0bdfd0f4c7
Closes #11692. Instead of returning the original expression, a dummy expression (with identical span) is returned. This prevents infinite loops of failed expansions as well as odd double error messages in certain situations.
559 lines
19 KiB
Rust
559 lines
19 KiB
Rust
// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use ast;
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use ast::Name;
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use codemap;
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use codemap::{CodeMap, Span, ExpnInfo};
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use ext;
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use ext::expand;
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use parse;
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use parse::token;
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use parse::token::{InternedString, intern, str_to_ident};
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use util::small_vector::SmallVector;
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use std::hashmap::HashMap;
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// new-style macro! tt code:
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//
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// MacResult, NormalTT, IdentTT
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//
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// also note that ast::Mac used to have a bunch of extraneous cases and
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// is now probably a redundant AST node, can be merged with
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// ast::MacInvocTT.
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pub struct MacroDef {
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name: ~str,
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ext: SyntaxExtension
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}
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pub type ItemDecorator =
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fn(&mut ExtCtxt, Span, @ast::MetaItem, @ast::Item, |@ast::Item|);
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pub struct BasicMacroExpander {
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expander: MacroExpanderFn,
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span: Option<Span>
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}
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pub trait MacroExpander {
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fn expand(&self,
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ecx: &mut ExtCtxt,
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span: Span,
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token_tree: &[ast::TokenTree])
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-> MacResult;
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}
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pub type MacroExpanderFn =
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fn(ecx: &mut ExtCtxt, span: codemap::Span, token_tree: &[ast::TokenTree])
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-> MacResult;
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impl MacroExpander for BasicMacroExpander {
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fn expand(&self,
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ecx: &mut ExtCtxt,
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span: Span,
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token_tree: &[ast::TokenTree])
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-> MacResult {
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(self.expander)(ecx, span, token_tree)
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}
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}
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pub struct BasicIdentMacroExpander {
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expander: IdentMacroExpanderFn,
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span: Option<Span>
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}
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pub trait IdentMacroExpander {
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fn expand(&self,
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cx: &mut ExtCtxt,
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sp: Span,
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ident: ast::Ident,
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token_tree: ~[ast::TokenTree])
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-> MacResult;
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}
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impl IdentMacroExpander for BasicIdentMacroExpander {
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fn expand(&self,
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cx: &mut ExtCtxt,
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sp: Span,
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ident: ast::Ident,
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token_tree: ~[ast::TokenTree])
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-> MacResult {
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(self.expander)(cx, sp, ident, token_tree)
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}
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}
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pub type IdentMacroExpanderFn =
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fn(&mut ExtCtxt, Span, ast::Ident, ~[ast::TokenTree]) -> MacResult;
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pub type MacroCrateRegistrationFun =
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fn(|ast::Name, SyntaxExtension|);
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pub trait AnyMacro {
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fn make_expr(&self) -> @ast::Expr;
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fn make_items(&self) -> SmallVector<@ast::Item>;
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fn make_stmt(&self) -> @ast::Stmt;
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}
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pub enum MacResult {
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MRExpr(@ast::Expr),
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MRItem(@ast::Item),
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MRAny(~AnyMacro:),
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MRDef(MacroDef),
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}
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impl MacResult {
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/// Create an empty expression MacResult; useful for satisfying
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/// type signatures after emitting a non-fatal error (which stop
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/// compilation well before the validity (or otherwise)) of the
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/// expression are checked.
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pub fn raw_dummy_expr(sp: codemap::Span) -> @ast::Expr {
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@ast::Expr {
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id: ast::DUMMY_NODE_ID,
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node: ast::ExprLogLevel,
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span: sp
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}
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}
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pub fn dummy_expr(sp: codemap::Span) -> MacResult {
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MRExpr(MacResult::raw_dummy_expr(sp))
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}
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}
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pub enum SyntaxExtension {
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// #[deriving] and such
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ItemDecorator(ItemDecorator),
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// Token-tree expanders
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NormalTT(~MacroExpander:'static, Option<Span>),
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// An IdentTT is a macro that has an
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// identifier in between the name of the
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// macro and the argument. Currently,
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// the only examples of this is
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// macro_rules!
