1 files changed, 381 insertions, 0 deletions
diff --git a/rust/src/bin/stepA_mal.rs b/rust/src/bin/stepA_mal.rs
new file mode 100644
index 0000000..b84a079
--- /dev/null
+++ b/rust/src/bin/stepA_mal.rs
@@ -0,0 +1,381 @@
+#![feature(exit_status)]
+
+extern crate mal;
+
+use std::collections::HashMap;
+use std::env as stdenv;
+
+use mal::types::{MalVal, MalRet, MalError, err_str};
+use mal::types::{symbol, _nil, string, list, vector, hash_map, malfunc, malfuncd};
+use mal::types::MalType::{Nil, False, Sym, List, Vector, Hash_Map, Func, MalFunc};
+use mal::types::MalError::{ErrString, ErrMalVal};
+use mal::{readline, reader, core};
+use mal::env::{env_set, env_get, env_new, env_bind, env_find, env_root, Env};
+
+// read
+fn read(str: String) -> MalRet {
+    reader::read_str(str)
+}
+
+// eval
+fn is_pair(x: MalVal) -> bool {
+    match *x {
+        List(ref lst,_) | Vector(ref lst,_) => lst.len() > 0,
+        _ => false,
+    }
+}
+
+fn quasiquote(ast: MalVal) -> MalVal {
+    if !is_pair(ast.clone()) {
+        return list(vec![symbol("quote"), ast])
+    }
+
+    match *ast.clone() {
+        List(ref args,_) | Vector(ref args,_) => {
+            let ref a0 = args[0];
+            match **a0 {
+                Sym(ref s) if *s == "unquote" => return args[1].clone(),
+                _ => (),
+            }
+            if is_pair(a0.clone()) {
+                match **a0 {
+                    List(ref a0args,_) | Vector(ref a0args,_) => {
+                        match *a0args[0] {
+                            Sym(ref s) if *s == "splice-unquote" => {
+                                return list(vec![symbol("concat"),
+                                                 a0args[1].clone(),
+                                                 quasiquote(list(args[1..].to_vec()))])
+                            },
+                            _ => (),
+                        }
+                    },
+                    _ => (),
+                }
+            }
+            let rest = list(args[1..].to_vec());
+            return list(vec![symbol("cons"),
+                             quasiquote(a0.clone()),
+                             quasiquote(rest)])
+        },
+        _ => _nil(), // should never reach
+    }
+}
+
+fn is_macro_call(ast: MalVal, env: Env) -> bool {
+    let lst = match *ast {
+        List(ref lst,_) => &lst[0],
+        _ => return false
+    };
+    match **lst {
+        Sym(_) => {},
+        _ => return false
+    }
+    if env_find(&env, lst).is_none() {
+        return false
+    }
+    let f = match env_get(&env, lst) {
+        Ok(f) => f,
+        _ => return false
+    };
+    match *f {
+        MalFunc(ref mfd,_) => mfd.is_macro,
+        _ => false,
+    }
+}
+
+fn macroexpand(mut ast: MalVal, env: Env) -> MalRet {
+    while is_macro_call(ast.clone(), env.clone()) {
+        let ast2 = ast.clone();
+        let args = match *ast2 {
+            List(ref args,_) => args,
+            _ => break,
+        };
+        let ref a0 = args[0];
+        let mf = match **a0 {
+            Sym(_) => try!(env_get(&env, &a0)),
+            _ => break,
+        };
+        match *mf {
+            MalFunc(_,_) => ast = try!(mf.apply(args[1..].to_vec())),
+            _ => break,
+        }
+    }
+    Ok(ast)
+}
+
+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(mut ast: MalVal, mut env: Env) -> MalRet {
+    'tco: loop {
+
+    //println!("eval: {}, {}", ast, env.borrow());
+    //println!("eval: {}", ast);
+    match *ast {
+        List(_,_) => (),  // continue
+        _ => return eval_ast(ast, env),
+    }
+
+    // apply list
+    ast = try!(macroexpand(ast, env.clone()));
+    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"),
+            }
+            ast = a2;
+            env = let_env.clone();
+            continue 'tco;
+        },
+        "quote" => return Ok((*args)[1].clone()),
+        "quasiquote" => {
+            let a1 = (*args)[1].clone();
+            ast = quasiquote(a1);
+            continue 'tco;
+        },
+        "defmacro!" => {
+            let a1 = (*args)[1].clone();
+            let a2 = (*args)[2].clone();
+            let r = try!(eval(a2, env.clone()));
+            match *r {
+                MalFunc(ref mfd,_) => {
+                    match *a1 {
+                        Sym(_) => {
+                            let mut new_mfd = mfd.clone();
+                            new_mfd.is_macro = true;
