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-rw-r--r--rust/src/bin/step5_tco.rs178
1 files changed, 66 insertions, 112 deletions
diff --git a/rust/src/bin/step5_tco.rs b/rust/src/bin/step5_tco.rs
index 4117634..9a2a4ce 100644
--- a/rust/src/bin/step5_tco.rs
+++ b/rust/src/bin/step5_tco.rs
@@ -4,8 +4,8 @@ use std::collections::HashMap;
use mal::types::{MalVal, MalRet, MalError, err_str};
use mal::types::{symbol, _nil, list, vector, hash_map, malfunc};
-use mal::types::MalType::{Nil, False, Sym, List, Vector, Hash_Map, Func, MalFunc};
use mal::types::MalError::{ErrString, ErrMalVal};
+use mal::types::MalType::{Nil, False, Sym, List, Vector, Hash_Map, Func, MalFunc};
use mal::{readline, reader, core};
use mal::env::{env_set, env_get, env_new, env_bind, Env};
@@ -17,35 +17,26 @@ fn read(str: String) -> MalRet {
// eval
fn eval_ast(ast: MalVal, env: Env) -> MalRet {
- let ast2 = ast.clone();
- match *ast2 {
- //match *ast {
+ 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();
- match eval(mv2, env.clone()) {
- Ok(mv) => { ast_vec.push(mv); },
- Err(e) => { return Err(e); },
- }
+ 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() {
- match eval(value.clone(), env.clone()) {
- Ok(mv) => { new_hm.insert(key.to_string(), mv); },
- Err(e) => return Err(e),
- }
+ new_hm.insert(key.to_string(),
+ try!(eval(value.clone(), env.clone())));
}
Ok(hash_map(new_hm))
- },
- _ => {
- Ok(ast)
}
+ _ => Ok(ast.clone()),
}
}
@@ -54,23 +45,22 @@ fn eval(mut ast: MalVal, mut env: Env) -> MalRet {
//println!("eval: {}, {}", ast, env.borrow());
//println!("eval: {}", ast);
- let ast2 = ast.clone();
- let ast3 = ast.clone();
- match *ast2 {
+ match *ast {
List(_,_) => (), // continue
- _ => return eval_ast(ast2, env),
+ _ => return eval_ast(ast, env),
}
// apply list
- match *ast2 {
+ match *ast {
List(_,_) => (), // continue
- _ => return Ok(ast2),
+ _ => return Ok(ast),
}
- let (args, a0sym) = match *ast2 {
+ let tmp = ast;
+ let (args, a0sym) = match *tmp {
List(ref args,_) => {
if args.len() == 0 {
- return Ok(ast3);
+ return Ok(tmp.clone());
}
let ref a0 = *args[0];
match *a0 {
@@ -85,20 +75,13 @@ fn eval(mut ast: MalVal, mut env: Env) -> MalRet {
"def!" => {
let a1 = (*args)[1].clone();
let a2 = (*args)[2].clone();
- let res = eval(a2, env.clone());
- match res {
- Ok(r) => {
- match *a1 {
- Sym(_) => {
- env_set(&env.clone(), a1.clone(), r.clone());
- return Ok(r);
- },
- _ => {
- return err_str("def! of non-symbol")
- }
- }
+ let r = try!(eval(a2, env.clone()));
+ match *a1 {
+ Sym(_) => {
+ env_set(&env.clone(), a1, r.clone());
+ return Ok(r);
},
- Err(e) => return Err(e),
+ _ => return err_str("def! of non-symbol"),
}
},
"let*" => {
@@ -113,18 +96,10 @@ fn eval(mut ast: MalVal, mut env: Env) -> MalRet {
let exp = it.next().unwrap();
match **b {
Sym(_) => {
- match eval(exp.clone(), let_env.clone()) {
- Ok(r) => {
- env_set(&let_env, b.clone(), r);
- },
- Err(e) => {
- return Err(e);
- },
- }
- },
- _ => {
- return err_str("let* with non-symbol binding");
+ let r = try!(eval(exp.clone(), let_env.clone()));
+ env_set(&let_env, b.clone(), r);
},
+ _ => return err_str("let* with non-symbol binding"),
}
}
},
