compast_ty.rs

import std._vec;
import std._str;
import std.option;
import middle.ty;
import front.ast;
import util.common;

// Compact string representation for ty.t values. API ty_str & parse_from_str.
// (The second has to be authed pure.) Extra parameters are for converting
// to/from def_ids in the string rep. Whatever format you choose should not
// contain pipe characters.

// Callback to translate defs to strs or back.
type def_str = fn(ast.def_id) -> str;
type str_def = fn(str) -> ast.def_id;

fn ty_str(@ty.t t, def_str ds) -> str {
    auto base = sty_str(t.struct, ds);
    alt (t.mut) {
        case (ast.mut) {ret "m" + base;}
        case (ast.imm) {ret base;}
    }
}

fn sty_str(ty.sty st, def_str ds) -> str {
    alt (st) {
        case (ty.ty_nil) {ret "n";}
        case (ty.ty_bool) {ret "b";}
        case (ty.ty_int) {ret "i";}
        case (ty.ty_uint) {ret "u";}
        case (ty.ty_machine(?mach)) {
            alt (mach) {
                case (common.ty_u8) {ret "Mb";}
                case (common.ty_u16) {ret "Mw";}
                case (common.ty_u32) {ret "Ml";}
                case (common.ty_u64) {ret "Md";}
                case (common.ty_i8) {ret "MB";}
                case (common.ty_i16) {ret "MW";}
                case (common.ty_i32) {ret "ML";}
                case (common.ty_i64) {ret "MD";}
                case (common.ty_f32) {ret "Mf";}
                case (common.ty_f64) {ret "MF";}
            }
        }
        case (ty.ty_char) {ret "c";}
        case (ty.ty_str) {ret "s";}
        case (ty.ty_tag(?def,?tys)) { // TODO restore def_id
            auto acc = "t[" + ds(def) + "|";
            for (@ty.t t in tys) {acc += ty_str(t, ds);}
            ret acc + "]";
        }
        case (ty.ty_box(?t)) {ret "@" + ty_str(t, ds);}
        case (ty.ty_vec(?t)) {ret "V" + ty_str(t, ds);}
        case (ty.ty_port(?t)) {ret "P" + ty_str(t, ds);}
        case (ty.ty_chan(?t)) {ret "C" + ty_str(t, ds);}
        case (ty.ty_tup(?tys)) {
            auto acc = "T[";
            for (@ty.t t in tys) {acc += ty_str(t, ds);}
            ret acc + "]";
        }
        case (ty.ty_rec(?fields)) {
            auto acc = "R[";
            for (ty.field field in fields) {
                acc += field.ident + "=";
                acc += ty_str(field.ty, ds);
            }
            ret acc + "]";
        }
        case (ty.ty_fn(?proto,?args,?out)) {
            ret proto_str(proto) + ty_fn_str(args, out, ds);
        }
        case (ty.ty_native_fn(?abi,?args,?out)) {
            auto abistr;
            alt (abi) {
                case (ast.native_abi_rust) {abistr = "r";}
                case (ast.native_abi_cdecl) {abistr = "c";}
            }
            ret "N" + abistr + ty_fn_str(args, out, ds);
        }
        case (ty.ty_obj(?methods)) {
            auto acc = "O[";
            for (ty.method m in methods) {
                acc += proto_str(m.proto);
                acc += m.ident;
                acc += ty_fn_str(m.inputs, m.output, ds);
            }
            ret acc + "]";
        }
        case (ty.ty_var(?id)) {ret "X" + common.istr(id);}
        case (ty.ty_native) {ret "E";}
        // TODO (maybe?)   ty_param(ast.def_id), ty_type;
    }
}

fn proto_str(ast.proto proto) -> str {
    alt (proto) {
        case (ast.proto_iter) {ret "W";}
        case (ast.proto_fn) {ret "F";}
    }
}

fn ty_fn_str(vec[ty.arg] args, @ty.t out, def_str ds) -> str {
    auto acc = "[";
    for (ty.arg arg in args) {
        if (arg.mode == ast.alias) {acc += "&";}
        acc += ty_str(arg.ty, ds);
    }
    ret acc + "]" + ty_str(out, ds);
}

type pstate = rec(str rep, mutable uint pos, uint len);

fn peek(@pstate st) -> char {
    if (st.pos < st.len) {ret st.rep.(st.pos) as char;}
    else {ret ' ';}
}
impure fn next(@pstate st) -> char { // ?? somehow not recognized as impure
    if (st.pos >= st.len) {fail;}
    auto ch = st.rep.(st.pos);
    st.pos = st.pos + 1u;
    ret ch as char;
}

fn parse_ty_str(str rep, str_def sd) -> @ty.t {
    auto len = _str.byte_len(rep);
    auto st = @rec(rep=rep, mutable pos=0u, len=len);
    auto result = parse_ty(st, sd);
    check(st.pos == len);
    ret result;
}

impure fn parse_ty(@pstate st, str_def sd) -> @ty.t {
    auto mut = ast.imm;
    if (peek(st) == 'm') {
        mut = ast.mut;
        st.pos = st.pos + 1u;
    }
    ret @rec(struct=parse_sty(st, sd),
             mut=mut,
             cname=option.none[str]);
}

