1 // Copyright 2012 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
13 use codemap::{DUMMY_SP, Span, ExpnInfo, NameAndSpan, MacroAttribute};
17 use parse::token::InternedString;
18 use parse::token::special_idents;
19 use parse::{token, ParseSess};
21 use util::small_vector::SmallVector;
23 /// Craft a span that will be ignored by the stability lint's
24 /// call to codemap's is_internal check.
25 /// The expanded code uses the unstable `#[prelude_import]` attribute.
26 fn ignored_span(sess: &ParseSess, sp: Span) -> Span {
30 name: "std_inject".to_string(),
31 format: MacroAttribute,
33 allow_internal_unstable: true,
36 let expn_id = sess.codemap().record_expansion(info);
42 pub fn maybe_inject_crates_ref(krate: ast::Crate, alt_std_name: Option<String>)
45 inject_crates_ref(krate, alt_std_name)
51 pub fn maybe_inject_prelude(sess: &ParseSess, krate: ast::Crate) -> ast::Crate {
53 let mut fold = PreludeInjector {
54 span: ignored_span(sess, DUMMY_SP)
56 fold.fold_crate(krate)
62 pub fn use_std(krate: &ast::Crate) -> bool {
63 !attr::contains_name(&krate.attrs, "no_std")
66 fn no_prelude(attrs: &[ast::Attribute]) -> bool {
67 attr::contains_name(attrs, "no_implicit_prelude")
70 struct StandardLibraryInjector {
71 alt_std_name: Option<String>,
74 impl fold::Folder for StandardLibraryInjector {
75 fn fold_crate(&mut self, mut krate: ast::Crate) -> ast::Crate {
77 // The name to use in `extern crate name as std;`
78 let actual_crate_name = match self.alt_std_name {
79 Some(ref s) => token::intern(&s),
80 None => token::intern("std"),
83 krate.module.items.insert(0, P(ast::Item {
84 id: ast::DUMMY_NODE_ID,
85 ident: token::str_to_ident("std"),
87 attr::mk_attr_outer(attr::mk_attr_id(), attr::mk_word_item(
88 InternedString::new("macro_use")))),
89 node: ast::ItemExternCrate(Some(actual_crate_name)),
98 fn inject_crates_ref(krate: ast::Crate, alt_std_name: Option<String>) -> ast::Crate {
99 let mut fold = StandardLibraryInjector {
100 alt_std_name: alt_std_name
102 fold.fold_crate(krate)
105 struct PreludeInjector {
109 impl fold::Folder for PreludeInjector {
110 fn fold_crate(&mut self, mut krate: ast::Crate) -> ast::Crate {
111 // only add `use std::prelude::*;` if there wasn't a
112 // `#![no_implicit_prelude]` at the crate level.
113 // fold_mod() will insert glob path.
114 if !no_prelude(&krate.attrs) {
115 krate.module = self.fold_mod(krate.module);
120 fn fold_item(&mut self, item: P<ast::Item>) -> SmallVector<P<ast::Item>> {
121 if !no_prelude(&item.attrs) {
122 // only recur if there wasn't `#![no_implicit_prelude]`
123 // on this item, i.e. this means that the prelude is not
124 // implicitly imported though the whole subtree
125 fold::noop_fold_item(item, self)
127 SmallVector::one(item)
131 fn fold_mod(&mut self, mut mod_: ast::Mod) -> ast::Mod {
132 let prelude_path = ast::Path {
137 identifier: token::str_to_ident("std"),
138 parameters: ast::PathParameters::none(),
141 identifier: token::str_to_ident("prelude"),
142 parameters: ast::PathParameters::none(),
145 identifier: token::str_to_ident("v1"),
146 parameters: ast::PathParameters::none(),
151 let vp = P(codemap::dummy_spanned(ast::ViewPathGlob(prelude_path)));
152 mod_.items.insert(0, P(ast::Item {
153 id: ast::DUMMY_NODE_ID,
154 ident: special_idents::invalid,
155 node: ast::ItemUse(vp),
156 attrs: vec![ast::Attribute {
158 node: ast::Attribute_ {
159 id: attr::mk_attr_id(),
160 style: ast::AttrOuter,
161 value: P(ast::MetaItem {
163 node: ast::MetaWord(special_idents::prelude_import.name.as_str()),
165 is_sugared_doc: false,
172 fold::noop_fold_mod(mod_, self)