https://github.com/c3d/xl-c

A re-implementation of the XL programming language in straight C
https://github.com/c3d/xl-c

Last synced: about 1 year ago
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A re-implementation of the XL programming language in straight C

• Host: GitHub
• URL: https://github.com/c3d/xl-c
• Owner: c3d
• License: gpl-3.0
• Created: 2017-05-14T07:41:40.000Z (about 9 years ago)
• Default Branch: master
• Last Pushed: 2019-04-11T19:53:24.000Z (about 7 years ago)
• Last Synced: 2025-03-30T07:41:14.172Z (about 1 year ago)
• Language: C
• Size: 204 KB
• Stars: 4
• Watchers: 2
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

          
# XL

### An extensible programming language

XL is a very simple and small programming language specifically

designed to be integrated in larger projects.

XL is also a somewhat special language because it is minimalistic yet

usable. It was designed to be extensible by programmers, and as a

result, most of the features that you expect to be built-ins in most

languages (like control or data structures) are really defined by the

library in XL. As a matter of fact, XL is defined using a *single*

operator.

## The magic rewrite operator

The rewrite operator in XL is written `->`. Something like `A -> B`

reads as *if you see A in a program, rewrite it as B*. Depending on

the context, this rewrite operators can be used to define:

* Variables

          X -> 0

     

* Functions

          distance A, B -> sqrt((B-A)^2)

* Functions can be defined using special cases and recursion

          0! -> 1

          N! -> N * (N-1)!

 

* Operators, which can also include special cases

          0 + B -> B

          A + 0 -> A

          A + B -> (A-1) + (B+1)

     

* Combinations of operators

          A in B..C -> A >= B and A <= C

* Control structures

          loop Body -> Body; loop Body

          if true then TrueBody else FalseBody -> TrueBody

          if false then TrueBody else FalseBody -> FalseBody

          while Condition loop Body ->

              if Condition then

                  Body

                  while Condition loop Body

## Field-tested

XL was field-tested at a relatively large scale in the Tao3D project, where

it serves as a dynamic document description language for a real-time

3D rendering engine. XL also serves as the foundation for ELFE, which

is a version of XL indented to allow quick experiments with the Internet

of things.

## Under re-construction

It is based on these experiences that the current rewrite is taking

place. The new implementation will take advantage of several years of

experience with the older implementations. It will be written in C,

rely on LLVM only as an option, if ever, and should be noticeably

faster.

For the moment, this new implementation does not work at all, though.