nordic-dev.net/rust
nordic-dev.net/rust
2
0
Fork 0
mirror of https://github.com/rust-lang/rust.git synced 2025-02-08 04:56:58 +00:00
Code Issues Packages Projects Releases Wiki Activity

rustc: Perform explicit type substitution as requested by the programmer

Browse Source
This commit is contained in:
Patrick Walton 2011-02-22 18:31:54 -08:00
parent 3a7271a026
commit b6f1c832e3
1 changed files with 66 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

66
src/comp/middle/typeck.rs
View File

@ -25,6 +25,7 @@ import middle.ty.type_is_scalar;
import std._str;
import std._uint;
import std._vec;
import std.map;
import std.map.hashmap;
import std.option;
import std.option.none;
@ -78,6 +79,65 @@ fn generalize_ty(@crate_ctxt cx, @ty.t t) -> @ty.t {
ret ty.fold_ty(generalizer, t);
}
// Substitutes the user's explicit types for the parameters in a path
// expression.
fn substitute_ty_params(&@crate_ctxt ccx,
@ty.t typ,
vec[@ast.ty] supplied,
&span sp) -> @ty.t {
state obj ty_substituter(@crate_ctxt ccx,
@mutable uint i,
vec[@ast.ty] supplied,
@hashmap[int,@ty.t] substs) {
fn fold_simple_ty(@ty.t typ) -> @ty.t {
alt (typ.struct) {
case (ty.ty_var(?vid)) {
alt (substs.find(vid)) {
case (some[@ty.t](?resolved_ty)) {
ret resolved_ty;
}
case (none[@ty.t]) {
if (i >= _vec.len[@ast.ty](supplied)) {
// Just leave it as an unresolved parameter
// for now. (We will error out later.)
ret typ;
}
auto result = ast_ty_to_ty_crate(ccx,
supplied.(*i));
*i += 1u;
substs.insert(vid, result);
ret result;
}
}
}
case (_) { ret typ; }
}
}
}
fn hash_int(&int x) -> uint { ret x as uint; }
fn eq_int(&int a, &int b) -> bool { ret a == b; }
auto hasher = hash_int;
auto eqer = eq_int;
auto substs = @map.mk_hashmap[int,@ty.t](hasher, eqer);
auto subst_count = @mutable 0u;
auto substituter = ty_substituter(ccx, subst_count, supplied, substs);
auto result = ty.fold_ty(substituter, typ);
auto supplied_len = _vec.len[@ast.ty](supplied);
if ((*subst_count) != supplied_len) {
ccx.sess.span_err(sp, "expected " + _uint.to_str(*subst_count, 10u) +
" type parameter(s) but found " +
_uint.to_str(supplied_len, 10u) + " parameter(s)");
fail;
}
ret result;
}
// 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.
@ -1445,6 +1505,12 @@ fn check_expr(&@fn_ctxt fcx, @ast.expr expr) -> @ast.expr {
}
}
// Substitute type parameters if the user provided some.
if (_vec.len[@ast.ty](pth.node.types) > 0u) {
t = substitute_ty_params(fcx.ccx, t, pth.node.types,
expr.span);
}
ret @fold.respan[ast.expr_](expr.span,
ast.expr_path(pth, defopt,
ast.ann_type(t)));