Haskeme

Haskeme is a Lisp interpreter written in Haskell. It's very much a work-in-progress, as well as a way for me to experiment with new ideas and syntax. The skeleton of the interpreter is based on the excellent tutorial found at:

• http://en.wikibooks.org/wiki/Write_Yourself_a_Scheme_in_48_Hours/First_Steps

I've also borrowed some ideas from Arc and Q:

• http://ycombinator.com/arc/tut.txt
• http://en.wikipedia.org/wiki/Q_(programming_language_from_Kx_Systems)

Features

• Data types
  • Symbol, Pair, Char, String, Boolean
  • Full numeric tower (Integer, Rational, Float, Complex)
  • Vectors
  • Hashes
  • Procedures
• Control flow
  • Conditionals (if, case, when)
  • Statement grouping with do
• Scope
  • Top-level definitions with def
  • Local bindings with let and with
• Assignment
  • Assignment using = operator
  • Assignment reaches inside structures: (= (car x) 1)
  • Set elements of strings, vectors and hashes: (= (vec 0) 1)
• Functions:
  • User defined functions, lambdas (with fn keyword) and lexical closures
  • Notation for unary functions: [+ _ 1]
  • Full suite of numeric functions (trigonometry, sqrt, exp/log etc)
  • Basic random number generation with random
  • Can call strings, vectors and hashes as if they were functions: (vec 0) etc.
• I/O
  • Read/write to stdin/stdout or any file
  • Load libraries from a file
• Flexible macro system:
  • Whole language, including user defined functions, available at macro expansion time
• Standard library

Still to come

• Tail call optimization
• Continuations
• Compiler
• Random numbers
• Streams (lazy lists)