Stackd is a concatenative programming language, much like Factor and Forth.
It’s somewhat an attempt to write a Factor implementation in Ruby.
In contrast to Factor, Stackd is interpreted and not compiled.
It’s still in an early development phase, so many things aren’t yet supported.

Here’s a small list of features, that currently work already:

• Word definitions
  
• Most of Factors core words
  (still some missing, but shouldn’t be hard to implement)
  
• Literals for
  
  • Booleans
    
  • Numbers (Integer & Float)
    
  • Strings
    
  • Arrays
    
  • Symbols (as in Ruby)
    
  • Quotations (e.g. first-class ‘functions’)
    
  • Regular Expressions (as in Ruby)
    
  • Hashtables (as in Ruby)
    
• Two stacks to work with:
  
  • Data stack
    (used implicitly and most of the time)
    
  • Retain stack
    (used for temporarily storing values with predefined words
    e.g.: dip, keep etc.)
    
• Very lean and simple syntax (as in Factor)
  
• A simple REPL (see bin/repl)
  
• Support for debug output via: bin/stackd filename.stackd —debug
  –> Outputs the parsed AST

What’s partially implemented:

• A generic object system (as in Factor)
  
• Support for:
  
  • Generic Words & Methods
    
  • Inheritance
    

What’s still missing (and never might be implemented):

• Private / read-only slots on objects / classes (and probably more)
  
• Nice development tools, as Factor has them
  
• Real debugger or walker
  
• Many more features, you’ll find in Factor

Some basic syntax rules:

• All expressions / statements need to end with a semicolon (‘;’)
  
• Word definitions start with a colon (‘:’)
  
• Words can be named almost anything (as in Factor)
  e.g.: <>, <a,b>, empty?, >!< etc.
  
• For more information, have a look at:
  http://concatenative.org/

Example code:
* You can find some example code within the examples/ directory.

————– Dependencies ————–

• Treetop for the parser:
  http://treetop.rubyforge.org

—————– License ——————
Stackd is licensed under the GNU GPL v3.
It is heavily influenced by the Factor programming language.
Factor is © Slava Pestov. Some parts of Stackd’s core library
is taken from Factor’s.
See http://www.factorcode.org for more information about Factor.

For more information on copying & distribution take a look at the
LICENSE file.

© 2009 Christopher Bertels
http://www.adztec-independent.de