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|
use super::parser::Parser;
use {SyntaxKind};
use tree::EOF;
use syntax_kinds::*;
mod items;
mod attributes;
mod expressions;
mod paths;
pub(crate) fn file(p: &mut Parser) {
node(p, FILE, |p| {
p.eat(SHEBANG);
items::mod_contents(p);
})
}
fn visibility(p: &mut Parser) {
node_if(p, PUB_KW, VISIBILITY, |p| {
if p.current() != L_PAREN {
return
}
match p.raw_lookahead(1) {
CRATE_KW | SELF_KW | SUPER_KW => {
p.bump();
p.bump();
}
IN_KW => {
p.bump();
p.bump();
paths::use_path(p);
}
_ => return
}
p.expect(R_PAREN);
});
}
fn alias(p: &mut Parser) -> bool {
node_if(p, AS_KW, ALIAS, |p| {
p.expect(IDENT);
});
true //FIXME: return false if three are errors
}
fn node_if<F: FnOnce(&mut Parser), L: Lookahead>(
p: &mut Parser,
first: L,
node_kind: SyntaxKind,
rest: F
) -> bool {
first.is_ahead(p) && { node(p, node_kind, |p| { L::consume(p); rest(p); }); true }
}
fn node<F: FnOnce(&mut Parser)>(p: &mut Parser, node_kind: SyntaxKind, rest: F) {
p.start(node_kind);
rest(p);
p.finish();
}
fn many<F: FnMut(&mut Parser) -> bool>(p: &mut Parser, mut f: F) {
loop {
let pos = p.pos();
if !f(p) {
return
}
if pos == p.pos() {
panic!("Infinite loop in parser")
}
}
}
fn comma_list<F: Fn(&mut Parser) -> bool>(p: &mut Parser, end: SyntaxKind, f: F) {
many(p, |p| {
if !f(p) || p.current() == end {
false
} else {
p.expect(COMMA);
true
}
})
}
fn skip_to_first<C, F>(p: &mut Parser, cond: C, f: F, message: &str) -> bool
where
C: Fn(&Parser) -> bool,
F: FnOnce(&mut Parser),
{
let mut skipped = false;
loop {
if cond(p) {
if skipped {
p.finish();
}
f(p);
return true;
}
if p.current() == EOF {
if skipped {
p.finish();
}
return false;
}
if !skipped {
p.start(ERROR);
p.error()
.message(message)
.emit();
}
p.bump();
skipped = true;
}
}
impl<'p> Parser<'p> {
pub(crate) fn expect(&mut self, kind: SyntaxKind) -> bool {
if self.current() == kind {
self.bump();
true
} else {
self.error()
.message(format!("expected {:?}", kind))
.emit();
false
}
}
fn eat(&mut self, kind: SyntaxKind) -> bool {
self.current() == kind && { self.bump(); true }
}
}
trait Lookahead: Copy {
fn is_ahead(self, p: &Parser) -> bool;
fn consume(p: &mut Parser);
}
impl Lookahead for SyntaxKind {
fn is_ahead(self, p: &Parser) -> bool {
p.current() == self
}
fn consume(p: &mut Parser) {
p.bump();
}
}
impl Lookahead for [SyntaxKind; 2] {
fn is_ahead(self, p: &Parser) -> bool {
p.current() == self[0]
&& p.raw_lookahead(1) == self[1]
}
fn consume(p: &mut Parser) {
p.bump();
p.bump();
}
}
impl Lookahead for [SyntaxKind; 3] {
fn is_ahead(self, p: &Parser) -> bool {
p.current() == self[0]
&& p.raw_lookahead(1) == self[1]
&& p.raw_lookahead(2) == self[2]
}
fn consume(p: &mut Parser) {
p.bump();
p.bump();
p.bump();
}
}
#[derive(Clone, Copy)]
struct AnyOf<'a>(&'a [SyntaxKind]);
impl<'a> Lookahead for AnyOf<'a> {
fn is_ahead(self, p: &Parser) -> bool {
let curr = p.current();
self.0.iter().any(|&k| k == curr)
}
fn consume(p: &mut Parser) {
p.bump();
}
}
|
