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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 either::{Either, Left, Right};
use ast_util::spanned;
use common::*; //resolve bug?
export attr_or_ext;
export parser_attr;
// A type to distingush between the parsing of item attributes or syntax
// extensions, which both begin with token.POUND
type attr_or_ext = Option<Either<~[ast::attribute], @ast::expr>>;
trait parser_attr {
fn parse_outer_attrs_or_ext(first_item_attrs: ~[ast::attribute])
-> attr_or_ext;
fn parse_outer_attributes() -> ~[ast::attribute];
fn parse_attribute(style: ast::attr_style) -> ast::attribute;
fn parse_attribute_naked(style: ast::attr_style, lo: BytePos) ->
ast::attribute;
fn parse_inner_attrs_and_next() ->
{inner: ~[ast::attribute], next: ~[ast::attribute]};
fn parse_meta_item() -> @ast::meta_item;
fn parse_meta_seq() -> ~[@ast::meta_item];
fn parse_optional_meta() -> ~[@ast::meta_item];
}
impl Parser: parser_attr {
fn parse_outer_attrs_or_ext(first_item_attrs: ~[ast::attribute])
-> attr_or_ext
{
let expect_item_next = vec::is_not_empty(first_item_attrs);
match self.token {
token::POUND => {
let lo = self.span.lo;
if self.look_ahead(1u) == token::LBRACKET {
self.bump();
let first_attr =
self.parse_attribute_naked(ast::attr_outer, lo);
return Some(Left(vec::append(~[first_attr],
self.parse_outer_attributes())));
} else if !(self.look_ahead(1u) == token::LT
|| self.look_ahead(1u) == token::LBRACKET
|| self.look_ahead(1u) == token::POUND
|| expect_item_next) {
self.bump();
return Some(Right(self.parse_syntax_ext_naked(lo)));
} else { return None; }
}
token::DOC_COMMENT(_) => {
return Some(Left(self.parse_outer_attributes()));
}
_ => return None
}
}
// Parse attributes that appear before an item
fn parse_outer_attributes() -> ~[ast::attribute] {
let mut attrs: ~[ast::attribute] = ~[];
loop {
match copy self.token {
token::POUND => {
if self.look_ahead(1u) != token::LBRACKET {
break;
}
attrs += ~[self.parse_attribute(ast::attr_outer)];
}
token::DOC_COMMENT(s) => {
let attr = ::attr::mk_sugared_doc_attr(
*self.id_to_str(s), self.span.lo, self.span.hi);
if attr.node.style != ast::attr_outer {
self.fatal(~"expected outer comment");
}
attrs += ~[attr];
self.bump();
}
_ => break
}
}
return attrs;
}
fn parse_attribute(style: ast::attr_style) -> ast::attribute {
let lo = self.span.lo;
self.expect(token::POUND);
return self.parse_attribute_naked(style, lo);
}
fn parse_attribute_naked(style: ast::attr_style, lo: BytePos) ->
ast::attribute {
self.expect(token::LBRACKET);
let meta_item = self.parse_meta_item();
self.expect(token::RBRACKET);
let mut hi = self.span.hi;
return spanned(lo, hi, {style: style, value: *meta_item,
is_sugared_doc: false});
}
// Parse attributes that appear after the opening of an item, each
// terminated by a semicolon. In addition to a vector of inner attributes,
// this function also returns a vector that may contain the first outer
// attribute of the next item (since we can't know whether the attribute
// is an inner attribute of the containing item or an outer attribute of
// the first contained item until we see the semi).
fn parse_inner_attrs_and_next() ->
{inner: ~[ast::attribute], next: ~[ast::attribute]} {
let mut inner_attrs: ~[ast::attribute] = ~[];
let mut next_outer_attrs: ~[ast::attribute] = ~[];
loop {
match copy self.token {
token::POUND => {
if self.look_ahead(1u) != token::LBRACKET {
// This is an extension
break;
}
let attr = self.parse_attribute(ast::attr_inner);
if self.token == token::SEMI {
self.bump();
inner_attrs += ~[attr];
} else {
// It's not really an inner attribute
let outer_attr =
spanned(attr.span.lo, attr.span.hi,
{style: ast::attr_outer, value: attr.node.value,
is_sugared_doc: false});
next_outer_attrs += ~[outer_attr];
break;
}
}
token::DOC_COMMENT(s) => {
let attr = ::attr::mk_sugared_doc_attr(
*self.id_to_str(s), self.span.lo, self.span.hi);
self.bump();
if attr.node.style == ast::attr_inner {
inner_attrs += ~[attr];
} else {
next_outer_attrs += ~[attr];
break;
}
}
_ => break
}
}
return {inner: inner_attrs, next: next_outer_attrs};
}
fn parse_meta_item() -> @ast::meta_item {
let lo = self.span.lo;
let name = *self.id_to_str(self.parse_ident());
match self.token {
token::EQ => {
self.bump();
let lit = self.parse_lit();
let mut hi = self.span.hi;
return @spanned(lo, hi, ast::meta_name_value(name, lit));
}
token::LPAREN => {
let inner_items = self.parse_meta_seq();
let mut hi = self.span.hi;
return @spanned(lo, hi, ast::meta_list(name, inner_items));
}
_ => {
let mut hi = self.span.hi;
return @spanned(lo, hi, ast::meta_word(name));
}
}
}
fn parse_meta_seq() -> ~[@ast::meta_item] {
return self.parse_seq(token::LPAREN, token::RPAREN,
seq_sep_trailing_disallowed(token::COMMA),
|p| p.parse_meta_item()).node;
}
fn parse_optional_meta() -> ~[@ast::meta_item] {
match self.token {
token::LPAREN => return self.parse_meta_seq(),
_ => return ~[]
}
}
}
//
// Local Variables:
// mode: rust
// fill-column: 78;
// indent-tabs-mode: nil
// c-basic-offset: 4
// buffer-file-coding-system: utf-8-unix
// End:
//
|