@@ -136,71 +111,55 @@ fn eval(mut ast: MalVal, mut env: Env) -> MalRet {
},
"do" => {
let el = list(args[1..args.len()-1].to_vec());
- match eval_ast(el, env.clone()) {
- Err(e) => return Err(e),
- Ok(_) => {
- let ref last = args[args.len()-1];
- ast = last.clone();
- continue 'tco;
- },
- }
+ try!(eval_ast(el, env.clone()));
+ ast = args[args.len() - 1].clone();
+ continue 'tco;
},
"if" => {
let a1 = (*args)[1].clone();
- let cond = eval(a1, env.clone());
- match cond {
- Err(e) => return Err(e),
- Ok(c) => match *c {
- False | Nil => {
- if args.len() >= 4 {
- let a3 = (*args)[3].clone();
- ast = a3;
- env = env.clone();
- continue 'tco;
- } else {
- return Ok(_nil());
- }
- },
- _ => {
- let a2 = (*args)[2].clone();
- ast = a2;
- env = env.clone();
+ let c = try!(eval(a1, env.clone()));
+ match *c {
+ False | Nil => {
+ if args.len() >= 4 {
+ ast = args[3].clone();
continue 'tco;
- },
- }
+ } else {
+ return Ok(_nil());
+ }
+ },
+ _ => {
+ ast = args[2].clone();
+ continue 'tco;
+ },
}
},
"fn*" => {
- let a1 = (*args)[1].clone();
- let a2 = (*args)[2].clone();
- return Ok(malfunc(eval, a2, env.clone(), a1, _nil()));
+ let a1 = args[1].clone();
+ let a2 = args[2].clone();
+ return Ok(malfunc(eval, a2, env, a1, _nil()));
},
_ => { // function call
- return match eval_ast(ast3, env.clone()) {
- Err(e) => Err(e),
- Ok(el) => {
- let args = match *el {
- List(ref args,_) => args,
- _ => return err_str("Invalid apply"),
- };
- match *args.clone()[0] {
- Func(f,_) => f(args[1..].to_vec()),
- MalFunc(ref mf,_) => {
- let mfc = mf.clone();
- let alst = list(args[1..].to_vec());
- let new_env = env_new(Some(mfc.env.clone()));
- match env_bind(&new_env, mfc.params, alst) {
- Ok(_) => {
- ast = mfc.exp;
- env = new_env;
- continue 'tco;
- },
- Err(e) => err_str(&e),
- }
+ let el = try!(eval_ast(tmp.clone(), env.clone()));
+ let args = match *el {
+ List(ref args,_) => args,
+ _ => return err_str("Invalid apply"),
+ };
+ return match *args.clone()[0] {
+ Func(f,_) => f(args[1..].to_vec()),
+ MalFunc(ref mf,_) => {
+ let mfc = mf.clone();
+ let alst = list(args[1..].to_vec());
+ let new_env = env_new(Some(mfc.env.clone()));
+ match env_bind(&new_env, mfc.params, alst) {
+ Ok(_) => {
+ ast = mfc.exp;
+ env = new_env;
+ continue 'tco;
},
- _ => err_str("attempt to call non-function"),
+ Err(e) => err_str(&e),
}
- }
+ },
+ _ => err_str("attempt to call non-function"),
}
},
}
@@ -214,16 +173,10 @@ fn print(exp: MalVal) -> String {
}
fn rep(str: &str, env: Env) -> Result<String,MalError> {
- match read(str.to_string()) {
- Err(e) => Err(e),
- Ok(ast) => {
- //println!("read: {}", ast);
- match eval(ast, env) {
- Err(e) => Err(e),
- Ok(exp) => Ok(print(exp)),
- }
- }
- }
+ let ast = try!(read(str.to_string()));
+ //println!("read: {}", ast);
+ let exp = try!(eval(ast, env));
+ Ok(print(exp))
}
fn main() {
@@ -236,6 +189,7 @@ fn main() {
// core.mal: defined using the language itself
let _ = rep("(def! not (fn* (a) (if a false true)))", repl_env.clone());
+ // repl loop
loop {
let line = readline::mal_readline("user> ");
match line { None => break, _ => () }
generated by cgit v1.2.3 (git 2.25.1) at 2025-12-16 03:44:19 +0000