bs - A Basic Scheme Implementation
==================================
bs is an interpreter for a simple Scheme-like language. It lacks the more
advanced features of Scheme, such as macros and call/cc.
The goal of bs is to implement enough of Scheme to boostrap a Scheme compiler
written in Scheme. A secondary goal is to learn about writing simple
interpreters.
This project was inspired by Peter Michaux's "Scheme from Scratch" project.
https://peter.michaux.ca/articles/scheme-from-scratch-introduction
Usage
=====
./bs file [-p]
Where "file" is either a Scheme source file, or a "-" to read from stdin.
"-p" causes bs to print the result of every expression it evaluated.
There is a read-eval-print loop in the file bsrepl.scm. To use it, just run
"./bs bsrepl.scm"
Features Implemented
====================
Data types:
    integers
    booleans
    characters
    strings
    pairs and lists
    ports
Special Forms:
    quote and '
    define
    set!
    if
    cond
    lambda
    let
    begin
    and
    or
Primitives:
    eq?
    null?
    boolean?
    symbol?
    integer?
    char?
    string?
    pair?
    list?
    procedure?
    input-port?
    output-port?
    eof-object?
    +
    -
    *
    quotient
    remainder
    =
    <
    >
    cons
    car
    set-car!
    cdr
    set-cdr!
    length
    list
    char->integer
    integer->char
    number->string
    string->number
    symbol->string
    string->symbol
    current-input-port
    current-output-port
    open-input-file
    open-output-file
    close-input-port
    close-output-port
    read
    read-char
    write
    write-char
    display
    stdin-port
    stdout-port
    load
    error
    apply
    eval
    interaction-environment
    null-environment
    environment
In stdlib.scm:
    number?
    map
    for-each
    fold-right
    fold-left
    reverse
    append
    not
    newline
    call-with-input-file
    call-with-output-file
    caar, cddr, etc.
Compilation
============
To build bs, you'll need libgc and scons. Assuming you already have gcc
installed, you can install the neccessary packages on a Debian-based system
with this command:
    $ sudo apt-get install libgc-dev scons
Then type "scons" in the project directory to build bs.
If you are using a non-Debian-based system, or a different compiler, you'll
probably need to edit the SConstruct file.
There is a simple test script in the tests/ directory. Look at the comments at
the top of run-tests.sh for details.
See the LICENSE file for copyright and licensing information.