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// perhaps macro_rules! will lose its odd special identifier argument,
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// and this can go away also
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IdentTT(~IdentMacroExpander:'static, Option<Span>),
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}
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pub struct BlockInfo {
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// should macros escape from this scope?
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macros_escape : bool,
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// what are the pending renames?
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pending_renames : RenameList,
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}
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impl BlockInfo {
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pub fn new() -> BlockInfo {
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BlockInfo {
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macros_escape: false,
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pending_renames: ~[],
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}
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}
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}
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// a list of ident->name renamings
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pub type RenameList = ~[(ast::Ident,Name)];
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// The base map of methods for expanding syntax extension
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// AST nodes into full ASTs
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pub fn syntax_expander_table() -> SyntaxEnv {
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// utility function to simplify creating NormalTT syntax extensions
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fn builtin_normal_expander(f: MacroExpanderFn) -> SyntaxExtension {
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NormalTT(~BasicMacroExpander {
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expander: f,
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span: None,
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},
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None)
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}
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let mut syntax_expanders = SyntaxEnv::new();
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syntax_expanders.insert(intern(&"macro_rules"),
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IdentTT(~BasicIdentMacroExpander {
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expander: ext::tt::macro_rules::add_new_extension,
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span: None,
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},
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None));
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syntax_expanders.insert(intern(&"fmt"),
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builtin_normal_expander(
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ext::fmt::expand_syntax_ext));
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syntax_expanders.insert(intern(&"format_args"),
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builtin_normal_expander(
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ext::format::expand_args));
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syntax_expanders.insert(intern(&"env"),
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builtin_normal_expander(
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ext::env::expand_env));
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syntax_expanders.insert(intern(&"option_env"),
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builtin_normal_expander(
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ext::env::expand_option_env));
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syntax_expanders.insert(intern("bytes"),
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builtin_normal_expander(
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ext::bytes::expand_syntax_ext));
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syntax_expanders.insert(intern("concat_idents"),
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builtin_normal_expander(
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ext::concat_idents::expand_syntax_ext));
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syntax_expanders.insert(intern("concat"),
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builtin_normal_expander(
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ext::concat::expand_syntax_ext));
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syntax_expanders.insert(intern(&"log_syntax"),
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builtin_normal_expander(
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ext::log_syntax::expand_syntax_ext));
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syntax_expanders.insert(intern(&"deriving"),
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ItemDecorator(ext::deriving::expand_meta_deriving));
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// Quasi-quoting expanders
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syntax_expanders.insert(intern(&"quote_tokens"),
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builtin_normal_expander(
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ext::quote::expand_quote_tokens));
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syntax_expanders.insert(intern(&"quote_expr"),
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builtin_normal_expander(
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ext::quote::expand_quote_expr));
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syntax_expanders.insert(intern(&"quote_ty"),
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builtin_normal_expander(
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ext::quote::expand_quote_ty));
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syntax_expanders.insert(intern(&"quote_item"),
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builtin_normal_expander(
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ext::quote::expand_quote_item));
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syntax_expanders.insert(intern(&"quote_pat"),
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builtin_normal_expander(
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ext::quote::expand_quote_pat));
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syntax_expanders.insert(intern(&"quote_stmt"),
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builtin_normal_expander(
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ext::quote::expand_quote_stmt));
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syntax_expanders.insert(intern(&"line"),
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builtin_normal_expander(
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ext::source_util::expand_line));
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syntax_expanders.insert(intern(&"col"),
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builtin_normal_expander(
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ext::source_util::expand_col));
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syntax_expanders.insert(intern(&"file"),
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builtin_normal_expander(
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ext::source_util::expand_file));
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syntax_expanders.insert(intern(&"stringify"),
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builtin_normal_expander(
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ext::source_util::expand_stringify));
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syntax_expanders.insert(intern(&"include"),
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builtin_normal_expander(
