CPAN is a Perl tool for installing and managing modules. CPAN stands for the Comprehensive Perl Archive Network. There are many mirrors around the world that host the same CPAN archive. Sometimes mirrors shut down or you may want to add mirrors that are closer to you. These examples demonstrate how to add and remove mirrors from your configuration.
Standard in and Standard out (STDIN/STDOUT) are very common methods of interacting with the user. Standard in is typically the keyboard and standard out is the terminal. Haskell makes this very easy to access. The getLine function gets a value from the user and putStrLn and putStr allow you to write to output. The ++ operator is used to concatenate strings.
In Haskell, you can access the command line arguments with getArgs. Check out this example.
Haskell is a purely functional programming language create in 1990. This Hello World example will help you get started with Haskell. Install Haskell for your system from the Haskell website. The program installed is called ghc which stands for the Glasgow Haskell Compiler. It can be run interactively or as a compiler.
C and Assembly can be used together to provide extra flexibility. You can create static libraries in Assembly that you call from C, and vice-versa, you can call C functions from within Assembly. Check out the code samples below that demonstrate that process.
NASM, or The Netwide Assembler, is an x86 compiler that allows us to turn Assembly code in to machine code object files. Once we have an object file, we can link it and create the final executable. This example is meant for Unix systems or Windows with MinGW toolchain installed. On Debian systems, it can be installed with the nasm package. Put the code below in to hello.asm
Scala programs can accept run-time variables as command line arguments. Here is an example of how to access the variables.
Scala provides some of its own libraries for IO, but we can also make use of the Java library. The example of reading a file uses Scala's IO package, but the file writing example uses the Java IO package.
Scala is a an object oriented functional language built on top of the Java Virtual Machine. (JVM). Because it is an extension of Java, you still have everything available to you as you normally would in Java. Check out this Hello World example.
Control structures like if/else statements, for loops, and switch cases are vital to writing program logic. These code snippets will serve as easy references for these control structures when writing with the Tcl programming language