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extern crate mal;
use std::collections::HashMap;
use mal::types::{MalVal, MalRet, MalError, err_str};
use mal::types::{symbol, _int, list, vector, hash_map, func};
use mal::types::MalError::{ErrString, ErrMalVal};
use mal::types::MalType::{Int, Sym, List, Vector, Hash_Map};
use mal::{readline, reader};
use mal::env::{Env, env_new, env_set, env_get};
// read
fn read(str: String) -> MalRet {
reader::read_str(str)
}
// eval
fn eval_ast(ast: MalVal, env: Env) -> MalRet {
match *ast {
Sym(_) => env_get(&env, &ast),
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.clone())));
}
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.clone())));
}
Ok(hash_map(new_hm))
}
_ => Ok(ast.clone()),
}
}
fn eval(ast: MalVal, env: Env) -> MalRet {
//println!("eval: {}, {}", ast, env.borrow());
//println!("eval: {}", ast);
match *ast {
List(_,_) => (), // continue
_ => return eval_ast(ast, env),
}
// apply list
match *ast {
List(_,_) => (), // continue
_ => return Ok(ast),
}
let tmp = ast;
let (args, a0sym) = match *tmp {
List(ref args,_) => {
if args.len() == 0 {
return Ok(tmp.clone());
}
let ref a0 = *args[0];
match *a0 {
Sym(ref a0sym) => (args, &a0sym[..]),
_ => (args, "__<fn*>__"),
}
},
_ => return err_str("Expected list"),
};
match a0sym {
"def!" => {
let a1 = (*args)[1].clone();
let a2 = (*args)[2].clone();
let r = try!(eval(a2, env.clone()));
match *a1 {
Sym(_) => {
env_set(&env.clone(), a1, r.clone());
return Ok(r);
},
_ => return err_str("def! of non-symbol"),
}
},
"let*" => {
let let_env = env_new(Some(env.clone()));
let a1 = (*args)[1].clone();
let a2 = (*args)[2].clone();
match *a1 {
List(ref binds,_) | Vector(ref binds,_) => {
let mut it = binds.iter();
while it.len() >= 2 {
let b = it.next().unwrap();
let exp = it.next().unwrap();
match **b {
Sym(_) => {
let r = try!(eval(exp.clone(), let_env.clone()));
env_set(&let_env, b.clone(), r);
},
_ => return err_str("let* with non-symbol binding"),
}
}
},
_ => return err_str("let* with non-list bindings"),
}
return eval(a2, let_env.clone());
},
_ => { // function call
let el = try!(eval_ast(tmp.clone(), env.clone()));
let args = match *el {
List(ref args,_) => args,
_ => return err_str("Invalid apply"),
};
let ref f = args.clone()[0];
f.apply(args[1..].to_vec())
},
}
}
// print
fn print(exp: MalVal) -> String {
exp.pr_str(true)
}
fn rep(str: &str, env: Env) -> 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 repl_env = env_new(None);
env_set(&repl_env, symbol("+"), func(add));
env_set(&repl_env, symbol("-"), func(sub));
env_set(&repl_env, symbol("*"), func(mul));
env_set(&repl_env, symbol("/"), func(div));
// repl loop
loop {
let line = readline::mal_readline("user> ");
match line { None => break, _ => () }
match rep(&line.unwrap(), repl_env.clone()) {
Ok(str) => println!("{}", str),
Err(ErrMalVal(_)) => (), // Blank line
Err(ErrString(s)) => println!("Error: {}", s),
}
}
}
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