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( 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(p: &mut Parser, node_kind: SyntaxKind, rest: F) { p.start(node_kind); rest(p); p.finish(); } fn many 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 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(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(); } }