Muddy Scheme

Author: pmarin
Please add content only in the Comments , Bugs or News section.

• Introduction
• Features
• Install
• Example of use
• Bugs
• News
• License
• Comments

Introduction

Muddy Scheme is an implementation of the Scheme language in Tcl.

This interpreter tries to follow the awesome "Scheme from Scratch" articles written by Peter Michaux.

Features

• A garbage collector!!!
• Procedures
  • define
  • lambda
  • begin
  • Lexically scoped variables
  • Proper tail calls
• Binding Constructs
  • let
  • let*
• Conditionals
  • cond
  • and
  • or
• Types
  • integers
  • characters
  • pairs
  • strings
  • booleans
• Primitives
  • Type of Predicates
    • not
    • eq?
    • null?
    • boolean?
    • symbol?
    • atom?
    • number?
    • integer?
    • zero?
    • char?
    • string?
    • pair?
    • procedure?
  • Type conversions
    • char->integer
    • integer->char
    • number->string
    • string->number
    • symbol->string
    • string->symbol
  • Working with integers
    • +
    • -
    • *
    • quotient
    • remainder
    • =
    • <
    • >
  • Working with pair and list
    • cons
    • car
    • cdr
    • set-car!
    • set-cdr!
    • list
  • I/O
    • current-output-port
    • open-output-file
    • close-output-port
    • display
    • write
    • newline
    • write-char
    • current-input-port
    • open-input-file
    • close-input-port
    • read-char
    • peek-char
    • eof-object
    • read
  • Others
    • garbage-collect (you can not use it everywhere)
    • apply
    • load
    • exit
    • quit (return to tclsh if you sourced muddy.tcl)
    • tcl-eval

Install

Muddy Scheme needs Tcl8.6 and tcllib (struct::stack)

The Github page is: http://github.com/pmarin/Muddy-Scheme
You can get the code with:

    $ git clone git://github.com/pmarin/Muddy-Scheme.git

Example of use

    $ muddy.tcl
    Welcome to Muddy Scheme, Copyright (c) 2010 Franciso José Marín Pérez
    Use ctrl-c to exit.

    > #t
    #t
    > -123
    123
    > #\c
    #\c
    > "asdf"
    "asdf"
    > (quote ())
    ()
    > (quote (0 . 1))
    (0 . 1)
    > (quote (0 1 2 3))
    (0 1 2 3)
    > (quote asdf)
    asdf
    > (define a 1)
    ok
    > a
    1
    > (set! a 2)
    ok
    > a
    2
    > (if #t 1 2)
    1
    > (+ 1 2 3)
    6
    > + 
    #<primitive>
    >^c
    $

Bugs

News

(2010-2-21) Now the garbage collector is working properly. Use set-mem-limit! for setting the number of object used before the GC. vector and floats are implemented.
(2010-1-25) Added mark-and-sweep garbage collector. Currently It is called always in the REPL and load loop, I need to determinate the size of the process for using it more properly.
(2010-1-24) Almost all I/O procedures
(2010-1-22) Apply and not
(2010-1-22) (V0.17) Added let*. There is a function in debug.scm that print errorInfo:

Welcome to Muddy Scheme, Copyright (c) 2010 Franciso José Marín Pérez
> (load "debug.scm")
#t
> asdf
unbound variable asdf in the environment Env:0
> (error-info)
unbound variable asdf in the environment Env:0
    while executing
"error "unbound variable [$var val] in the environment $_env""
    (class "::Env" method "lookup_variable_value" line 13)
    invoked from within
"$envi lookup_variable_value $exp $env"
    (procedure "_eval" line 13)
    invoked from within
"_eval $str $the_global_environment "
#t

(2010-1-21) (V0.16) Added let, list and tcl-eval. Now is possible to eval tcl code:

> (tcl-eval "puts {Hello Tclers!}" )
Hello Tclers!
#t

(2010-1-20) Added load. Now the REPL is wrapped with catch so if something goes wrong you will remain in the REPL (is a dirty hack but works). Updated to bootstrap-scheme V0.15.
(2010-1-19) Fixed the bug in the reader. Updated to v0.14 and added and & or. Now the interpreter is compliant with "The Little Schemer".
(2010-1-18) Muddy is compliant with bootstrap-scheme v0.14. I need to fix bugs in the reader.

Accumulator Generator:

    >(define (foo n) 
       (lambda (i) 
          (set! n (+ n i)) n))
    >(define acc (foo 3))
    ok
    > (acc 1)
    4
    > (acc 1)
    5 
    > (acc 10)
    15
    > (acc 0)
    15   

(2010-1-17) Muddy is compliant with bootstrap-scheme v0.12
(2010-1-16) Currently the code is compliant with bootstrap-scheme v0.11

License

MIT License
I give permission to wiki users to copy & paste the code in this wiki.

Comments

pmarin. Enjoy!!!