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ext::source_util::expand_include));
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syntax_expanders.insert(intern(&"include_str"),
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builtin_normal_expander(
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ext::source_util::expand_include_str));
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syntax_expanders.insert(intern(&"include_bin"),
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builtin_normal_expander(
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ext::source_util::expand_include_bin));
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syntax_expanders.insert(intern(&"module_path"),
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builtin_normal_expander(
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ext::source_util::expand_mod));
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syntax_expanders.insert(intern(&"asm"),
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builtin_normal_expander(
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ext::asm::expand_asm));
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syntax_expanders.insert(intern(&"cfg"),
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builtin_normal_expander(
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ext::cfg::expand_cfg));
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syntax_expanders.insert(intern(&"trace_macros"),
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builtin_normal_expander(
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ext::trace_macros::expand_trace_macros));
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syntax_expanders
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}
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pub struct MacroCrate {
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lib: Option<Path>,
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cnum: ast::CrateNum,
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}
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pub trait CrateLoader {
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fn load_crate(&mut self, krate: &ast::ViewItem) -> MacroCrate;
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fn get_exported_macros(&mut self, crate_num: ast::CrateNum) -> ~[~str];
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fn get_registrar_symbol(&mut self, crate_num: ast::CrateNum) -> Option<~str>;
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}
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// One of these is made during expansion and incrementally updated as we go;
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// when a macro expansion occurs, the resulting nodes have the backtrace()
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// -> expn_info of their expansion context stored into their span.
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pub struct ExtCtxt<'a> {
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parse_sess: @parse::ParseSess,
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cfg: ast::CrateConfig,
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backtrace: Option<@ExpnInfo>,
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loader: &'a mut CrateLoader,
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mod_path: ~[ast::Ident],
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trace_mac: bool
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}
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impl<'a> ExtCtxt<'a> {
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pub fn new<'a>(parse_sess: @parse::ParseSess, cfg: ast::CrateConfig,
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loader: &'a mut CrateLoader) -> ExtCtxt<'a> {
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ExtCtxt {
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parse_sess: parse_sess,
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cfg: cfg,
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backtrace: None,
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loader: loader,
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mod_path: ~[],
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trace_mac: false
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}
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}
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pub fn expand_expr(&mut self, mut e: @ast::Expr) -> @ast::Expr {
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loop {
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match e.node {
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ast::ExprMac(..) => {
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let mut expander = expand::MacroExpander {
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extsbox: syntax_expander_table(),
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cx: self,
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};
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e = expand::expand_expr(e, &mut expander);
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}
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_ => return e
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}
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}
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}
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pub fn codemap(&self) -> @CodeMap { self.parse_sess.cm }
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pub fn parse_sess(&self) -> @parse::ParseSess { self.parse_sess }
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pub fn cfg(&self) -> ast::CrateConfig { self.cfg.clone() }
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pub fn call_site(&self) -> Span {
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match self.backtrace {
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Some(expn_info) => expn_info.call_site,
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None => self.bug("missing top span")
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}
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}
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pub fn print_backtrace(&self) { }
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pub fn backtrace(&self) -> Option<@ExpnInfo> { self.backtrace }
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pub fn mod_push(&mut self, i: ast::Ident) { self.mod_path.push(i); }
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pub fn mod_pop(&mut self) { self.mod_path.pop().unwrap(); }
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pub fn mod_path(&self) -> ~[ast::Ident] { self.mod_path.clone() }
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pub fn bt_push(&mut self, ei: codemap::ExpnInfo) {
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match ei {
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ExpnInfo {call_site: cs, callee: ref callee} => {
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self.backtrace =
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Some(@ExpnInfo {
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call_site: Span {lo: cs.lo, hi: cs.hi,
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expn_info: self.backtrace},
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callee: (*callee).clone()
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});
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}
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}
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}
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pub fn bt_pop(&mut self) {
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match self.backtrace {
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Some(expn_info) => self.backtrace = expn_info.call_site.expn_info,
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_ => self.bug("tried to pop without a push")
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}
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}
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/// Emit `msg` attached to `sp`, and stop compilation immediately.