+                            let mf = malfuncd(new_mfd,_nil());
+                            env_set(&env.clone(), a1.clone(), mf.clone());
+                            return Ok(mf);
+                        },
+                        _ => return err_str("def! of non-symbol"),
+                    }
+                },
+                _ => return err_str("def! of non-symbol"),
+            }
+        },
+        "macroexpand" => {
+            let a1 = (*args)[1].clone();
+            return macroexpand(a1, env.clone())
+        },
+        "try*" => {
+            let a1 = (*args)[1].clone();
+            match eval(a1, env.clone()) {
+                Ok(res) => return Ok(res),
+                Err(err) => {
+                    if args.len() < 3 { return Err(err); }
+                    let a2 = (*args)[2].clone();
+                    let cat = match *a2 {
+                        List(ref cat,_) => cat,
+                        _ => return err_str("invalid catch* clause"),
+                    };
+                    if cat.len() != 3 {
+                        return err_str("wrong arity to catch* clause");
+                    }
+                    let c1 = (*cat)[1].clone();
+                    match *c1 {
+                        Sym(_) => {},
+                        _ => return err_str("invalid catch* binding"),
+                    };
+                    let exc = match err {
+                        ErrMalVal(mv) => mv,
+                        ErrString(s) => string(s),
+                    };
+                    let bind_env = env_new(Some(env.clone()));
+                    env_set(&bind_env, c1.clone(), exc);
+                    let c2 = (*cat)[2].clone();
+                    return eval(c2, bind_env);
+                },
+            };
+        }
+        "do" => {
+            let el = list(args[1..args.len()-1].to_vec());
+            try!(eval_ast(el, env.clone()));
+            ast = args[args.len() - 1].clone();
+            continue 'tco;
+        },
+        "if" => {
+            let a1 = (*args)[1].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, a1, _nil()));
+        },
+        "eval" => {
+            let a1 = (*args)[1].clone();
+            ast = try!(eval(a1, env.clone()));
+            env = env_root(&env);
+            continue 'tco;
+        },
+        _ => { // function call
+            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(e) => err_str(&e),
+                    }
+                },
+                _ => err_str("attempt to call non-function"),
+            }
+        },
+    }
+
+    }
+}
+
+// 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 main() {
+    // core.rs: defined using rust
+    let repl_env = env_new(None);
+    for (k, v) in core::ns().into_iter() {
+        env_set(&repl_env, symbol(&k), v);
+    }
+    // see eval() for definition of "eval"
+    env_set(&repl_env, symbol("*ARGV*"), list(vec![]));
+
+    // core.mal: defined using the language itself
+    let _ = rep("(def! *host-language* \"rust\")", repl_env.clone());
+    let _ = rep("(def! not (fn* (a) (if a false true)))", repl_env.clone());
+    let _ = rep("(def! load-file (fn* (f) (eval (read-string (str \"(do \" (slurp f) \")\")))))", repl_env.clone());
+    let _ = rep("(defmacro! cond (fn* (& xs) (if (> (count xs) 0) (list 'if (first xs) (if (> (count xs) 1) (nth xs 1) (throw \"odd number of forms to cond\")) (cons 'cond (rest (rest xs)))))))", repl_env.clone());
+    let _ = rep("(defmacro! or (fn* (& xs) (if (empty? xs) nil (if (= 1 (count xs)) (first xs) `(let* (or_FIXME ~(first xs)) (if or_FIXME or_FIXME (or ~@(rest xs))))))))", repl_env.clone());
+
+    // Invoked with command line arguments
+    let args = stdenv::args();
+    if args.len() > 1 {
+        let mv_args = args.skip(2)
+            .map(|a| string(a))
+            .collect::<Vec<MalVal>>();
+        env_set(&repl_env, symbol("*ARGV*"), list(mv_args));
+        let lf = format!("(load-file \"{}\")",
+                         stdenv::args().skip(1).next().unwrap());
+        return match rep(&lf, repl_env.clone()) {
+            Ok(_) => stdenv::set_exit_status(0),
+            Err(str) => {
+                println!("Error: {:?}", str);
+                stdenv::set_exit_status(1);
+            }
+        };
+    }
+
+    // repl loop
+    let _  = rep("(println (str \"Mal [\" *host-language* \"]\"))", repl_env.clone());
+    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),
+        }
+    }
+}