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import either::{either, left, right};
import ast_util::spanned;
import common::{parser_common, seq_sep};
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>>;
impl parser_attr for parser {
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);
if 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);
ret some(left([first_attr] + self.parse_outer_attributes()));
} else if !(self.look_ahead(1u) == token::LT
|| self.look_ahead(1u) == token::LBRACKET
|| expect_item_next) {
self.bump();
ret some(right(self.parse_syntax_ext_naked(lo)));
} else { ret none; }
} else { ret none; }
}
// Parse attributes that appear before an item
fn parse_outer_attributes() -> [ast::attribute] {
let mut attrs: [ast::attribute] = [];
while self.token == token::POUND
&& self.look_ahead(1u) == token::LBRACKET {
attrs += [self.parse_attribute(ast::attr_outer)];
}
ret attrs;
}
fn parse_attribute(style: ast::attr_style) -> ast::attribute {
let lo = self.span.lo;
self.expect(token::POUND);
ret self.parse_attribute_naked(style, lo);
}
fn parse_attribute_naked(style: ast::attr_style, lo: uint) ->
ast::attribute {
self.expect(token::LBRACKET);
let meta_item = self.parse_meta_item();
self.expect(token::RBRACKET);
let mut hi = self.span.hi;
ret spanned(lo, hi, {style: style, value: *meta_item});
}
// 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] = [];
while 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});
next_outer_attrs += [outer_attr];
break;
}
}
ret {inner: inner_attrs, next: next_outer_attrs};
}
fn parse_meta_item() -> @ast::meta_item {
let lo = self.span.lo;
let ident = self.parse_ident();
alt self.token {
token::EQ {
self.bump();
let lit = self.parse_lit();
let mut hi = self.span.hi;
ret @spanned(lo, hi, ast::meta_name_value(ident, lit));
}
token::LPAREN {
let inner_items = self.parse_meta_seq();
let mut hi = self.span.hi;
ret @spanned(lo, hi, ast::meta_list(ident, inner_items));
}
_ {
let mut hi = self.span.hi;
ret @spanned(lo, hi, ast::meta_word(ident));
}
}
}
fn parse_meta_seq() -> [@ast::meta_item] {
ret self.parse_seq(token::LPAREN, token::RPAREN,
seq_sep(token::COMMA),
{|p| p.parse_meta_item()}).node;
}
fn parse_optional_meta() -> [@ast::meta_item] {
alt self.token { token::LPAREN { ret self.parse_meta_seq(); }
_ { ret []; } }
}
}
//
// Local Variables:
// mode: rust
// fill-column: 78;
// indent-tabs-mode: nil
// c-basic-offset: 4
// buffer-file-coding-system: utf-8-unix
// End:
//
|