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///
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/// `span_err` should be strongly prefered where-ever possible:
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/// this should *only* be used when
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/// - continuing has a high risk of flow-on errors (e.g. errors in
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/// declaring a macro would cause all uses of that macro to
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/// complain about "undefined macro"), or
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/// - there is literally nothing else that can be done (however,
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/// in most cases one can construct a dummy expression/item to
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/// substitute; we never hit resolve/type-checking so the dummy
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/// value doesn't have to match anything)
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pub fn span_fatal(&self, sp: Span, msg: &str) -> ! {
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self.print_backtrace();
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self.parse_sess.span_diagnostic.span_fatal(sp, msg);
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}
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/// Emit `msg` attached to `sp`, without immediately stopping
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/// compilation.
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///
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/// Compilation will be stopped in the near future (at the end of
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/// the macro expansion phase).
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pub fn span_err(&self, sp: Span, msg: &str) {
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self.print_backtrace();
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self.parse_sess.span_diagnostic.span_err(sp, msg);
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}
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pub fn span_warn(&self, sp: Span, msg: &str) {
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self.print_backtrace();
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self.parse_sess.span_diagnostic.span_warn(sp, msg);
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}
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pub fn span_unimpl(&self, sp: Span, msg: &str) -> ! {
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self.print_backtrace();
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self.parse_sess.span_diagnostic.span_unimpl(sp, msg);
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}
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pub fn span_bug(&self, sp: Span, msg: &str) -> ! {
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self.print_backtrace();
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self.parse_sess.span_diagnostic.span_bug(sp, msg);
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}
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pub fn span_note(&self, sp: Span, msg: &str) {
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self.print_backtrace();
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self.parse_sess.span_diagnostic.span_note(sp, msg);
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}
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pub fn bug(&self, msg: &str) -> ! {
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self.print_backtrace();
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self.parse_sess.span_diagnostic.handler().bug(msg);
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}
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pub fn trace_macros(&self) -> bool {
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self.trace_mac
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}
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pub fn set_trace_macros(&mut self, x: bool) {
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self.trace_mac = x
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}
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pub fn ident_of(&self, st: &str) -> ast::Ident {
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str_to_ident(st)
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}
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}
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/// Extract a string literal from `expr`, emitting `err_msg` if `expr`
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/// is not a string literal. This does not stop compilation on error,
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/// merely emits a non-fatal error and returns None.
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pub fn expr_to_str(cx: &ExtCtxt, expr: @ast::Expr, err_msg: &str)
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-> Option<(InternedString, ast::StrStyle)> {
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match expr.node {
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ast::ExprLit(l) => match l.node {
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ast::LitStr(ref s, style) => return Some(((*s).clone(), style)),
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_ => cx.span_err(l.span, err_msg)
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},
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_ => cx.span_err(expr.span, err_msg)
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}
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None
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}
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/// Non-fatally assert that `tts` is empty. Note that this function
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/// returns even when `tts` is non-empty, macros that *need* to stop
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/// compilation should call
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/// `cx.parse_sess.span_diagnostic.abort_if_errors()` (this should be
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/// done as rarely as possible).
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pub fn check_zero_tts(cx: &ExtCtxt,
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sp: Span,
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tts: &[ast::TokenTree],
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name: &str) {
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if tts.len() != 0 {
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cx.span_err(sp, format!("{} takes no arguments", name));
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}
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}
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/// Extract the string literal from the first token of `tts`. If this
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/// is not a string literal, emit an error and return None.
