rust/crates/ra_parser/src/grammar.rs

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//! This is the actual "grammar" of the Rust language.
//!
//! Each function in this module and its children corresponds
//! to a production of the format grammar. Submodules roughly
//! correspond to different *areas* of the grammar. By convention,
//! each submodule starts with `use super::*` import and exports
//! "public" productions via `pub(super)`.
//!
//! See docs for `Parser` to learn about API, available to the grammar,
//! and see docs for `Event` to learn how this actually manages to
//! produce parse trees.
//!
//! Code in this module also contains inline tests, which start with
//! `// test name-of-the-test` comment and look like this:
//!
//! ```
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//! // test function_with_zero_parameters
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//! // fn foo() {}
//! ```
//!
//! 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.
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mod attributes;
mod expressions;
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mod items;
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mod params;
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mod paths;
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mod patterns;
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mod type_args;
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mod type_params;
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mod types;
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use crate::{
SyntaxKind::{self, *},
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TokenSet,
parser::{CompletedMarker, Marker, Parser},
};
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pub(crate) fn root(p: &mut Parser) {
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let m = p.start();
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p.eat(SHEBANG);
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items::mod_contents(p, false);
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m.complete(p, SOURCE_FILE);
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}
pub(crate) fn macro_items(p: &mut Parser) {
let m = p.start();
items::mod_contents(p, false);
m.complete(p, MACRO_ITEMS);
}
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pub(crate) fn macro_stmts(p: &mut Parser) {
let m = p.start();
while !p.at(EOF) {
if p.current() == SEMI {
p.bump();
continue;
}
expressions::stmt(p, expressions::StmtWithSemi::Optional);
}
m.complete(p, MACRO_STMTS);
}
pub(crate) fn path(p: &mut Parser) {
paths::type_path(p);
}
pub(crate) fn expr(p: &mut Parser) {
expressions::expr(p);
}
pub(crate) fn type_(p: &mut Parser) {
types::type_(p)
}
pub(crate) fn pattern(p: &mut Parser) {
patterns::pattern(p)
}
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pub(crate) fn stmt(p: &mut Parser, with_semi: bool) {
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let with_semi = match with_semi {
true => expressions::StmtWithSemi::Yes,
false => expressions::StmtWithSemi::No,
};
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expressions::stmt(p, with_semi)
}
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pub(crate) fn item(p: &mut Parser) {
items::item_or_macro(p, true, items::ItemFlavor::Mod)
}
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pub(crate) fn reparser(
node: SyntaxKind,
first_child: Option<SyntaxKind>,
parent: Option<SyntaxKind>,
) -> Option<fn(&mut Parser)> {
let res = match node {
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BLOCK => expressions::block,
NAMED_FIELD_DEF_LIST => items::named_field_def_list,
NAMED_FIELD_LIST => items::named_field_list,
ENUM_VARIANT_LIST => items::enum_variant_list,
MATCH_ARM_LIST => items::match_arm_list,
USE_TREE_LIST => items::use_tree_list,
EXTERN_ITEM_LIST => items::extern_item_list,
TOKEN_TREE if first_child? == L_CURLY => items::token_tree,
ITEM_LIST => match parent? {
IMPL_BLOCK => items::impl_item_list,
TRAIT_DEF => items::trait_item_list,
MODULE => items::mod_item_list,
_ => return None,
},
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_ => return None,
};
Some(res)
}
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#[derive(Clone, Copy, PartialEq, Eq)]
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enum BlockLike {
Block,
NotBlock,
}
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impl BlockLike {
fn is_block(self) -> bool {
self == BlockLike::Block
}
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}
fn opt_visibility(p: &mut Parser) -> bool {
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match p.current() {
PUB_KW => {
let m = p.start();
p.bump();
if p.at(L_PAREN) {
match p.nth(1) {
// test crate_visibility
// pub(crate) struct S;
// pub(self) struct S;
// pub(self) struct S;
// pub(self) struct S;
CRATE_KW | SELF_KW | SUPER_KW => {
p.bump();
p.bump();
p.expect(R_PAREN);
}
IN_KW => {
p.bump();
p.bump();
paths::use_path(p);
p.expect(R_PAREN);
}
_ => (),
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}
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}
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m.complete(p, VISIBILITY);
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}
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// test crate_keyword_vis
// crate fn main() { }
// struct S { crate field: u32 }
// struct T(crate u32);
//
// test crate_keyword_path
// fn foo() { crate::foo(); }
CRATE_KW if p.nth(1) != COLONCOLON => {
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let m = p.start();
p.bump();
m.complete(p, VISIBILITY);
}
_ => return false,
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}
true
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}
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fn opt_alias(p: &mut Parser) {
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if p.at(AS_KW) {
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let m = p.start();
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p.bump();
if !p.eat(UNDERSCORE) {
name(p);
}
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m.complete(p, ALIAS);
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}
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}
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fn abi(p: &mut Parser) {
assert!(p.at(EXTERN_KW));
let abi = p.start();
p.bump();
match p.current() {
STRING | RAW_STRING => p.bump(),
_ => (),
}
abi.complete(p, ABI);
}
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fn opt_fn_ret_type(p: &mut Parser) -> bool {
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if p.at(THIN_ARROW) {
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let m = p.start();
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p.bump();
types::type_(p);
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m.complete(p, RET_TYPE);
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true
} else {
false
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}
}
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fn name_r(p: &mut Parser, recovery: TokenSet) {
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if p.at(IDENT) {
let m = p.start();
p.bump();
m.complete(p, NAME);
} else {
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p.err_recover("expected a name", recovery);
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}
}
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fn name(p: &mut Parser) {
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name_r(p, TokenSet::empty())
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}
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fn name_ref(p: &mut Parser) {
if p.at(IDENT) {
let m = p.start();
p.bump();
m.complete(p, NAME_REF);
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} else if p.at(SELF_KW) {
let m = p.start();
p.bump();
m.complete(p, SELF_KW);
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} else {
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p.err_and_bump("expected identifier");
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}
}
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fn error_block(p: &mut Parser, message: &str) {
assert!(p.at(L_CURLY));
let m = p.start();
p.error(message);
p.bump();
expressions::expr_block_contents(p);
p.eat(R_CURLY);
m.complete(p, ERROR);
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}