rust/crates/parser/src/grammar/generic_args.rs
2021-09-19 16:35:10 +03:00

120 lines
3.4 KiB
Rust

use super::*;
pub(super) fn opt_generic_arg_list(p: &mut Parser, colon_colon_required: bool) {
let m;
if p.at(T![::]) && p.nth(2) == T![<] {
m = p.start();
p.bump(T![::]);
p.bump(T![<]);
} else if !colon_colon_required && p.at(T![<]) && p.nth(1) != T![=] {
m = p.start();
p.bump(T![<]);
} else {
return;
}
while !p.at(EOF) && !p.at(T![>]) {
generic_arg(p);
if !p.at(T![>]) && !p.expect(T![,]) {
break;
}
}
p.expect(T![>]);
m.complete(p, GENERIC_ARG_LIST);
}
// test generic_arg
// type T = S<i32>;
fn generic_arg(p: &mut Parser) {
match p.current() {
LIFETIME_IDENT => lifetime_arg(p),
T!['{'] | T![true] | T![false] | T![-] => const_arg(p),
k if k.is_literal() => const_arg(p),
// test associated_type_bounds
// fn print_all<T: Iterator<Item, Item::Item, Item::<true>, Item: Display, Item<'a> = Item>>(printables: T) {}
IDENT if [T![<], T![=], T![:]].contains(&p.nth(1)) => {
let m = p.start();
name_ref(p);
opt_generic_arg_list(p, false);
match p.current() {
// test assoc_type_eq
// type T = StreamingIterator<Item<'a> = &'a T>;
T![=] => {
p.bump_any();
types::type_(p);
m.complete(p, ASSOC_TYPE_ARG);
}
// test assoc_type_bound
// type T = StreamingIterator<Item<'a>: Clone>;
T![:] if !p.at(T![::]) => {
generic_params::bounds(p);
m.complete(p, ASSOC_TYPE_ARG);
}
_ => {
let m = m.complete(p, PATH_SEGMENT).precede(p).complete(p, PATH);
let m = paths::type_path_for_qualifier(p, m);
m.precede(p).complete(p, PATH_TYPE).precede(p).complete(p, TYPE_ARG);
}
}
}
_ => type_arg(p),
}
}
// test lifetime_arg
// type T = S<'static>;
fn lifetime_arg(p: &mut Parser) {
let m = p.start();
lifetime(p);
m.complete(p, LIFETIME_ARG);
}
// test const_arg
// type T = S<92>;
pub(super) fn const_arg(p: &mut Parser) {
let m = p.start();
match p.current() {
// test const_arg_block
// type T = S<{90 + 2}>;
T!['{'] => {
expressions::block_expr(p);
m.complete(p, CONST_ARG);
}
// test const_arg_literal
// type T = S<"hello", 0xdeadbeef>;
k if k.is_literal() => {
expressions::literal(p);
m.complete(p, CONST_ARG);
}
// test const_arg_bool_literal
// type T = S<true>;
T![true] | T![false] => {
expressions::literal(p);
m.complete(p, CONST_ARG);
}
// test const_arg_negative_number
// type T = S<-92>;
T![-] => {
let lm = p.start();
p.bump(T![-]);
expressions::literal(p);
lm.complete(p, PREFIX_EXPR);
m.complete(p, CONST_ARG);
}
// test const_arg_path
// struct S<const N: u32 = u32::MAX>;
_ => {
let lm = p.start();
paths::use_path(p);
lm.complete(p, PATH_EXPR);
m.complete(p, CONST_ARG);
}
}
}
fn type_arg(p: &mut Parser) {
let m = p.start();
types::type_(p);
m.complete(p, TYPE_ARG);
}