(in-package #:monparser)

(defun whitespace? (it)
  (or (char= it #\Space)
      (not (graphic-char-p it))))

(declaim (ftype (function (parser integer &optional integer) parser) repeat))
(defun repeat (p min &optional (max 0))
  (if (> min 0)
    (comp ((x p)
           (xs (repeat p (1- min) (1- max))))
      (cons x xs))
    (if (> max 0)
      (comp ((x (optional p))
             (xs (repeat p 0 (if x (1- max) 0))))
        (if x (cons x xs) x))
      nothing)))

(defmacro literal (word)
  (when (not (stringp word))
    (error "Literal only accepts strings as input."))
  (let ((binding-list '())
        (name-list '()))
    (loop :for c :across word :do
          (when c
            (let ((name (gensym)))
              (push name name-list)
              (push `(,name (unit ,c)) binding-list))))
    `(comp ,(reverse binding-list)
       ,(cons 'list (reverse name-list)))))

(declaim (ftype (function (parser parser &optional parser) parser) within))
(defun within (left p &optional right)
  (comp ((_ left)
         (cell p)
         (_ (or right left)))
    cell))

(declaim (ftype (function (parser parser) parser) interlinked))
(defun interlinked (p separator)
  (many (comp ((cell p)
               (_ (optional separator)))
          cell)))