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// 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::ast_fold;
use syntax::fold;
use syntax::opt_vec;
static STD_VERSION: &'static str = "0.8";
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::contains_name(crate.attrs, "no_std")
}
fn no_prelude(attrs: &[ast::Attribute]) -> bool {
attr::contains_name(attrs, "no_implicit_prelude")
}
fn spanned<T>(x: T) -> codemap::Spanned<T> {
codemap::Spanned {
node: x,
span: dummy_sp(),
}
}
struct StandardLibraryInjector {
sess: Session,
}
impl fold::ast_fold for StandardLibraryInjector {
fn fold_crate(&self, crate: &ast::Crate) -> ast::Crate {
let version = STD_VERSION.to_managed();
let vi1 = ast::view_item {
node: ast::view_item_extern_mod(self.sess.ident_of("std"),
None,
~[],
ast::DUMMY_NODE_ID),
attrs: ~[
attr::mk_attr(attr::mk_name_value_item_str(@"vers", version))
],
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 = self.fold_mod(&new_module);
}
// FIXME #2543: Bad copy.
ast::Crate {
module: new_module,
..(*crate).clone()
}
}
fn fold_item(&self, item: @ast::item) -> Option<@ast::item> {
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, self)
} else {
Some(item)
}
}
fn fold_mod(&self, module: &ast::_mod) -> ast::_mod {
let prelude_path = ast::Path {
span: dummy_sp(),
global: false,
segments: ~[
ast::PathSegment {
identifier: self.sess.ident_of("std"),
lifetime: None,
types: opt_vec::Empty,
},
ast::PathSegment {
identifier: self.sess.ident_of("prelude"),
lifetime: None,
types: opt_vec::Empty,
},
],
};
let vp = @spanned(ast::view_path_glob(prelude_path,
ast::DUMMY_NODE_ID));
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, self)
}
}
fn inject_libstd_ref(sess: Session, crate: &ast::Crate) -> @ast::Crate {
let fold = StandardLibraryInjector {
sess: sess,
};
@fold.fold_crate(crate)
}
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