Mercurial > public > mercurial-scm > hg-stable
comparison mercurial/parser.py @ 25816:43a8a87fc175
parser: resolve ambiguity where both prefix and primary actions are defined
If both actions are defined, a primary-expression action is accepted only if
the next token never starts new term. For example,
parsed as primary expression:
":" # next token 'end' has no action
"(:)" # next token ')' has no action
":+y" # next token '+' is infix operator
parsed as prefix operator:
":y" # next token 'y' is primary expression
":-y" # next token '-' is prefix operator
This is mostly the same resolution as the infix/suffix rules.
| author | Yuya Nishihara <yuya@tcha.org> |
|---|---|
| date | Sun, 05 Jul 2015 12:09:27 +0900 |
| parents | e71e5629e006 |
| children | 42ac9d1d1572 |
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| 25815:e71e5629e006 | 25816:43a8a87fc175 |
|---|---|
| 47 if m: | 47 if m: |
| 48 self._match(m) | 48 self._match(m) |
| 49 return expr | 49 return expr |
| 50 def _parse(self, bind=0): | 50 def _parse(self, bind=0): |
| 51 token, value, pos = self._advance() | 51 token, value, pos = self._advance() |
| 52 # handle prefix rules on current token | 52 # handle prefix rules on current token, take as primary if unambiguous |
| 53 primary, prefix = self._elements[token][1:3] | 53 primary, prefix = self._elements[token][1:3] |
| 54 if primary: | 54 if primary and not (prefix and self._hasnewterm()): |
| 55 expr = (primary, value) | 55 expr = (primary, value) |
| 56 elif prefix: | 56 elif prefix: |
| 57 expr = (prefix[0], self._parseoperand(*prefix[1:])) | 57 expr = (prefix[0], self._parseoperand(*prefix[1:])) |
| 58 else: | 58 else: |
| 59 raise error.ParseError(_("not a prefix: %s") % token, pos) | 59 raise error.ParseError(_("not a prefix: %s") % token, pos) |