diff options
| author | Boutade <thegoofist@protonmail.com> | 2019-04-27 08:12:29 -0500 |
|---|---|---|
| committer | Boutade <thegoofist@protonmail.com> | 2019-04-27 08:12:29 -0500 |
| commit | 1bed2e23644ca4514a2dfbca521f5841fa3507b2 (patch) | |
| tree | 2aec93fee7ed8c454637a30fab02d9ac8a59b3cc /parzival.lisp | |
| parent | 4db2291159831a93a35af68e8e176f4b51e220d5 (diff) | |
removed <~item<, changed semantics of <item<, added <peek<
Diffstat (limited to 'parzival.lisp')
| -rw-r--r-- | parzival.lisp | 18 |
1 files changed, 9 insertions, 9 deletions
diff --git a/parzival.lisp b/parzival.lisp index d17be0e..9dd9630 100644 --- a/parzival.lisp +++ b/parzival.lisp @@ -34,18 +34,18 @@ (lambda (stream) (values nil nil stream)) "Consumes nothing from input and fails the parse.") - -(<<def <item< - (lambda (stream) (values (read-char stream) t stream)) - "Consumes exactly one item from input and results in that item.") +(<<def <peek< + (lambda (stream) (values (peek-char nil stream nil nil) t stream)) + "A pseudo-parser that peeks at the next item without consuming it. Useful + for building efficient look-ahead of one item.") -(<<def <~item< +(<<def <item< (lambda (stream) (if (peek-char nil stream nil nil) - (funcall <item< stream) + (funcall (<<result (read-char stream)) stream) (funcall <fail< stream))) - "Results in next item from the input without consuming it.") + "Results in next item from the input stream, or fails.") (<<def <eof< @@ -171,9 +171,9 @@ is the result of PN." (defun <<~sat (pred) "(<<~SAT PRED) is like (<<SAT PRED) but doesn't consume the item if (FUNCALL PRED ITEM) is false." - (<<bind <~item< + (<<bind <peek< (lambda (c) (if (funcall pred c) - (<<result c) + <item< <fail<)))) |