diff options
Diffstat (limited to 'parzival.lisp')
| -rw-r--r-- | parzival.lisp | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/parzival.lisp b/parzival.lisp index 4c47c32..7eaa611 100644 --- a/parzival.lisp +++ b/parzival.lisp @@ -152,6 +152,14 @@ in then. If the parse fails the combinator else is run instead." (<<and <item< #'rec)))))) #'rec)) +(defun <<filter (parser pred) + "Condition a successful parse on a predicate" + (<<bind parser + (lambda (parsed) + (if (funcall pred parsed) + (<<result parsed) + <fail<)))) + (defun <<or (&rest parsers) "Tries each parser one after the other, rewinding the input stream after each failure, and resulting in the first successful parse." @@ -425,6 +433,10 @@ the character C." (<<cons value-parser (<<* (<<and separator-parser value-parser)))) +(defun <<sep-by* (value-parser separator-parser) + "Just like <<SEP-BY, but matches an empty sequence" + (<<? (<<sep-by value-parser separator-parser))) + (defun <<brackets (left center right) (<<and left (<<bind center (lambda (bracketed-value) @@ -525,3 +537,4 @@ the character C." (defun returning (x) "Returns a lambda that returns x no matter what it gets as an argument" (lambda (ignore) x)) + |