rusty_scheme's Introduction

RustyScheme

A toy Scheme interpreter written in Rust, loosely based on the R5RS Specification with a bit of Racket thrown in as well.

It supports a small number of standard library functions, as well as:

Function and variable definition
Quote, Quasiquote/unquote
Apply & Eval
Macros (not hygenic yet)
Let expressions
Tail-call optimization
Continuations, Call-with-current-continuation
Unicode
REPL, with history

There are two versions of the interpreter:

A straight-forward AST-walking interpreter, which uses the Rust stack and heap, and uses vectors to represent Scheme lists.
A continuation-passing style interpreter, which supports tail-call optimization and continuations, uses the Rust stack and heap, and uses a linked list to represent Scheme lists.

In the future, I may develop an interpreter that manages its own stack and/or heap, and possibly a bytecode VM & compiler as well for comparison.

Requirements

Rust 1.0-beta or later

Usage

Download and install Rust 1.0 from http://www.rust-lang.org/install.html.

To start a REPL using the default CPS interpreter:

cargo run

To execute a Scheme file using the default CPS interpreter:

cargo run examples/printing.scm

To start a REPL using the AST-walking interpreter:

cargo run -- -t ast_walk

To execute a Scheme file using the AST-walking interpreter:

cargo run -- -t ast_walk examples/printing.scm

To run the test suite:

cargo test

To watch for changes and auto-rebuild (on OS X):

gem install kicker -s http://gemcutter.org
./watch

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rusty_scheme's Issues

getopts complier error

this is an error in getopts library, not rusty_scheme, but it breaks this build so...

After:

git clone https://github.com/kenpratt/rusty_scheme.git
cd rusty_scheme
cargo run

This is the error I get ...

$ cargo run
   Compiling getopts v0.2.11
error[E0503]: cannot use `state` because it was mutably borrowed
   --> /home/sean/.cargo/registry/src/github.com-1ecc6299db9ec823/getopts-0.2.11/src/lib.rs:974:33
    |
921 |     let mut machine = |cont: &mut bool, (i, c): (usize, char)| {
    |                       ---------------------------------------- borrow of `state` occurs here
...
925 |         state = match (state, whitespace, limit) {
    |         ----- borrow occurs due to use of `state` in closure
...
974 |     while cont && match state { B | C => true, A => false } {
    |                                 ^ use of borrowed `state`
975 |         machine(&mut cont, (fake_i, ' '));
    |         ------- borrow later used here

For more information about this error, try `rustc --explain E0503`.
error: could not compile `getopts` due to previous error