103 lines
2.5 KiB
Rust
103 lines
2.5 KiB
Rust
use super::*;
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pub(super) const PATH_FIRST: TokenSet =
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token_set![IDENT, SELF_KW, SUPER_KW, CRATE_KW, COLONCOLON, L_ANGLE];
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pub(super) fn is_path_start(p: &Parser) -> bool {
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match p.current() {
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IDENT | SELF_KW | SUPER_KW | CRATE_KW | COLONCOLON => true,
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_ => false,
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}
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}
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pub(super) fn use_path(p: &mut Parser) {
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path(p, Mode::Use)
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}
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pub(super) fn type_path(p: &mut Parser) {
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path(p, Mode::Type)
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}
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pub(super) fn expr_path(p: &mut Parser) {
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path(p, Mode::Expr)
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}
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#[derive(Clone, Copy, Eq, PartialEq)]
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enum Mode {
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Use,
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Type,
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Expr,
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}
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fn path(p: &mut Parser, mode: Mode) {
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let path = p.start();
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path_segment(p, mode, true);
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let mut qual = path.complete(p, PATH);
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loop {
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let use_tree = match p.nth(1) {
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STAR | L_CURLY => true,
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_ => false,
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};
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if p.at(COLONCOLON) && !use_tree {
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let path = qual.precede(p);
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p.bump();
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path_segment(p, mode, false);
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let path = path.complete(p, PATH);
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qual = path;
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} else {
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break;
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}
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}
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}
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fn path_segment(p: &mut Parser, mode: Mode, first: bool) {
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let m = p.start();
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// test qual_paths
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// type X = <A as B>::Output;
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// fn foo() { <usize as Default>::default(); }
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if first && p.eat(L_ANGLE) {
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types::type_(p);
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if p.eat(AS_KW) {
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if is_path_start(p) {
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types::path_type(p);
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} else {
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p.error("expected a trait");
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}
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}
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p.expect(R_ANGLE);
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} else {
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if first {
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p.eat(COLONCOLON);
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}
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match p.current() {
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IDENT => {
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name_ref(p);
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opt_path_type_args(p, mode);
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}
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// test crate_path
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// use crate::foo;
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SELF_KW | SUPER_KW | CRATE_KW => p.bump(),
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_ => {
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p.err_recover("expected identifier", items::ITEM_RECOVERY_SET);
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}
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};
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}
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m.complete(p, PATH_SEGMENT);
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}
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fn opt_path_type_args(p: &mut Parser, mode: Mode) {
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match mode {
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Mode::Use => return,
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Mode::Type => {
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// test path_fn_trait_args
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// type F = Box<Fn(x: i32) -> ()>;
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if p.at(L_PAREN) {
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params::param_list_opt_patterns(p);
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opt_fn_ret_type(p);
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} else {
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type_args::opt_type_arg_list(p, false)
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}
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}
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Mode::Expr => type_args::opt_type_arg_list(p, true),
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}
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}
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