impure fn parse_sty(@pstate st, str_def sd) -> ty.sty {
    alt (next(st)) {
        case ('n') {ret ty.ty_nil;}
        case ('b') {ret ty.ty_bool;}
        case ('i') {ret ty.ty_int;}
        case ('u') {ret ty.ty_uint;}
        case ('M') {
            alt (next(st)) {
                case ('b') {ret ty.ty_machine(common.ty_u8);}
                case ('w') {ret ty.ty_machine(common.ty_u16);}
                case ('l') {ret ty.ty_machine(common.ty_u32);}
                case ('d') {ret ty.ty_machine(common.ty_u64);}
                case ('B') {ret ty.ty_machine(common.ty_i8);}
                case ('W') {ret ty.ty_machine(common.ty_i16);}
                case ('L') {ret ty.ty_machine(common.ty_i32);}
                case ('D') {ret ty.ty_machine(common.ty_i64);}
                case ('f') {ret ty.ty_machine(common.ty_f32);}
                case ('F') {ret ty.ty_machine(common.ty_f64);}
            }
        }
        case ('c') {ret ty.ty_char;}
        case ('s') {ret ty.ty_str;}
        case ('t') {
            check(next(st) == '[');
            auto def = "";
            while (peek(st) != '|') {def += _str.from_char(next(st));}
            st.pos = st.pos + 1u;
            let vec[@ty.t] params = vec();
            while (peek(st) != ']') {
                params = _vec.push[@ty.t](params, parse_ty(st, sd));
            }
            st.pos = st.pos + 1u;
            ret ty.ty_tag(sd(def), params);
        }      
        case ('@') {ret ty.ty_box(parse_ty(st, sd));}
        case ('V') {ret ty.ty_vec(parse_ty(st, sd));}
        case ('P') {ret ty.ty_port(parse_ty(st, sd));}
        case ('C') {ret ty.ty_chan(parse_ty(st, sd));}
        case ('T') {
            check(next(st) == '[');
            let vec[@ty.t] params = vec();
            while (peek(st) != ']') {
                params = _vec.push[@ty.t](params, parse_ty(st, sd));
            }
            st.pos = st.pos + 1u;
            ret ty.ty_tup(params);
        }
        case ('R') {
            check(next(st) == '[');
            let vec[ty.field] fields = vec();
            while (peek(st) != ']') {
                auto name = "";
                while (peek(st) != '=') {name += _str.from_char(next(st));}
                st.pos = st.pos + 1u;
                fields = _vec.push[ty.field]
                    (fields, rec(ident=name, ty=parse_ty(st, sd)));
            }
            st.pos = st.pos + 1u;
            ret ty.ty_rec(fields);
        }
        case ('F') {
            auto func = parse_ty_fn(st, sd);
            ret ty.ty_fn(ast.proto_fn, func._0, func._1);
        }
        case ('W') {
            auto func = parse_ty_fn(st, sd);
            ret ty.ty_fn(ast.proto_iter, func._0, func._1);
        }
        case ('N') {
            auto abi;
            alt (next(st)) {
                case ('r') {abi = ast.native_abi_rust;}
                case ('c') {abi = ast.native_abi_cdecl;}
            }
            auto func = parse_ty_fn(st, sd);
            ret ty.ty_native_fn(abi,func._0,func._1);
        }
        case ('O') {
            check(next(st) == '[');
            let vec[ty.method] methods = vec();
            while (peek(st) != ']') {
                auto proto;
                alt (next(st)) {
                    case ('W') {proto = ast.proto_iter;}
                    case ('F') {proto = ast.proto_fn;}
                }
                auto name = "";
                while (peek(st) != '[') {name += _str.from_char(next(st));}
                auto func = parse_ty_fn(st, sd);
                methods = _vec.push[ty.method]
                    (methods, rec(proto=proto,
                                  ident=name,
                                  inputs=func._0,
                                  output=func._1));
            }
            ret ty.ty_obj(methods);
        }
        case ('X') {ret ty.ty_var(parse_int(st));}
        case ('E') {ret ty.ty_native;}
    }
}

impure fn parse_int(@pstate st) -> int {
    auto n = 0;
    while (true) {
        auto cur = peek(st);
        if (cur < '0' || cur > '9') {break;}
        st.pos = st.pos + 1u;
        n *= 10;
        n += (cur as int) - ('0' as int);
    }
    ret n;
}

impure fn parse_ty_fn(@pstate st, str_def sd) -> tup(vec[ty.arg], @ty.t) {
    check(next(st) == '[');
    let vec[ty.arg] inputs = vec();
    while (peek(st) != ']') {
        auto mode = ast.val;
        if (peek(st) == '&') {
            mode = ast.alias;
            st.pos = st.pos + 1u;
        }
        inputs = _vec.push[ty.arg]
            (inputs, rec(mode=mode, ty=parse_ty(st, sd)));
    }
    st.pos = st.pos + 1u;
    ret tup(inputs, parse_ty(st, sd));
}

// Local Variables:
// mode: rust
// fill-column: 78;
// indent-tabs-mode: nil
// c-basic-offset: 4
// buffer-file-coding-system: utf-8-unix
// compile-command: "make -k -C ../.. 2>&1 | sed -e 's/\\/x\\//x:\\//g'";
// End: