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Simplify

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This commit is contained in:
Lukas Wirth 2022-01-02 02:39:14 +01:00
parent 809461cc42
commit a0e0e4575b
4 changed files with 47 additions and 59 deletions
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80
crates/mbe/src/lib.rs
View File

@ -27,6 +27,14 @@ use crate::{
pub use ::parser::TopEntryPoint;
pub use tt::{Delimiter, DelimiterKind, Punct};
pub use crate::{
syntax_bridge::{
parse_exprs_with_sep, parse_to_token_tree, syntax_node_to_token_tree,
syntax_node_to_token_tree_censored, token_tree_to_syntax_node,
},
token_map::TokenMap,
};
#[derive(Debug, PartialEq, Eq, Clone)]
pub enum ParseError {
UnexpectedToken(String),
@ -70,14 +78,6 @@ impl fmt::Display for ExpandError {
}
}
pub use crate::{
syntax_bridge::{
parse_exprs_with_sep, parse_to_token_tree, syntax_node_to_token_tree,
syntax_node_to_token_tree_censored, token_tree_to_syntax_node,
},
token_map::TokenMap,
};
/// This struct contains AST for a single `macro_rules` definition. What might
/// be very confusing is that AST has almost exactly the same shape as
/// `tt::TokenTree`, but there's a crucial difference: in macro rules, `$ident`
@ -121,11 +121,9 @@ impl Shift {
}
}
tt::TokenTree::Leaf(leaf) => {
let id = match leaf {
tt::Leaf::Literal(it) => it.id,
tt::Leaf::Punct(it) => it.id,
tt::Leaf::Ident(it) => it.id,
};
let &(tt::Leaf::Ident(tt::Ident { id, .. })
| tt::Leaf::Punct(tt::Punct { id, .. })
| tt::Leaf::Literal(tt::Literal { id, .. })) = leaf;
(id != tt::TokenId::unspecified()).then(|| id.0)
}
@ -138,15 +136,15 @@ impl Shift {
pub fn shift_all(self, tt: &mut tt::Subtree) {
for t in &mut tt.token_trees {
match t {
tt::TokenTree::Leaf(leaf) => match leaf {
tt::Leaf::Ident(ident) => ident.id = self.shift(ident.id),
tt::Leaf::Punct(punct) => punct.id = self.shift(punct.id),
tt::Leaf::Literal(lit) => lit.id = self.shift(lit.id),
},
tt::TokenTree::Leaf(
tt::Leaf::Ident(tt::Ident { id, .. })
| tt::Leaf::Punct(tt::Punct { id, .. })
| tt::Leaf::Literal(tt::Literal { id, .. }),
) => *id = self.shift(*id),
tt::TokenTree::Subtree(tt) => {
if let Some(it) = tt.delimiter.as_mut() {
it.id = self.shift(it.id);
};
}
self.shift_all(tt)
}
}
@ -155,10 +153,11 @@ impl Shift {
pub fn shift(self, id: tt::TokenId) -> tt::TokenId {
if id == tt::TokenId::unspecified() {
return id;
}
id
} else {
tt::TokenId(id.0 + self.0)
}
}
pub fn unshift(self, id: tt::TokenId) -> Option<tt::TokenId> {
id.0.checked_sub(self.0).map(tt::TokenId)
@ -190,8 +189,8 @@ impl DeclarativeMacro {
}
}
for rule in &rules {
validate(&rule.lhs)?;
for Rule { lhs, .. } in &rules {
validate(lhs)?;
}
Ok(DeclarativeMacro { rules, shift: Shift::new(tt) })
@ -220,12 +219,13 @@ impl DeclarativeMacro {
cov_mark::hit!(parse_macro_def_simple);
let rule = Rule::parse(&mut src, false)?;
if src.len() != 0 {
return Err(ParseError::Expected("remain tokens in macro def".to_string()));
return Err(ParseError::Expected("remaining tokens in macro def".to_string()));
}
rules.push(rule);
}
for rule in &rules {
validate(&rule.lhs)?;
for Rule { lhs, .. } in &rules {
validate(lhs)?;
}
Ok(DeclarativeMacro { rules, shift: Shift::new(tt) })
@ -281,28 +281,18 @@ fn validate(pattern: &MetaTemplate) -> Result<(), ParseError> {
Op::Repeat { tokens: subtree, separator, .. } => {
// Checks that no repetition which could match an empty token
// https://github.com/rust-lang/rust/blob/a58b1ed44f5e06976de2bdc4d7dc81c36a96934f/src/librustc_expand/mbe/macro_rules.rs#L558
if separator.is_none()
&& subtree.iter().all(|child_op| {
let lsh_is_empty_seq = separator.is_none() && subtree.iter().all(|child_op| {
match child_op {
Op::Var { kind, .. } => {
// vis is optional
if kind.as_ref().map_or(false, |it| it == "vis") {
return true;
Op::Var { kind: Some(kind), .. } => kind == "vis",
Op::Repeat {
kind: parser::RepeatKind::ZeroOrMore | parser::RepeatKind::ZeroOrOne,
..
} => true,
_ => false,
}
}
Op::Repeat { kind, .. } => {
return matches!(
kind,
parser::RepeatKind::ZeroOrMore | parser::RepeatKind::ZeroOrOne
)
}
Op::Leaf(_) => {}
Op::Subtree { .. } => {}
}
false
})
{
});
if lsh_is_empty_seq {
return Err(ParseError::RepetitionEmptyTokenTree);
}
validate(subtree)?

10
crates/mbe/src/parser.rs
View File

@ -76,9 +76,9 @@ impl PartialEq for Separator {
use Separator::*;
match (self, other) {
(Ident(ref a), Ident(ref b)) => a.text == b.text,
(Literal(ref a), Literal(ref b)) => a.text == b.text,
(Puncts(ref a), Puncts(ref b)) if a.len() == b.len() => {
(Ident(a), Ident(b)) => a.text == b.text,
(Literal(a), Literal(b)) => a.text == b.text,
(Puncts(a), Puncts(b)) if a.len() == b.len() => {
let a_iter = a.iter().map(|a| a.char);
let b_iter = b.iter().map(|b| b.char);
a_iter.eq(b_iter)
@ -131,9 +131,7 @@ fn next_op<'a>(first: &tt::TokenTree, src: &mut TtIter<'a>, mode: Mode) -> Resul
Op::Repeat { tokens, separator, kind }
}
tt::TokenTree::Leaf(leaf) => match leaf {
tt::Leaf::Punct(_) => {
return Err(ParseError::Expected("ident".to_string()));
}
tt::Leaf::Punct(_) => return Err(ParseError::Expected("ident".to_string())),
tt::Leaf::Ident(ident) if ident.text == "crate" => {
// We simply produce identifier `$crate` here. And it will be resolved when lowering ast to Path.
Op::Leaf(tt::Leaf::from(tt::Ident { text: "$crate".into(), id: ident.id }))

4
crates/mbe/src/syntax_bridge.rs
View File

@ -81,7 +81,7 @@ pub fn parse_to_token_tree(text: &str) -> Option<(tt::Subtree, TokenMap)> {
}
let mut conv = RawConvertor {
lexed: lexed,
lexed,
pos: 0,
id_alloc: TokenIdAlloc {
map: Default::default(),
@ -147,8 +147,8 @@ fn convert_tokens<C: TokenConvertor>(conv: &mut C) -> tt::Subtree {
let entry = stack.last_mut().unwrap();
let result = &mut entry.subtree.token_trees;
let (token, range) = match conv.bump() {
None => break,
Some(it) => it,
None => break,
};
let k: SyntaxKind = token.kind(&conv);

6
crates/mbe/src/tt_iter.rs
View File

@ -1,11 +1,11 @@
//! A "Parser" structure for token trees. We use this when parsing a declarative
//! macro definition into a list of patterns and templates.
use crate::{to_parser_input::to_parser_input, ExpandError, ExpandResult};
use syntax::SyntaxKind;
use tt::buffer::TokenBuffer;
use crate::{to_parser_input::to_parser_input, ExpandError, ExpandResult};
macro_rules! err {
() => {
ExpandError::BindingError(format!(""))
@ -27,7 +27,7 @@ impl<'a> TtIter<'a> {
pub(crate) fn expect_char(&mut self, char: char) -> Result<(), ()> {
match self.next() {
Some(tt::TokenTree::Leaf(tt::Leaf::Punct(tt::Punct { char: c, .. }))) if *c == char => {
Some(&tt::TokenTree::Leaf(tt::Leaf::Punct(tt::Punct { char: c, .. }))) if c == char => {
Ok(())
}
_ => Err(()),