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Merge #1157

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1157: Add mbe stmt matcher r=matklad a=edwin0cheng

Add `stmt` matcher in `ra_mbe` , and added corresponding `stmt()` parser in `ra_syntax`. 
This PR also help PR #1148 for `MarcoKind::Items` parsing.

Note: 
* According [the book](https://doc.rust-lang.org/reference/macros-by-example.html), mbe `stmt` matcher will only match statement without the trailing semicolon 
* `item` is a valid statement.





Co-authored-by: Edwin Cheng <edwin0cheng@gmail.com>
This commit is contained in:
bors[bot] 2019-04-17 05:10:29 +00:00
commit 0e35603069
7 changed files with 136 additions and 89 deletions
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15
crates/ra_mbe/src/lib.rs
View File

@ -582,4 +582,19 @@ macro_rules! foo {
);
assert_expansion(&rules, "foo! { (a, b) }", "fn foo () {let (a , b) ;}");
}
#[test]
fn test_stmt() {
let rules = create_rules(
r#"
macro_rules! foo {
($ i:stmt) => (
fn bar() { $ i; }
)
}
"#,
);
assert_expansion(&rules, "foo! { 2 }", "fn bar () {2 ;}");
assert_expansion(&rules, "foo! { let a = 0 }", "fn bar () {let a = 0 ;}");
}
}

4
crates/ra_mbe/src/mbe_expander.rs
View File

@ -157,6 +157,10 @@ fn match_lhs(pattern: &crate::Subtree, input: &mut TtCursor) -> Result<Bindings,
let pat = input.eat_pat().ok_or(ExpandError::UnexpectedToken)?.clone();
res.inner.insert(text.clone(), Binding::Simple(pat.into()));
}
"stmt" => {
let pat = input.eat_stmt().ok_or(ExpandError::UnexpectedToken)?.clone();
res.inner.insert(text.clone(), Binding::Simple(pat.into()));
}
_ => return Err(ExpandError::UnexpectedToken),
}
}

4
crates/ra_mbe/src/subtree_parser.rs
View File

@ -42,6 +42,10 @@ pub fn parse_pat(self) -> Option<tt::TokenTree> {
self.parse(ra_parser::parse_pat)
}
pub fn parse_stmt(self) -> Option<tt::TokenTree> {
self.parse(|src, sink| ra_parser::parse_stmt(src, sink, false))
}
fn parse<F>(self, f: F) -> Option<tt::TokenTree>
where
F: FnOnce(&dyn TokenSource, &mut dyn TreeSink),

5
crates/ra_mbe/src/tt_cursor.rs
View File

@ -99,6 +99,11 @@ pub(crate) fn eat_pat(&mut self) -> Option<tt::TokenTree> {
parser.parse_pat()
}
pub(crate) fn eat_stmt(&mut self) -> Option<tt::TokenTree> {
let parser = Parser::new(&mut self.pos, self.subtree);
parser.parse_stmt()
}
pub(crate) fn expect_char(&mut self, char: char) -> Result<(), ParseError> {
if self.at_char(char) {
self.bump();

4
crates/ra_parser/src/grammar.rs
View File

@ -65,6 +65,10 @@ pub(crate) fn pattern(p: &mut Parser) {
patterns::pattern(p)
}
pub(crate) fn stmt(p: &mut Parser, with_semi: bool) {
expressions::stmt(p, with_semi)
}
pub(crate) fn reparser(
node: SyntaxKind,
first_child: Option<SyntaxKind>,

