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Rollup merge of #33044 - petrochenkov:prefix, r=eddyb

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syntax: Parse import prefixes as paths

Fixes https://github.com/rust-lang/rust/issues/10415

r? @eddyb
(This partially intersects with https://github.com/rust-lang/rust/pull/33041)
This commit is contained in:
Manish Goregaokar 2016-04-17 17:50:35 +05:30
commit 02e40d910a
9 changed files with 224 additions and 134 deletions
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174
src/libsyntax/parse/parser.rs
View file

@ -81,6 +81,8 @@ type ItemInfo = (Ident, ItemKind, Option<Vec<Attribute> >);
pub enum PathParsingMode {
/// A path with no type parameters; e.g. `foo::bar::Baz`
NoTypesAllowed,
/// Same as `NoTypesAllowed`, but may end with `::{` or `::*`, which are left unparsed
ImportPrefix,
/// A path with a lifetime and type parameters, with no double colons
/// before the type parameters; e.g. `foo::bar<'a>::Baz<T>`
LifetimeAndTypesWithoutColons,
@ -591,20 +593,6 @@ impl<'a> Parser<'a> {
}
}
pub fn parse_path_list_item(&mut self) -> PResult<'a, ast::PathListItem> {
let lo = self.span.lo;
let node = if self.eat_keyword(keywords::SelfValue) {
let rename = self.parse_rename()?;
ast::PathListItemKind::Mod { id: ast::DUMMY_NODE_ID, rename: rename }
} else {
let ident = self.parse_ident()?;
let rename = self.parse_rename()?;
ast::PathListItemKind::Ident { name: ident, rename: rename, id: ast::DUMMY_NODE_ID }
};
let hi = self.last_span.hi;
Ok(spanned(lo, hi, node))
}
/// Check if the next token is `tok`, and return `true` if so.
///
/// This method will automatically add `tok` to `expected_tokens` if `tok` is not
@ -1763,8 +1751,8 @@ impl<'a> Parser<'a> {
LifetimeAndTypesWithColons => {
self.parse_path_segments_with_colons()?
}
NoTypesAllowed => {
self.parse_path_segments_without_types()?
NoTypesAllowed | ImportPrefix => {
self.parse_path_segments_without_types(mode == ImportPrefix)?
}
};
path.segments.extend(segments);
@ -1801,8 +1789,8 @@ impl<'a> Parser<'a> {
LifetimeAndTypesWithColons => {
self.parse_path_segments_with_colons()?
}
NoTypesAllowed => {
self.parse_path_segments_without_types()?
NoTypesAllowed | ImportPrefix => {
self.parse_path_segments_without_types(mode == ImportPrefix)?
}
};
@ -1920,7 +1908,8 @@ impl<'a> Parser<'a> {
/// Examples:
/// - `a::b::c`
pub fn parse_path_segments_without_types(&mut self) -> PResult<'a, Vec<ast::PathSegment>> {
pub fn parse_path_segments_without_types(&mut self, import_prefix: bool)
-> PResult<'a, Vec<ast::PathSegment>> {
let mut segments = Vec::new();
loop {
// First, parse an identifier.
@ -1932,9 +1921,11 @@ impl<'a> Parser<'a> {
parameters: ast::PathParameters::none()
});
// If we do not see a `::`, stop.
if !self.eat(&token::ModSep) {
// If we do not see a `::` or see `::{`/`::*`, stop.
if !self.check(&token::ModSep) || import_prefix && self.is_import_coupler() {
return Ok(segments);
} else {
self.bump();
}
}
}
@ -6127,106 +6118,67 @@ impl<'a> Parser<'a> {
self.parse_item_(attrs, true, false)
}
fn parse_path_list_items(&mut self) -> PResult<'a, Vec<ast::PathListItem>> {
self.parse_unspanned_seq(&token::OpenDelim(token::Brace),
&token::CloseDelim(token::Brace),
SeqSep::trailing_allowed(token::Comma), |this| {
let lo = this.span.lo;
let node = if this.eat_keyword(keywords::SelfValue) {
let rename = this.parse_rename()?;
ast::PathListItemKind::Mod { id: ast::DUMMY_NODE_ID, rename: rename }
} else {
let ident = this.parse_ident()?;
let rename = this.parse_rename()?;
ast::PathListItemKind::Ident { name: ident, rename: rename, id: ast::DUMMY_NODE_ID }
};
let hi = this.last_span.hi;
Ok(spanned(lo, hi, node))
})
}
/// Matches view_path : MOD? non_global_path as IDENT
/// | MOD? non_global_path MOD_SEP LBRACE RBRACE
