rust/src/grammar/mod.rs
2018-08-08 22:15:14 +03:00

161 lines
3.8 KiB
Rust

//! 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:
//!
//! ```
//! // test fn_item_with_zero_parameters
//! // 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.
mod attributes;
mod expressions;
mod items;
mod params;
mod paths;
mod patterns;
mod type_args;
mod type_params;
mod types;
use {
parser_api::{CompletedMarker, Parser, TokenSet},
SyntaxKind::{self, *},
};
pub(crate) fn file(p: &mut Parser) {
let file = p.start();
p.eat(SHEBANG);
items::mod_contents(p, false);
file.complete(p, FILE);
}
#[derive(Clone, Copy, PartialEq, Eq)]
enum BlockLike {
Block,
NotBlock,
}
impl BlockLike {
fn is_block(self) -> bool { self == BlockLike::Block }
}
fn visibility(p: &mut Parser) {
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);
}
_ => (),
}
}
m.complete(p, VISIBILITY);
}
// test crate_keyword_vis
// crate fn main() { }
CRATE_KW => {
let m = p.start();
p.bump();
m.complete(p, VISIBILITY);
}
_ => (),
}
}
fn alias(p: &mut Parser) -> bool {
if p.at(AS_KW) {
let alias = p.start();
p.bump();
name(p);
alias.complete(p, ALIAS);
}
true //FIXME: return false if three are errors
}
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);
}
fn fn_ret_type(p: &mut Parser) -> bool {
if p.at(THIN_ARROW) {
p.bump();
types::type_(p);
true
} else {
false
}
}
fn name(p: &mut Parser) {
if p.at(IDENT) {
let m = p.start();
p.bump();
m.complete(p, NAME);
} else {
p.error("expected a name");
}
}
fn name_ref(p: &mut Parser) {
if p.at(IDENT) {
let m = p.start();
p.bump();
m.complete(p, NAME_REF);
} else {
p.error("expected identifier");
}
}
fn error_block(p: &mut Parser, message: &str) {
assert!(p.at(L_CURLY));
let err = p.start();
p.error(message);
p.bump();
let mut level: u32 = 1;
while level > 0 && !p.at(EOF) {
match p.current() {
L_CURLY => level += 1,
R_CURLY => level -= 1,
_ => (),
}
p.bump();
}
err.complete(p, ERROR);
}