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Support parsing attributes with arbitrary tokens. #111

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Merged
dtolnay merged 12 commits into from
Apr 21, 2017
Merged

Support parsing attributes with arbitrary tokens. #111

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eaa2cff
Support parsing attributes with arbitrary tokens.
Apr 15, 2017
bf395bf
fixup! Only store tokens in Attribute.
Apr 15, 2017
bb25273
fixup! Fixed build on 1.12.1 and 1.13.0
Apr 15, 2017
aebc06e
fixup! Satisfy clippy
Apr 15, 2017
4ded393
fixup! Added tests
Apr 16, 2017
e43b1b0
fixup! Attribute::name -> path
Apr 19, 2017
44d2bf3
fixup! Comments
Apr 19, 2017
0b302a3
fixup! Test for attributes with paths.
Apr 19, 2017
a115eba
fixup! Fix old rust again.
Apr 19, 2017
95f8a7a
fixup! Reinstated name in MetaItem since it's no longer trivial to ge…
Apr 19, 2017
2477061
fixup! Satisfy clippy some more.
Apr 19, 2017
f2dada1
fixup! Attribute paths are mod-style.
Apr 21, 2017
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275 changes: 192 additions & 83 deletions src/attr.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -6,13 +6,111 @@ use std::iter;
#[derive(Debug, Clone, Eq, PartialEq, Hash)]
pub struct Attribute {
pub style: AttrStyle,
pub value: MetaItem,

/// The path of the attribute.
///
/// E.g. `derive` in `#[derive(Copy)]`
/// E.g. `crate::precondition` in `#[crate::precondition x < 5]`
pub path: Path,

/// Any tokens after the path.
///
/// E.g. `( Copy )` in `#[derive(Copy)]`
/// E.g. `x < 5` in `#[crate::precondition x < 5]`
pub tts: Vec<TokenTree>,

pub is_sugared_doc: bool,
}

impl Attribute {
pub fn name(&self) -> &str {
self.value.name()
/// Parses the tokens after the path as a [`MetaItem`](enum.MetaItem.html) if possible.
pub fn meta_item(&self) -> Option<MetaItem> {
let name = if self.path.segments.len() == 1 {
&self.path.segments[0].ident
} else {
return None;
};

if self.tts.is_empty() {
return Some(MetaItem::Word(name.clone()));
}

if self.tts.len() == 1 {
if let TokenTree::Delimited(Delimited { delim: DelimToken::Paren, ref tts }) = self.tts[0] {
fn nested_meta_item_from_tokens(tts: &[TokenTree]) -> Option<(NestedMetaItem, &[TokenTree])> {
assert!(!tts.is_empty());

match tts[0] {
TokenTree::Token(Token::Literal(ref lit)) => {
Some((NestedMetaItem::Literal(lit.clone()), &tts[1..]))
}

TokenTree::Token(Token::Ident(ref ident)) => {
if tts.len() >= 3 {
if let TokenTree::Token(Token::Eq) = tts[1] {
if let TokenTree::Token(Token::Literal(ref lit)) = tts[2] {
return Some((NestedMetaItem::MetaItem(MetaItem::NameValue(ident.clone(), lit.clone())), &tts[3..]));
}
}
}

if tts.len() >= 2 {
if let TokenTree::Delimited(Delimited { delim: DelimToken::Paren, tts: ref inner_tts }) = tts[1] {
return match list_of_nested_meta_items_from_tokens(vec![], inner_tts) {
Some(nested_meta_items) => {
Some((NestedMetaItem::MetaItem(MetaItem::List(ident.clone(), nested_meta_items)), &tts[2..]))
}

None => None
};
}
}

Some((NestedMetaItem::MetaItem(MetaItem::Word(ident.clone())), &tts[1..]))
}

_ => None
}
}

fn list_of_nested_meta_items_from_tokens(mut result: Vec<NestedMetaItem>, tts: &[TokenTree]) -> Option<Vec<NestedMetaItem>> {
if tts.is_empty() {
return Some(result);
}

match nested_meta_item_from_tokens(tts) {
Some((nested_meta_item, rest)) => {
result.push(nested_meta_item);
if rest.is_empty() {
list_of_nested_meta_items_from_tokens(result, rest)
}
else if let TokenTree::Token(Token::Comma) = rest[0] {
list_of_nested_meta_items_from_tokens(result, &rest[1..])
}
else {
None
}
}

