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extern crate mal;
use std::collections::HashMap;
use mal::types::{MalVal, MalRet, MalError, err_str, err_string};
use mal::types::{list, vector, hash_map, _int, func};
use mal::types::MalError::{ErrString, ErrMalVal};
use mal::types::MalType::{Sym, List, Vector, Hash_Map, Int};
use mal::{readline, reader};
// 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.get(sym) {
Some(mv) => Ok(mv.clone()),
//None => Ok(_nil()),
None => err_string(format!("'{}' not found", sym)),
}
},
List(ref a,_) | Vector(ref a,_) => {
let mut ast_vec : Vec<MalVal> = vec![];
for mv in a.iter() {
let mv2 = mv.clone();
ast_vec.push(try!(eval(mv2, env)));
}
Ok(match *ast { List(_,_) => list(ast_vec),
_ => vector(ast_vec) })
}
Hash_Map(ref hm,_) => {
let mut new_hm: HashMap<String,MalVal> = HashMap::new();
for (key, value) in hm.iter() {
new_hm.insert(key.to_string(),
try!(eval(value.clone(), env)));
}
Ok(hash_map(new_hm))
}
_ => Ok(ast.clone()),
}
}
fn eval(ast: MalVal, env: &HashMap<String,MalVal>) -> MalRet {
//println!("eval: {}", ast);
match *ast {
List(_,_) => (), // continue
_ => return eval_ast(ast, env),
}
// apply list
match *try!(eval_ast(ast, env)) {
List(ref args,_) => {
let ref f = args.clone()[0];
f.apply(args[1..].to_vec())
},
_ => return err_str("Expected list"),
}
}
// print
fn print(exp: MalVal) -> String {
exp.pr_str(true)
}
fn rep(str: &str, env: &HashMap<String,MalVal>) -> Result<String,MalError> {
let ast = try!(read(str.to_string()));
//println!("read: {}", ast);
let exp = try!(eval(ast, env));
Ok(print(exp))
}
fn int_op<F>(f: F, a:Vec<MalVal>) -> MalRet
where F: FnOnce(isize, isize) -> isize
{
match *a[0] {
Int(a0) => match *a[1] {
Int(a1) => Ok(_int(f(a0,a1))),
_ => err_str("second arg must be an int"),
},
_ => err_str("first arg must be an int"),
}
}
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(ErrMalVal(_)) => (), // Blank line
Err(ErrString(s)) => println!("Error: {}", s),
}
}
}
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