreasonable tool to want? :) (Thanks!) Contrived example: rectangle = {'length': 5, 'width': 10} # We live in a fictional universe where multiplication is super expensive. # Therefore any time we multiply, we need to cache the results. def area(rect): if 'area' in rect: return rect['area'] rect['area'] = rect['length'] * rect['width'] return rect['area'] print area(rectangle) rectangle['length'] = 15 print area(rectangle) # compare expected vs. actual output! # imagine the same thing with object attributes rather than dictionary keys.

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  • Practical considerations for HTML / CSS naming conventions (syntax)

    - by Jeroen
    Question: what are the practical considerations for the syntax in class and id values? Note that I'm not asking about the semantics, i.e. the actual words that are being used, as for example described in this blogpost. There are a lot of resources on that side of naming conventions already, in fact obscuring my search for practical information on the various syntactical bits: casing, use of interpunction (specifically the - dash), specific characters to use or avoid, etc. To sum up the reasons I'm asking this question: The naming restrictions on id and class don't naturally lead to any conventions The abundance of resources on the semantic side of naming conventions obscure searches on the syntactic considerations I couldn't find any authorative source on this There wasn't any question on SE Programmers yet on this topic :) Some of the conventions I've considered using: UpperCamelCase, mainly as a cross-over habit from server side coding lowerCamelCase, for consistency with JavaScript naming conventions css-style-classes, which is consistent with naming of css properties (but can be annoying when Ctrl+Shift+ArrowKey selection of text) with_under_scores, which I personally haven't seen used much alllowercase, simple to remember but can be hard to read for longer names UPPERCASEFTW, as a great way to annoy your fellow programmers (perhaps combined with option 4 for readability) And probably I've left out some important options or combinations as well. So: what considerations are there for naming conventions, and to which convention do they lead?

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  • Huge procedurally generated 'wilderness' worlds

    - by The Communist Duck
    Hi. I'm sure you all know of games like Dwarf Fortress - massive, procedural generated wilderness and land. Something like this, taken from this very useful article. However, I was wondering how I could apply this to a much larger scale; the scale of Minecraft comes to mind (isn't that something like 8x the size of the Earth's surface?). Pseudo-infinite, I think the best term would be. The article talks about fractal perlin noise. I am no way an expert on it, but I get the general idea (it's some kind of randomly generated noise which is semi-coherent, so not just random pixel values). I could just define regions X by X in size, add some region loading type stuff, and have one bit of noise generating a region. But this would result in just huge amounts of islands. On the other extreme, I don't think I can really generate a supermassive sheet of perlin noise. And it would just be one big island, I think. I am pretty sure Perlin noise, or some noise, would be the answer in some way. I mean, the map is really nice looking. And you could replace the ascii with tiles, and get something very nice looking. Anyone have any ideas? Thanks. :D -TheCommieDuck

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