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pub fn get_single_str_from_tts(cx: &ExtCtxt,
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sp: Span,
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tts: &[ast::TokenTree],
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name: &str)
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-> Option<~str> {
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if tts.len() != 1 {
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cx.span_err(sp, format!("{} takes 1 argument.", name));
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} else {
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match tts[0] {
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ast::TTTok(_, token::LIT_STR(ident))
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| ast::TTTok(_, token::LIT_STR_RAW(ident, _)) => {
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return Some(token::get_ident(ident).get().to_str())
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}
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_ => cx.span_err(sp, format!("{} requires a string.", name)),
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}
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}
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None
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}
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/// Extract comma-separated expressions from `tts`. If there is a
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/// parsing error, emit a non-fatal error and return None.
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pub fn get_exprs_from_tts(cx: &ExtCtxt,
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sp: Span,
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tts: &[ast::TokenTree]) -> Option<~[@ast::Expr]> {
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let mut p = parse::new_parser_from_tts(cx.parse_sess(),
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cx.cfg(),
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tts.to_owned());
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let mut es = ~[];
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while p.token != token::EOF {
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if es.len() != 0 && !p.eat(&token::COMMA) {
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cx.span_err(sp, "expected token: `,`");
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return None;
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}
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es.push(p.parse_expr());
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}
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Some(es)
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}
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// in order to have some notion of scoping for macros,
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// we want to implement the notion of a transformation
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// environment.
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// This environment maps Names to SyntaxExtensions.
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// Actually, the following implementation is parameterized
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// by both key and value types.
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//impl question: how to implement it? Initially, the
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// env will contain only macros, so it might be painful
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// to add an empty frame for every context. Let's just
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// get it working, first....
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// NB! the mutability of the underlying maps means that
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// if expansion is out-of-order, a deeper scope may be
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// able to refer to a macro that was added to an enclosing
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// scope lexically later than the deeper scope.
|
|
|
|
struct MapChainFrame {
|
|
info: BlockInfo,
|
|
map: HashMap<Name, SyntaxExtension>,
|
|
}
|
|
|
|
#[unsafe_destructor]
|
|
impl Drop for MapChainFrame {
|
|
fn drop(&mut self) {
|
|
// make sure that syntax extension dtors run before we drop the libs
|
|
self.map.clear();
|
|
}
|
|
}
|
|
|
|
// Only generic to make it easy to test
|
|
pub struct SyntaxEnv {
|
|
priv chain: ~[MapChainFrame],
|
|
}
|
|
|
|
impl SyntaxEnv {
|
|
pub fn new() -> SyntaxEnv {
|
|
let mut map = SyntaxEnv { chain: ~[] };
|
|
map.push_frame();
|
|
map
|
|
}
|
|
|
|
pub fn push_frame(&mut self) {
|
|
self.chain.push(MapChainFrame {
|
|
info: BlockInfo::new(),
|
|
map: HashMap::new(),
|
|
});
|
|
}
|
|
|
|
pub fn pop_frame(&mut self) {
|
|
assert!(self.chain.len() > 1, "too many pops on MapChain!");
|
|
self.chain.pop();
|
|
}
|
|
|
|
fn find_escape_frame<'a>(&'a mut self) -> &'a mut MapChainFrame {
|
|
for (i, frame) in self.chain.mut_iter().enumerate().rev() {
|
|
if !frame.info.macros_escape || i == 0 {
|
|
return frame
|
|
}
|
|
}
|
|
unreachable!()
|
|
}
|
|
|
|
pub fn find<'a>(&'a self, k: &Name) -> Option<&'a SyntaxExtension> {
|
|
for frame in self.chain.iter().rev() {
|
|
match frame.map.find(k) {
|
|
Some(v) => return Some(v),
|
|
None => {}
|
|
}
|
|
}
|
|
None
|
|
}
|
|
|
|
pub fn insert(&mut self, k: Name, v: SyntaxExtension) {
|
|
self.find_escape_frame().map.insert(k, v);
|
|
}
|
|
|
|
pub fn info<'a>(&'a mut self) -> &'a mut BlockInfo {
|
|
&mut self.chain[self.chain.len()-1].info
|
|
}
|
|
}
|