bjoernager/rust
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Add new syntax for interpolation and repetition, and allow the transcription of separators.

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This commit is contained in:
Paul Stansifer 2012-07-05 14:30:56 -07:00
parent 62db5706e6
commit 7f9b1fbe35
4 changed files with 70 additions and 39 deletions
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75
src/libsyntax/parse/parser.rs
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@ -1130,6 +1130,26 @@ class parser {
ret e;
}
fn parse_sep_and_zerok() -> (option<token::token>, bool) {
if self.token == token::BINOP(token::STAR)
|| self.token == token::BINOP(token::PLUS) {
let zerok = self.token == token::BINOP(token::STAR);
self.bump();
ret (none, zerok);
} else {
let sep = self.token;
self.bump();
if self.token == token::BINOP(token::STAR)
|| self.token == token::BINOP(token::PLUS) {
let zerok = self.token == token::BINOP(token::STAR);
self.bump();
ret (some(sep), zerok);
} else {
self.fatal("expected '*' or '+'");
}
}
}
fn parse_token_tree() -> token_tree {
/// what's the opposite delimiter?
fn flip(&t: token::token) -> token::token {
@ -1142,12 +1162,6 @@ class parser {
}
fn parse_tt_flat(p: parser, delim_ok: bool) -> token_tree {
if p.eat_keyword("many") && p.quote_depth > 0u {
let seq = p.parse_seq(token::LPAREN, token::RPAREN,
seq_sep_none(),
|p| p.parse_token_tree());
ret tt_dotdotdot(seq.span, seq.node);
}
alt p.token {
token::RPAREN | token::RBRACE | token::RBRACKET
if !delim_ok {
@ -1161,7 +1175,16 @@ class parser {
token::DOLLAR if p.quote_depth > 0u {
p.bump();
let sp = p.span;
ret tt_interpolate(sp, p.parse_ident());
if p.token == token::LPAREN {
let seq = p.parse_seq(token::LPAREN, token::RPAREN,
seq_sep_none(),
|p| p.parse_token_tree());
let (s, z) = p.parse_sep_and_zerok();
ret tt_dotdotdot(mk_sp(sp.lo ,p.span.hi), seq.node, s, z);
} else {
ret tt_interpolate(sp, p.parse_ident());
}
}
_ { /* ok */ }
}
@ -1221,34 +1244,32 @@ class parser {
fn parse_matcher(name_idx: @mut uint) -> matcher {
let lo = self.span.lo;
let mut sep = none;
if self.eat_keyword("sep") { sep = some(self.token); self.bump(); }
let m = if self.is_keyword("many")||self.is_keyword("at_least_one") {
let zero_ok = self.is_keyword("many");
let m = if self.token == token::DOLLAR {
self.bump();
let ms = (self.parse_seq(token::LPAREN, token::RPAREN,
common::seq_sep_none(),
|p| p.parse_matcher(name_idx)).node);
if ms.len() == 0u {
self.fatal("repetition body must be nonempty");
if self.token == token::LPAREN {
let ms = (self.parse_seq(token::LPAREN, token::RPAREN,
common::seq_sep_none(),
|p| p.parse_matcher(name_idx)).node);
if ms.len() == 0u {
self.fatal("repetition body must be nonempty");
}
let (sep, zerok) = self.parse_sep_and_zerok();
mtc_rep(ms, sep, zerok)
} else {
let bound_to = self.parse_ident();
self.expect(token::COLON);
let nt_name = self.parse_ident();
let m = mtc_bb(bound_to, nt_name, *name_idx);
*name_idx += 1u;
m
}
mtc_rep(ms, sep, zero_ok)
} else if option::is_some(sep) {
self.fatal("`sep <tok>` must preceed `many` or `at_least_one`");
} else if self.eat_keyword("parse") {
let bound_to = self.parse_ident();
self.expect(token::EQ);
let nt_name = self.parse_ident();
let m = mtc_bb(bound_to, nt_name, *name_idx);
*name_idx += 1u;
m
} else {
let m = mtc_tok(self.token);
self.bump();
m
};
ret spanned(lo, self.span.hi, m);
}