None => None
}
}

if let Some(nested_meta_items) = list_of_nested_meta_items_from_tokens(vec![], tts) {
return Some(MetaItem::List(name.clone(), nested_meta_items));
}
}
}

if self.tts.len() == 2 {
if let TokenTree::Token(Token::Eq) = self.tts[0] {
if let TokenTree::Token(Token::Literal(ref lit)) = self.tts[1] {
return Some(MetaItem::NameValue(name.clone(), lit.clone()));
}
}
}

None
}
}

Expand Down Expand Up @@ -109,22 +207,31 @@ impl<'a, T> FilterAttrs<'a> for T
#[cfg(feature = "parsing")]
pub mod parsing {
use super::*;
use ident::parsing::ident;
use lit::parsing::lit;
use lit::{Lit, StrStyle};
use mac::{Token, TokenTree};
use mac::parsing::token_trees;
use synom::space::{block_comment, whitespace};
use ty::parsing::mod_style_path;

#[cfg(feature = "full")]
named!(pub inner_attr -> Attribute, alt!(
do_parse!(
punct!("#") >>
punct!("!") >>
punct!("[") >>
meta_item: meta_item >>
punct!("]") >>
(Attribute {
style: AttrStyle::Inner,
value: meta_item,
is_sugared_doc: false,
path_and_tts: delimited!(
punct!("["),
tuple!(mod_style_path, token_trees),
punct!("]")
) >>
({
let (path, tts) = path_and_tts;

Attribute {
style: AttrStyle::Inner,
path: path,
tts: tts,
is_sugared_doc: false,
}
})
)
|
Expand All @@ -133,10 +240,11 @@ pub mod parsing {
content: take_until!("\n") >>
(Attribute {
style: AttrStyle::Inner,
value: MetaItem::NameValue(
"doc".into(),
format!("//!{}", content).into(),
),
path: "doc".into(),
tts: vec![
TokenTree::Token(Token::Eq),
TokenTree::Token(Token::Literal(Lit::Str(format!("//!{}", content).into(), StrStyle::Cooked))),
],
is_sugared_doc: true,
})
)
Expand All @@ -147,10 +255,11 @@ pub mod parsing {
com: block_comment >>
(Attribute {
style: AttrStyle::Inner,
value: MetaItem::NameValue(
"doc".into(),
com.into(),
),
path: "doc".into(),
tts: vec![
TokenTree::Token(Token::Eq),
TokenTree::Token(Token::Literal(Lit::Str(com.into(), StrStyle::Cooked))),
],
is_sugared_doc: true,
})
)
Expand All @@ -159,13 +268,20 @@ pub mod parsing {
named!(pub outer_attr -> Attribute, alt!(
do_parse!(
punct!("#") >>
punct!("[") >>
meta_item: meta_item >>
punct!("]") >>
(Attribute {
style: AttrStyle::Outer,
value: meta_item,
is_sugared_doc: false,
path_and_tts: delimited!(
punct!("["),
tuple!(mod_style_path, token_trees),
punct!("]")
) >>
({
let (path, tts) = path_and_tts;

Attribute {
style: AttrStyle::Outer,
path: path,
tts: tts,
is_sugared_doc: false,
}
})
)
|
Expand All @@ -175,10 +291,11 @@ pub mod parsing {
content: take_until!("\n") >>
(Attribute {
style: AttrStyle::Outer,
value: MetaItem::NameValue(
"doc".into(),
format!("///{}", content).into(),
),
path: "doc".into(),
tts: vec![
TokenTree::Token(Token::Eq),
TokenTree::Token(Token::Literal(Lit::Str(format!("///{}", content).into(), StrStyle::Cooked))),
],
is_sugared_doc: true,
})
)
Expand All @@ -189,82 +306,74 @@ pub mod parsing {
com: block_comment >>
(Attribute {
style: AttrStyle::Outer,
value: MetaItem::NameValue(
"doc".into(),
com.into(),
),
path: "doc".into(),
tts: vec![
TokenTree::Token(Token::Eq),
TokenTree::Token(Token::Literal(Lit::Str(com.into(), StrStyle::Cooked))),
],
is_sugared_doc: true,
})
)
));

