f94d671bfa
This commit revisits the `cast` module in libcore and libstd, and scrutinizes
all functions inside of it. The result was to remove the `cast` module entirely,
folding all functionality into the `mem` module. Specifically, this is the fate
of each function in the `cast` module.
* transmute - This function was moved to `mem`, but it is now marked as
#[unstable]. This is due to planned changes to the `transmute`
function and how it can be invoked (see the #[unstable] comment).
For more information, see RFC 5 and #12898
* transmute_copy - This function was moved to `mem`, with clarification that is
is not an error to invoke it with T/U that are different
sizes, but rather that it is strongly discouraged. This
function is now #[stable]
* forget - This function was moved to `mem` and marked #[stable]
* bump_box_refcount - This function was removed due to the deprecation of
managed boxes as well as its questionable utility.
* transmute_mut - This function was previously deprecated, and removed as part
of this commit.
* transmute_mut_unsafe - This function doesn't serve much of a purpose when it
can be achieved with an `as` in safe code, so it was
removed.
* transmute_lifetime - This function was removed because it is likely a strong
indication that code is incorrect in the first place.
* transmute_mut_lifetime - This function was removed for the same reasons as
`transmute_lifetime`
* copy_lifetime - This function was moved to `mem`, but it is marked
`#[unstable]` now due to the likelihood of being removed in
the future if it is found to not be very useful.
* copy_mut_lifetime - This function was also moved to `mem`, but had the same
treatment as `copy_lifetime`.
* copy_lifetime_vec - This function was removed because it is not used today,
and its existence is not necessary with DST
(copy_lifetime will suffice).
In summary, the cast module was stripped down to these functions, and then the
functions were moved to the `mem` module.
transmute - #[unstable]
transmute_copy - #[stable]
forget - #[stable]
copy_lifetime - #[unstable]
copy_mut_lifetime - #[unstable]
[breaking-change]
132 lines
3.4 KiB
Rust
132 lines
3.4 KiB
Rust
// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
|
|
// file at the top-level directory of this distribution and at
|
|
// http://rust-lang.org/COPYRIGHT.
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
|
|
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
|
|
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
|
|
// option. This file may not be copied, modified, or distributed
|
|
// except according to those terms.
|
|
|
|
|
|
// Test a sample usage pattern for regions. Makes use of the
|
|
// following features:
|
|
//
|
|
// - Multiple lifetime parameters
|
|
// - Arenas
|
|
|
|
extern crate arena;
|
|
extern crate collections;
|
|
extern crate libc;
|
|
|
|
use arena::Arena;
|
|
use collections::HashMap;
|
|
use std::mem;
|
|
|
|
type Type<'tcx> = &'tcx TypeStructure<'tcx>;
|
|
|
|
#[deriving(Show)]
|
|
enum TypeStructure<'tcx> {
|
|
TypeInt,
|
|
TypeFunction(Type<'tcx>, Type<'tcx>),
|
|
}
|
|
impl<'tcx> Eq for TypeStructure<'tcx> {
|
|
fn eq(&self, other: &TypeStructure<'tcx>) -> bool {
|
|
match (*self, *other) {
|
|
(TypeInt, TypeInt) => true,
|
|
(TypeFunction(s_a, s_b), TypeFunction(o_a, o_b)) => *s_a == *o_a && *s_b == *o_b,
|
|
_ => false
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<'tcx> TotalEq for TypeStructure<'tcx> {}
|
|
|
|
struct TypeContext<'tcx, 'ast> {
|
|
ty_arena: &'tcx Arena,
|
|
types: Vec<Type<'tcx>> ,
|
|
type_table: HashMap<NodeId, Type<'tcx>>,
|
|
|
|
ast_arena: &'ast Arena,
|
|
ast_counter: uint,
|
|
}
|
|
|
|
impl<'tcx,'ast> TypeContext<'tcx, 'ast> {
|
|
fn new(ty_arena: &'tcx Arena, ast_arena: &'ast Arena)
|
|
-> TypeContext<'tcx, 'ast> {
|
|
TypeContext { ty_arena: ty_arena,
|
|
types: Vec::new(),
|
|
type_table: HashMap::new(),
|
|
|
|
ast_arena: ast_arena,
|
|
ast_counter: 0 }
|
|
}
|
|
|
|
fn add_type(&mut self, s: TypeStructure<'tcx>) -> Type<'tcx> {
|
|
for &ty in self.types.iter() {
|
|
if *ty == s {
|
|
return ty;
|
|
}
|
|
}
|
|
|
|
let ty = self.ty_arena.alloc(|| s);
|
|
self.types.push(ty);
|
|
ty
|
|
}
|
|
|
|
fn set_type(&mut self, id: NodeId, ty: Type<'tcx>) -> Type<'tcx> {
|
|
self.type_table.insert(id, ty);
|
|
ty
|
|
}
|
|
|
|
fn ast(&mut self, a: AstKind<'ast>) -> Ast<'ast> {
|
|
let id = self.ast_counter;
|
|
self.ast_counter += 1;
|
|
self.ast_arena.alloc(|| AstStructure { id: NodeId {id:id}, kind: a })
|
|
}
|
|
}
|
|
|
|
#[deriving(Eq, TotalEq, Hash)]
|
|
struct NodeId {
|
|
id: uint
|
|
}
|
|
|
|
type Ast<'ast> = &'ast AstStructure<'ast>;
|
|
|
|
struct AstStructure<'ast> {
|
|
id: NodeId,
|
|
kind: AstKind<'ast>
|
|
}
|
|
|
|
enum AstKind<'ast> {
|
|
ExprInt,
|
|
ExprVar(uint),
|
|
ExprLambda(Ast<'ast>),
|
|
}
|
|
|
|
fn compute_types<'tcx,'ast>(tcx: &mut TypeContext<'tcx,'ast>,
|
|
ast: Ast<'ast>) -> Type<'tcx>
|
|
{
|
|
match ast.kind {
|
|
ExprInt | ExprVar(_) => {
|
|
let ty = tcx.add_type(TypeInt);
|
|
tcx.set_type(ast.id, ty)
|
|
}
|
|
ExprLambda(ast) => {
|
|
let arg_ty = tcx.add_type(TypeInt);
|
|
let body_ty = compute_types(tcx, ast);
|
|
let lambda_ty = tcx.add_type(TypeFunction(arg_ty, body_ty));
|
|
tcx.set_type(ast.id, lambda_ty)
|
|
}
|
|
}
|
|
}
|
|
|
|
pub fn main() {
|
|
let ty_arena = arena::Arena::new();
|
|
let ast_arena = arena::Arena::new();
|
|
let mut tcx = TypeContext::new(&ty_arena, &ast_arena);
|
|
let ast = tcx.ast(ExprInt);
|
|
let ty = compute_types(&mut tcx, ast);
|
|
assert_eq!(*ty, TypeInt);
|
|
}
|