-(flet ((dispatch (name args &rest spec)
- (acond ((find :invalid args :key #'car)
- (cons :invalid nil))
- ((find-if (lambda (item)
- (every (lambda (type arg)
- (eql type (car arg)))
- (cddr item)
- args))
- spec)
- (cons (car it) (apply (cadr it)
- (mapcar #'cdr args))))
- (t
- (cerror* "Type mismatch: operator `~A' applied to ~
- types ~{~(~A~)~#[~; and ~;, ~]~}"
- name
- (mapcar #'car args))
- (cons :invalid nil)))))
-
- (defun parse-expression (scanner)
- "Parse and evaluate a simple expression.