named!(meta_item -> MetaItem, alt!(
do_parse!(
id: ident >>
punct!("(") >>
inner: terminated_list!(punct!(","), nested_meta_item) >>
punct!(")") >>
(MetaItem::List(id, inner))
)
|
do_parse!(
name: ident >>
punct!("=") >>
value: lit >>
(MetaItem::NameValue(name, value))
)
|
map!(ident, MetaItem::Word)
));

named!(nested_meta_item -> NestedMetaItem, alt!(
meta_item => { NestedMetaItem::MetaItem }
|
lit => { NestedMetaItem::Literal }
));
}

#[cfg(feature = "printing")]
mod printing {
use super::*;
use lit::{Lit, StrStyle};
use mac::{Token, TokenTree};
use quote::{Tokens, ToTokens};
use ty::Path;

impl ToTokens for Attribute {
fn to_tokens(&self, tokens: &mut Tokens) {
if let Attribute { style,
value: MetaItem::NameValue(ref name,
Lit::Str(ref value, StrStyle::Cooked)),
is_sugared_doc: true } = *self {
if name == "doc" {
match style {
AttrStyle::Inner if value.starts_with("//!") => {
tokens.append(&format!("{}\n", value));
return;
}
AttrStyle::Inner if value.starts_with("/*!") => {
tokens.append(value);
return;
}
AttrStyle::Outer if value.starts_with("///") => {
tokens.append(&format!("{}\n", value));
return;
}
AttrStyle::Outer if value.starts_with("/**") => {
tokens.append(value);
return;
// If this was a sugared doc, emit it in its original form instead of `#[doc = "..."]`
match *self {
Attribute {
style,
path: Path { global: false, ref segments },
ref tts,
is_sugared_doc: true,
} if segments.len() == 1 &&
segments[0].ident == "doc" &&
segments[0].parameters.is_empty() &&
tts.len() == 2 =>
{
if let TokenTree::Token(Token::Eq) = self.tts[0] {
if let TokenTree::Token(Token::Literal(Lit::Str(ref value, StrStyle::Cooked))) = self.tts[1] {
match style {
AttrStyle::Inner if value.starts_with("//!") => {
tokens.append(&format!("{}\n", value));
return;
}
AttrStyle::Inner if value.starts_with("/*!") => {
tokens.append(value);
return;
}
AttrStyle::Outer if value.starts_with("///") => {
tokens.append(&format!("{}\n", value));
return;
}
AttrStyle::Outer if value.starts_with("/**") => {
tokens.append(value);
return;
}
_ => {}
}
}
_ => {}
}
}

_ => {}
}

tokens.append("#");
if let AttrStyle::Inner = self.style {
tokens.append("!");
}
tokens.append("[");
self.value.to_tokens(tokens);
self.path.to_tokens(tokens);
tokens.append_all(&self.tts);
tokens.append("]");
}
}
Expand Down
21 changes: 21 additions & 0 deletions src/ty.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -519,6 +519,27 @@ pub mod parsing {
), Into::into)
));

named!(pub mod_style_path -> Path, do_parse!(
global: option!(punct!("::")) >>
segments: separated_nonempty_list!(punct!("::"), mod_style_path_segment) >>
(Path {
global: global.is_some(),
segments: segments,
})
));

named!(mod_style_path_segment -> PathSegment, alt!(
map!(ident, Into::into)
|
map!(alt!(
keyword!("super")
|
keyword!("self")
|
keyword!("Self")
), Into::into)
));

named!(type_binding -> TypeBinding, do_parse!(
id: ident >>
punct!("=") >>
Expand Down
3 changes: 2 additions & 1 deletion tests/test_generics.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -21,7 +21,8 @@ fn test_split_for_impl() {
ty_params: vec![TyParam {
attrs: vec![Attribute {
style: AttrStyle::Outer,
value: MetaItem::Word("may_dangle".into()),
path: "may_dangle".into(),
tts: vec![],
is_sugared_doc: false,
}],
ident: Ident::new("T"),
Expand Down
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