/// | MOD? non_global_path MOD_SEP LBRACE ident_seq RBRACE
/// | MOD? non_global_path MOD_SEP STAR
/// | MOD? non_global_path
/// `::{` or `::*`
fn is_import_coupler(&mut self) -> bool {
self.check(&token::ModSep) &&
self.look_ahead(1, |t| *t == token::OpenDelim(token::Brace) ||
*t == token::BinOp(token::Star))
}
/// Matches ViewPath:
/// MOD_SEP? non_global_path
/// MOD_SEP? non_global_path as IDENT
/// MOD_SEP? non_global_path MOD_SEP STAR
/// MOD_SEP? non_global_path MOD_SEP LBRACE item_seq RBRACE
/// MOD_SEP? LBRACE item_seq RBRACE
fn parse_view_path(&mut self) -> PResult<'a, P<ViewPath>> {
let lo = self.span.lo;
// Allow a leading :: because the paths are absolute either way.
// This occurs with "use $crate::..." in macros.
let is_global = self.eat(&token::ModSep);
if self.check(&token::OpenDelim(token::Brace)) {
// use {foo,bar}
let idents = self.parse_unspanned_seq(
&token::OpenDelim(token::Brace),
&token::CloseDelim(token::Brace),
SeqSep::trailing_allowed(token::Comma),
|p| p.parse_path_list_item())?;
let path = ast::Path {
if self.check(&token::OpenDelim(token::Brace)) || self.is_import_coupler() {
// `{foo, bar}` or `::{foo, bar}`
let prefix = ast::Path {
global: self.eat(&token::ModSep),
segments: Vec::new(),
span: mk_sp(lo, self.span.hi),
global: is_global,
segments: Vec::new()
};
return Ok(P(spanned(lo, self.span.hi, ViewPathList(path, idents))));
}
let first_ident = self.parse_ident()?;
let mut path = vec!(first_ident);
if let token::ModSep = self.token {
// foo::bar or foo::{a,b,c} or foo::*
while self.check(&token::ModSep) {
let items = self.parse_path_list_items()?;
Ok(P(spanned(lo, self.span.hi, ViewPathList(prefix, items))))
} else {
let prefix = self.parse_path(ImportPrefix)?;
if self.is_import_coupler() {
// `foo::bar::{a, b}` or `foo::bar::*`
self.bump();
match self.token {
token::Ident(..) => {
let ident = self.parse_ident()?;
path.push(ident);
}
// foo::bar::{a,b,c}
token::OpenDelim(token::Brace) => {
let idents = self.parse_unspanned_seq(
&token::OpenDelim(token::Brace),
&token::CloseDelim(token::Brace),
SeqSep::trailing_allowed(token::Comma),
|p| p.parse_path_list_item()
)?;
let path = ast::Path {
span: mk_sp(lo, self.span.hi),
global: is_global,
segments: path.into_iter().map(|identifier| {
ast::PathSegment {
identifier: identifier,
parameters: ast::PathParameters::none(),
}
}).collect()
};
return Ok(P(spanned(lo, self.span.hi, ViewPathList(path, idents))));
}
// foo::bar::*
token::BinOp(token::Star) => {
if self.check(&token::BinOp(token::Star)) {
self.bump();
let path = ast::Path {
span: mk_sp(lo, self.span.hi),
global: is_global,
segments: path.into_iter().map(|identifier| {
ast::PathSegment {
identifier: identifier,
parameters: ast::PathParameters::none(),
}
}).collect()
};
return Ok(P(spanned(lo, self.span.hi, ViewPathGlob(path))));
}
// fall-through for case foo::bar::;
token::Semi => {
self.span_err(self.span, "expected identifier or `{` or `*`, found `;`");
}
_ => break
Ok(P(spanned(lo, self.span.hi, ViewPathGlob(prefix))))
} else {
let items = self.parse_path_list_items()?;
Ok(P(spanned(lo, self.span.hi, ViewPathList(prefix, items))))
}
} else {
// `foo::bar` or `foo::bar as baz`
let rename = self.parse_rename()?.
unwrap_or(prefix.segments.last().unwrap().identifier);
Ok(P(spanned(lo, self.last_span.hi, ViewPathSimple(rename, prefix))))
}
}
let mut rename_to = path[path.len() - 1];
let path = ast::Path {
span: mk_sp(lo, self.last_span.hi),
global: is_global,
segments: path.into_iter().map(|identifier| {
ast::PathSegment {
identifier: identifier,
parameters: ast::PathParameters::none(),
}
}).collect()
};
rename_to = self.parse_rename()?.unwrap_or(rename_to);
Ok(P(spanned(lo, self.last_span.hi, ViewPathSimple(rename_to, path))))
}
fn parse_rename(&mut self) -> PResult<'a, Option<Ident>> {