mikros/rust
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

rustc: Infer the types of type-parametric functions

Browse Source
This commit is contained in:
Patrick Walton 2010-12-16 11:11:48 -08:00
parent 9759d1e08a
commit e6908a66ec
1 changed files with 76 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

76
src/comp/middle/typeck.rs
View File

@ -259,6 +259,79 @@ fn ty_to_str(&@ty typ) -> str {
ret s;
}
// Replaces parameter types inside a type with type variables.
fn generalize_ty(@crate_ctxt cx, @ty t) -> @ty {
fn rewrap(@ty orig, &sty new) -> @ty {
ret @rec(struct=new, mut=orig.mut, cname=orig.cname);
}
fn recur(@crate_ctxt cx, @ty t,
&hashmap[ast.def_id,@ty] ty_params_to_ty_vars) -> @ty {
alt (t.struct) {
case (ty_box(?subty)) {
auto new_subty = recur(cx, subty, ty_params_to_ty_vars);
ret rewrap(t, ty_box(new_subty));
}
case (ty_vec(?subty)) {
auto new_subty = recur(cx, subty, ty_params_to_ty_vars);
ret rewrap(t, ty_vec(new_subty));
}
case (ty_tup(?subtys)) {
let vec[@ty] new_subtys = vec();
for (@ty subty in subtys) {
new_subtys += vec(recur(cx, subty, ty_params_to_ty_vars));
}
ret rewrap(t, ty_tup(new_subtys));
}
case (ty_rec(?fields)) {
let vec[field] new_fields = vec();
for (field fld in fields) {
auto new_ty = recur(cx, fld.ty, ty_params_to_ty_vars);
new_fields += vec(rec(ident=fld.ident, ty=new_ty));
}
ret rewrap(t, ty_rec(new_fields));
}
case (ty_fn(?args, ?ret_ty)) {
let vec[arg] new_args = vec();
for (arg a in args) {
auto new_ty = recur(cx, a.ty, ty_params_to_ty_vars);
new_args += vec(rec(mode=a.mode, ty=new_ty));
}
auto new_ret_ty = recur(cx, ret_ty, ty_params_to_ty_vars);
ret rewrap(t, ty_fn(new_args, new_ret_ty));
}
case (ty_obj(?methods)) {
let vec[method] new_methods = vec();
for (method m in methods) {
let vec[arg] new_args = vec();
for (arg a in m.inputs) {
auto new_ty = recur(cx, a.ty, ty_params_to_ty_vars);
new_args += vec(rec(mode=a.mode, ty=new_ty));
}
auto new_rty = recur(cx, m.output, ty_params_to_ty_vars);
new_methods += vec(rec(ident=m.ident, inputs=new_args,
output=new_rty));
}
ret rewrap(t, ty_obj(new_methods));
}
case (ty_param(?pid)) {
if (ty_params_to_ty_vars.contains_key(pid)) {
ret ty_params_to_ty_vars.get(pid);
}
auto var_ty = next_ty_var(cx);
ty_params_to_ty_vars.insert(pid, var_ty);
ret var_ty;
}
case (_) { /* fall through */ }
}
ret t;
}
auto ty_params_to_ty_vars = common.new_def_hash[@ty]();
ret recur(cx, t, ty_params_to_ty_vars);
}
// Parses the programmer's textual representation of a type into our internal
// notion of a type. `getter` is a function that returns the type
// corresponding to a definition ID.
@ -1720,6 +1793,9 @@ fn check_expr(&fn_ctxt fcx, @ast.expr expr) -> @ast.expr {
fail;
}
}
t = generalize_ty(fcx.ccx, t);
ret @fold.respan[ast.expr_](expr.span,
ast.expr_name(name, defopt,
ast.ann_type(t)));