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grammar: for predicates in where

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closes #191
This commit is contained in:
Aleksey Kladov
2018-11-05 11:24:02 +03:00
parent 576b9a0727
commit 9010cb9839
4 changed files with 130 additions and 36 deletions
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5
crates/ra_syntax/src/grammar/mod.rs
View File

@@ -21,6 +21,11 @@
//! After adding a new inline-test, run `cargo collect-tests` to extract
//! it as a standalone text-fixture into `tests/data/parser/inline`, and
//! run `cargo test` once to create the "gold" value.
//!
//! Coding convention: rules like `where_clause` always produce either a
//! node or an error, rules like `opt_where_clause` may produce nothing.
//! Non-opt rules typically start with `assert!(p.at(FIRST_TOKEN))`, the
//! caller is responsible for branching on the first token.
mod attributes;
mod expressions;
mod items;

99
crates/ra_syntax/src/grammar/type_params.rs
View File

@@ -4,6 +4,11 @@ pub(super) fn opt_type_param_list(p: &mut Parser) {
if !p.at(L_ANGLE) {
return;
}
type_param_list(p);
}
fn type_param_list(p: &mut Parser) {
assert!(p.at(L_ANGLE));
let m = p.start();
p.bump();
@@ -19,32 +24,32 @@ pub(super) fn opt_type_param_list(p: &mut Parser) {
}
p.expect(R_ANGLE);
m.complete(p, TYPE_PARAM_LIST);
}
fn lifetime_param(p: &mut Parser) {
assert!(p.at(LIFETIME));
let m = p.start();
fn lifetime_param(p: &mut Parser) {
assert!(p.at(LIFETIME));
let m = p.start();
p.bump();
if p.at(COLON) {
lifetime_bounds(p);
}
m.complete(p, LIFETIME_PARAM);
}
fn type_param(p: &mut Parser) {
assert!(p.at(IDENT));
let m = p.start();
name(p);
if p.at(COLON) {
bounds(p);
}
// test type_param_default
// struct S<T = i32>;
if p.at(EQ) {
p.bump();
if p.at(COLON) {
lifetime_bounds(p);
}
m.complete(p, LIFETIME_PARAM);
}
fn type_param(p: &mut Parser) {
assert!(p.at(IDENT));
let m = p.start();
name(p);
if p.at(COLON) {
bounds(p);
}
// test type_param_default
// struct S<T = i32>;
if p.at(EQ) {
p.bump();
types::type_(p)
}
m.complete(p, TYPE_PARAM);
types::type_(p)
}
m.complete(p, TYPE_PARAM);
}
// test type_param_bounds
@@ -99,7 +104,7 @@ pub(super) fn opt_where_clause(p: &mut Parser) {
let m = p.start();
p.bump();
loop {
if !(paths::is_path_start(p) || p.current() == LIFETIME) {
if !(paths::is_path_start(p) || p.current() == LIFETIME || p.current() == FOR_KW) {
break;
}
where_predicate(p);
@@ -112,19 +117,41 @@ pub(super) fn opt_where_clause(p: &mut Parser) {
fn where_predicate(p: &mut Parser) {
let m = p.start();
if p.at(LIFETIME) {
p.eat(LIFETIME);
if p.at(COLON) {
lifetime_bounds(p)
} else {
p.error("expected colon")
match p.current() {
LIFETIME => {
p.bump();
if p.at(COLON) {
lifetime_bounds(p);
} else {
p.error("expected colon");
}
}
} else {
types::path_type(p);
if p.at(COLON) {
bounds(p);
} else {
p.error("expected colon")
// test where_pred_for
// fn test<F>()
// where
// for<'a> F: Fn(&'a str)
// { }
FOR_KW => {
p.bump();
if p.at(L_ANGLE) {
type_param_list(p);
types::path_type(p);
if p.at(COLON) {
bounds(p);
} else {
p.error("expected colon");
}
} else {
p.error("expected `<`");
}
}
_ => {
types::path_type(p);
if p.at(COLON) {
bounds(p);
} else {
p.error("expected colon");
}
}
}
m.complete(p, WHERE_PRED);