rust/src/librustc/front/std_inject.rs
2013-07-17 14:57:51 -07:00

128 lines
4.1 KiB
Rust

// Copyright 2012 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.
use driver::session::Session;
use std::vec;
use syntax::ast;
use syntax::attr;
use syntax::codemap::dummy_sp;
use syntax::codemap;
use syntax::fold;
static STD_VERSION: &'static str = "0.8-pre";
pub fn maybe_inject_libstd_ref(sess: Session, crate: @ast::crate)
-> @ast::crate {
if use_std(crate) {
inject_libstd_ref(sess, crate)
} else {
crate
}
}
fn use_std(crate: &ast::crate) -> bool {
!attr::attrs_contains_name(crate.node.attrs, "no_std")
}
fn no_prelude(attrs: &[ast::attribute]) -> bool {
attr::attrs_contains_name(attrs, "no_implicit_prelude")
}
fn inject_libstd_ref(sess: Session, crate: &ast::crate) -> @ast::crate {
fn spanned<T:Copy>(x: T) -> codemap::spanned<T> {
codemap::spanned { node: x, span: dummy_sp() }
}
let precursor = @fold::AstFoldFns {
fold_crate: |crate, span, fld| {
let n1 = sess.next_node_id();
let vi1 = ast::view_item {
node: ast::view_item_extern_mod(
sess.ident_of("std"), ~[], n1),
attrs: ~[
spanned(ast::attribute_ {
style: ast::attr_inner,
value: @spanned(ast::meta_name_value(
@"vers",
spanned(ast::lit_str(STD_VERSION.to_managed()))
)),
is_sugared_doc: false
})
],
vis: ast::private,
span: dummy_sp()
};
let vis = vec::append(~[vi1], crate.module.view_items);
let mut new_module = ast::_mod {
view_items: vis,
..crate.module.clone()
};
if !no_prelude(crate.attrs) {
// only add `use std::prelude::*;` if there wasn't a
// `#[no_implicit_prelude];` at the crate level.
new_module = fld.fold_mod(&new_module);
}
// FIXME #2543: Bad copy.
let new_crate = ast::crate_ {
module: new_module,
..(*crate).clone()
};
(new_crate, span)
},
fold_item: |item, fld| {
if !no_prelude(item.attrs) {
// only recur if there wasn't `#[no_implicit_prelude];`
// on this item, i.e. this means that the prelude is not
// implicitly imported though the whole subtree
fold::noop_fold_item(item, fld)
} else {
Some(item)
}
},
fold_mod: |module, fld| {
let n2 = sess.next_node_id();
let prelude_path = ast::Path {
span: dummy_sp(),
global: false,
idents: ~[
sess.ident_of("std"),
sess.ident_of("prelude")
],
rp: None,
types: ~[]
};
let vp = @spanned(ast::view_path_glob(prelude_path, n2));
let vi2 = ast::view_item { node: ast::view_item_use(~[vp]),
attrs: ~[],
vis: ast::private,
span: dummy_sp() };
let vis = vec::append(~[vi2], module.view_items);
// FIXME #2543: Bad copy.
let new_module = ast::_mod {
view_items: vis,
..(*module).clone()
};
fold::noop_fold_mod(&new_module, fld)
},
..*fold::default_ast_fold()
};
let fold = fold::make_fold(precursor);
@fold.fold_crate(crate)
}