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// support precompiled regexes in reader.rs
#![feature(phase)]
#[phase(plugin)]
extern crate regex_macros;
extern crate regex;
use std::collections::HashMap;
use types::{MalVal,MalRet,Int,Sym,List,Func,
_nil,_int,list,func};
mod readline;
mod types;
mod env;
mod reader;
mod printer;
// read
fn read(str: String) -> MalRet {
reader::read_str(str)
}
// eval
fn eval_ast(ast: MalVal, env: &HashMap<String,MalVal>) -> MalRet {
match *ast {
Sym(ref sym) => {
match env.find_copy(sym) {
Some(mv) => Ok(mv),
None => Ok(_nil()),
}
},
List(ref a) => {
let mut ast_vec : Vec<MalVal> = vec![];
for mv in a.iter() {
let mv2 = mv.clone();
match eval(mv2, env) {
Ok(mv) => { ast_vec.push(mv); },
Err(e) => { return Err(e); },
}
}
Ok(list(ast_vec))
},
_ => {
Ok(ast.clone())
}
}
}
fn eval(ast: MalVal, env: &HashMap<String,MalVal>) -> MalRet {
let ast2 = ast.clone();
match *ast2 {
List(_) => (), // continue
_ => return eval_ast(ast2, env),
}
// apply list
match eval_ast(ast, env) {
Err(e) => Err(e),
Ok(el) => {
match *el {
List(ref args) => {
// TODO: make this work
//match args.as_slice() {
// [&Func(f), rest..] => {
// (*f)(rest.to_vec())
// },
// _ => Err("attempt to call non-function".to_string()),
//}
let args2 = args.clone();
match *args2[0] {
Func(f) => f(args.slice(1,args.len()).to_vec()),
_ => Err("attempt to call non-function".to_string()),
}
}
_ => Err("Invalid apply".to_string()),
}
}
}
}
// print
fn print(exp: MalVal) -> String {
exp.pr_str(true)
}
fn rep(str: String, env: &HashMap<String,MalVal>) -> Result<String,String> {
match read(str) {
Err(e) => Err(e),
Ok(ast) => {
//println!("read: {}", ast);
match eval(ast, env) {
Err(e) => Err(e),
Ok(exp) => Ok(print(exp)),
}
}
}
}
fn int_op(f: |i:int,j:int|-> int, a:Vec<MalVal>) -> MalRet {
match *a[0] {
Int(a0) => match *a[1] {
Int(a1) => Ok(_int(f(a0,a1))),
_ => Err("second arg must be an int".to_string()),
},
_ => Err("first arg must be an int".to_string()),
}
}
fn add(a:Vec<MalVal>) -> MalRet { int_op(|i,j| { i+j }, a) }
fn sub(a:Vec<MalVal>) -> MalRet { int_op(|i,j| { i-j }, a) }
fn mul(a:Vec<MalVal>) -> MalRet { int_op(|i,j| { i*j }, a) }
fn div(a:Vec<MalVal>) -> MalRet { int_op(|i,j| { i/j }, a) }
fn main() {
let mut repl_env : HashMap<String,MalVal> = HashMap::new();
repl_env.insert("+".to_string(), func(add));
repl_env.insert("-".to_string(), func(sub));
repl_env.insert("*".to_string(), func(mul));
repl_env.insert("/".to_string(), func(div));
loop {
let line = readline::mal_readline("user> ");
match line { None => break, _ => () }
match rep(line.unwrap(), &repl_env) {
Ok(str) => println!("{}", str),
Err(str) => println!("Error: {}", str),
}
}
}
|
