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Add look-ahead to parser object

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This commit is contained in:
Marijn Haverbeke
2011-07-25 17:02:49 +02:00
parent dca67f95cb
commit cce1b4667b
1 changed files with 48 additions and 34 deletions
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42
src/comp/syntax/parse/parser.rs
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@@ -36,6 +36,7 @@ type parser =
obj { obj {
fn peek() -> token::token; fn peek() -> token::token;
fn bump(); fn bump();
fn look_ahead(uint) -> token::token;
fn fatal(str) -> !; fn fatal(str) -> !;
fn warn(str); fn warn(str);
fn restrict(restriction); fn restrict(restriction);
@@ -46,6 +47,7 @@ type parser =
fn get_lo_pos() -> uint; fn get_lo_pos() -> uint;
fn get_hi_pos() -> uint; fn get_hi_pos() -> uint;
fn get_last_lo_pos() -> uint; fn get_last_lo_pos() -> uint;
fn get_last_hi_pos() -> uint;
fn get_prec_table() -> @op_spec[]; fn get_prec_table() -> @op_spec[];
fn get_str(token::str_num) -> str; fn get_str(token::str_num) -> str;
fn get_reader() -> lexer::reader; fn get_reader() -> lexer::reader;
@@ -77,23 +79,33 @@ fn new_parser(parse_sess sess, ast::crate_cfg cfg, lexer::reader rdr,
ast::crate_cfg cfg, ast::crate_cfg cfg,
file_type ftype, file_type ftype,
mutable token::token tok, mutable token::token tok,
mutable uint lo, mutable span tok_span,
mutable uint hi, mutable span last_tok_span,
mutable uint last_lo, mutable tup(token::token, span)[] buffer,
mutable restriction restr, mutable restriction restr,
lexer::reader rdr, lexer::reader rdr,
@op_spec[] precs, @op_spec[] precs,
hashmap[str, ()] bad_words) { hashmap[str, ()] bad_words) {
fn peek() -> token::token { ret tok; } fn peek() -> token::token { ret tok; }
fn bump() { fn bump() {
// log rdr.get_filename() last_tok_span = tok_span;
// + ":" + common::istr(lo.line as int); if ivec::len(buffer) == 0u {
last_lo = lo;
auto next = lexer::next_token(rdr); auto next = lexer::next_token(rdr);
tok = next._0; tok = next._0;
lo = next._1; tok_span = rec(lo=next._1, hi=rdr.get_chpos());
hi = rdr.get_chpos(); } else {
auto next = ivec::pop(buffer);
tok = next._0;
tok_span = next._1;
}
}
fn look_ahead(uint distance) -> token::token {
while ivec::len(buffer) < distance {
auto next = lexer::next_token(rdr);
buffer =
~[tup(next._0, rec(lo=next._1, hi=rdr.get_chpos()))] + buffer;
}
ret buffer.(distance-1u)._0;
} }
fn fatal(str m) -> ! { fn fatal(str m) -> ! {
codemap::emit_error(some(self.get_span()), m, sess.cm); codemap::emit_error(some(self.get_span()), m, sess.cm);
@@ -104,10 +116,11 @@ fn new_parser(parse_sess sess, ast::crate_cfg cfg, lexer::reader rdr,
} }
fn restrict(restriction r) { restr = r; } fn restrict(restriction r) { restr = r; }
fn get_restriction() -> restriction { ret restr; } fn get_restriction() -> restriction { ret restr; }
fn get_span() -> span { ret rec(lo=lo, hi=hi); } fn get_span() -> span { ret tok_span; }
fn get_lo_pos() -> uint { ret lo; } fn get_lo_pos() -> uint { ret tok_span.lo; }
fn get_hi_pos() -> uint { ret hi; } fn get_hi_pos() -> uint { ret tok_span.hi; }
fn get_last_lo_pos() -> uint { ret last_lo; } fn get_last_lo_pos() -> uint { ret last_tok_span.lo; }
fn get_last_hi_pos() -> uint { ret last_tok_span.hi; }
fn get_file_type() -> file_type { ret ftype; } fn get_file_type() -> file_type { ret ftype; }
fn get_cfg() -> ast::crate_cfg { ret cfg; } fn get_cfg() -> ast::crate_cfg { ret cfg; }
fn get_prec_table() -> @op_spec[] { ret precs; } fn get_prec_table() -> @op_spec[] { ret precs; }
@@ -124,8 +137,9 @@ fn new_parser(parse_sess sess, ast::crate_cfg cfg, lexer::reader rdr,
} }
auto tok0 = lexer::next_token(rdr); auto tok0 = lexer::next_token(rdr);
auto span0 = rec(lo=tok0._1, hi=rdr.get_chpos());
ret stdio_parser(sess, cfg, ftype, tok0._0, ret stdio_parser(sess, cfg, ftype, tok0._0,
tok0._1, tok0._1, tok0._1, UNRESTRICTED, rdr, span0, span0, ~[], UNRESTRICTED, rdr,
prec_table(), bad_expr_word_table()); prec_table(), bad_expr_word_table());
} }