XP Language experiment

This is the XP language - a compiled programming language built on top of the XP Framework and written using it; inspired and still close to PHP but also with elements from the Java and C# worlds. At the same time, this experiment also proves how PHP can be used as a platform, with different possible input syntaxes generating intermediate code to run inside it, and be able to re-use code written in other syntaxes but also plain old PHP, but sharing the XP Framework's foundation classes as a common SDK.

Overview

Here's a list of the subdirectories inside this one and what you will find inside: 

  - tests   : Unittests
  - cmd     : Utility xpclis
  - demo    : Examples
  - grammar : Grammars
  - xp      : Implementation

Motivation

Designing the XP programming language we had the following goals in mind:

  • Get rid of the oddities in PHP - alternative syntaxes like if / endif for example or "__"-magic.
  • Overcome limitations in the PHP grammar that do not allow chaining at all points like method calls after new() and array access after method calls.
  • Support syntactically what the XP framework has built ontop of PHP: annotations, type-safe enums, return types, thrown exceptions, finallly, with() blocks.
  • Integrate with the XP Framework's foundation classes.
  • Keep the "change and run" spirit and the ability for rapid development.
Generally speaking, we've tried to follow the "less is more" principle and tried making the syntax more concise as to what it's doing.

Prerequisites

This experiment requires XP Framework version 5.8.0-dev plus the classes from this directory. Replace the "use" line in your xp.ini with the following:

  use=~/devel/xp/branches/xp5_8;~/devel/xp.forge/trunk/experiments/arena/lang

Getting started

Like in the XP framework, the entry point is always a class. In their most simple form, these classes have a static main() method. An example:

  public class HelloWorld {
    public static void main(string[] $args) {
      util.cmd.Console::writeLine('Hello World from ', self::$class.getName(), '!');
    }
  }

Now you will already start noticing things:

  • Classes may also have modifiers.
  • The "extends Object" is optional and added by the compiler if omitted.
  • The keyword "function" is gone and replaced by the return type. Because the main() method does not return anything, we use "void".
  • An array type is written as component[]
  • Variables still have dollar signs. This makes it easy to spot them, that's why we've decided to keep this!
  • Fully qualified classnames are written with dots.
  • The object operator is also a dot (at the same time, the string concatenation operator is now the tilde, ~).
This is not everything though, to get an impression on the language's "look and feel" have a look at the examples in the demo subdirectory.

Try it!

Compile: 

  $ xcc demo/HelloWorld.xp

Run: 

  $ xp HelloWorld



Hacking

When changing the grammar file you need to regenerate the parser: 

  $ make grammar



Elements

demo
grammar
lib
src
compiler.pth2010-03-22 08:47:29+0100
Makefile2010-03-22 08:47:29+0100
README2010-03-22 08:47:29+0100

Table of contents

Arena
People