(in-package #:monparser)

(declaim (ftype (function (parser string) result) parse))
(defun parse (parser data)
  (funcall parser
           (make-instance 'cursor :data data)
           (make-instance 'cursor :data data)))

(declaim (ftype (function (parser string) parser) append-on-failure))
(defun append-on-failure (p message)
  (lambda (start input)
    (let ((result (funcall p start input)))
      (if (failure-p result)
        (make-failure :place (failure-place result)
                      :message (concatenate 'string message (failure-message result))
                      :priority (failure-priority result))
        result))))

(defmacro defparser (name args parser)
  (let ((message (format nil "In ~a:~&" name)))
    (if (and (listp args) (every #'symbolp args))
      (let (definition)
        (when (= (length args) 0)
          (push `(defparameter ,name (,name)) definition))
        (push `(defun ,name (,@args) (append-on-failure ,parser ,message))
              definition)
        (push 'progn definition)
        definition)
      (error "Malformed argument list."))))