188
crates/ra_parser/src/grammar/expressions.rs
View File

@ -48,6 +48,104 @@ fn is_expr_stmt_attr_allowed(kind: SyntaxKind) -> bool {
}
}
pub(super) fn stmt(p: &mut Parser, with_semi: bool) {
// test block_items
// fn a() { fn b() {} }
let m = p.start();
// test attr_on_expr_stmt
// fn foo() {
// #[A] foo();
// #[B] bar!{}
// #[C] #[D] {}
// #[D] return ();
// }
let has_attrs = p.at(POUND);
attributes::outer_attributes(p);
if p.at(LET_KW) {
let_stmt(p, m, with_semi);
return;
}
let m = match items::maybe_item(p, m, items::ItemFlavor::Mod) {
Ok(()) => return,
Err(m) => m,
};
let (cm, blocklike) = expr_stmt(p);
let kind = cm.as_ref().map(|cm| cm.kind()).unwrap_or(ERROR);
if has_attrs && !is_expr_stmt_attr_allowed(kind) {
// test_err attr_on_expr_not_allowed
// fn foo() {
// #[A] 1 + 2;
// #[B] if true {};
// }
p.error(format!("attributes are not allowed on {:?}", kind));
}
if p.at(R_CURLY) {
// test attr_on_last_expr_in_block
// fn foo() {
// { #[A] bar!()? }
// #[B] &()
// }
if let Some(cm) = cm {
cm.undo_completion(p).abandon(p);
m.complete(p, kind);
} else {
m.abandon(p);
}
} else {
// test no_semi_after_block
// fn foo() {
// if true {}
// loop {}
// match () {}
// while true {}
// for _ in () {}
// {}
// {}
// macro_rules! test {
// () => {}
// }
// test!{}
// }
if with_semi {
if blocklike.is_block() {
p.eat(SEMI);
} else {
p.expect(SEMI);
}
}
m.complete(p, EXPR_STMT);
}
// test let_stmt;
// fn foo() {
// let a;
// let b: i32;
// let c = 92;
// let d: i32 = 92;
// }
fn let_stmt(p: &mut Parser, m: Marker, with_semi: bool) {
assert!(p.at(LET_KW));
p.bump();
patterns::pattern(p);
if p.at(COLON) {
types::ascription(p);
}
if p.eat(EQ) {
expressions::expr(p);
}
if with_semi {
p.expect(SEMI);
}
m.complete(p, LET_STMT);
}
}
pub(crate) fn expr_block_contents(p: &mut Parser) {
// This is checked by a validator
attributes::inner_attributes(p);
@ -62,95 +160,7 @@ pub(crate) fn expr_block_contents(p: &mut Parser) {
continue;
}
// test block_items
// fn a() { fn b() {} }
let m = p.start();
// test attr_on_expr_stmt
// fn foo() {
// #[A] foo();
// #[B] bar!{}
// #[C] #[D] {}
// #[D] return ();
// }
let has_attrs = p.at(POUND);
attributes::outer_attributes(p);
if p.at(LET_KW) {
let_stmt(p, m);
continue;
}
let m = match items::maybe_item(p, m, items::ItemFlavor::Mod) {
Ok(()) => continue,
Err(m) => m,
};
let (cm, blocklike) = expr_stmt(p);
let kind = cm.as_ref().map(|cm| cm.kind()).unwrap_or(ERROR);
if has_attrs && !is_expr_stmt_attr_allowed(kind) {
// test_err attr_on_expr_not_allowed
// fn foo() {
// #[A] 1 + 2;
// #[B] if true {};
// }
p.error(format!("attributes are not allowed on {:?}", kind));
}
if p.at(R_CURLY) {
// test attr_on_last_expr_in_block
// fn foo() {
// { #[A] bar!()? }
// #[B] &()
// }
if let Some(cm) = cm {
cm.undo_completion(p).abandon(p);
m.complete(p, kind);
} else {
m.abandon(p);
}
} else {
// test no_semi_after_block
// fn foo() {
// if true {}
// loop {}
// match () {}
// while true {}
// for _ in () {}
// {}
// {}
// macro_rules! test {
// () => {}
// }
// test!{}
// }
if blocklike.is_block() {
p.eat(SEMI);
} else {
p.expect(SEMI);
}
m.complete(p, EXPR_STMT);
}
}
// test let_stmt;
// fn foo() {
// let a;
// let b: i32;
// let c = 92;
// let d: i32 = 92;
// }
fn let_stmt(p: &mut Parser, m: Marker) {
assert!(p.at(LET_KW));
p.bump();
patterns::pattern(p);
if p.at(COLON) {
types::ascription(p);
}
if p.eat(EQ) {
expressions::expr(p);
}
p.expect(SEMI);
m.complete(p, LET_STMT);
stmt(p, true)
}
}

5
crates/ra_parser/src/lib.rs
View File

@ -88,6 +88,11 @@ pub fn parse_pat(token_source: &dyn TokenSource, tree_sink: &mut dyn TreeSink) {
parse_from_tokens(token_source, tree_sink, grammar::pattern);
}
/// Parse given tokens into the given sink as a statement
pub fn parse_stmt(token_source: &dyn TokenSource, tree_sink: &mut dyn TreeSink, with_semi: bool) {
parse_from_tokens(token_source, tree_sink, |p| grammar::stmt(p, with_semi));
}
/// A parsing function for a specific braced-block.
pub struct Reparser(fn(&mut parser::Parser));