expect.lisp

(asdf:oos 'asdf:load-op :cl-ppcre)
(defpackage expect
  (:use :cl :cl-ppcre)
  (:export expect expect-strings))

(in-package expect)

(defmacro expect (port (&rest options) &body clauses)
  (let ((ch (gensym "ch"))
	(str (gensym "str"))
	(p (gensym "port"))
	(eof (gensym "eof"))
	(next (gensym "next")))
    `(let ((,p ,port)
	   (,str ""))
       (labels ((,next ()
		  (let ((,ch (read-char ,p nil ',eof)))
		    (unless (eq ',eof ,ch)
		      (setf ,str
			    (concatenate 'string ,str (string ,ch)))
		      (cond
			,@(mapcar
			   #'(lambda (clause)
			       `((funcall ,(car clause) ,str)
				 ,@(cdr clause)))
			   clauses)
			(T (,next)))))))
	 (,next)))))

(defmacro expect-strings (port (&rest options) &body clauses)
  (let ((syms (mapcar #'(lambda (_) (gensym)) clauses))
	(s (gensym)))
    `(let ,(mapcar
	     #'(lambda (clause sym)
		 `(,sym (lambda (,s)
			  (cl-ppcre:all-matches 
			   ,(car clause)
			   ,s))))
	     clauses
	     syms)
       (expect ,port (,@options)
	 ,@(mapcar
	    #'(lambda (clause sym)
		`(,sym ,@(cdr clause)))
	    clauses
	    syms)))))

;;
(with-input-from-string (s "Hello,World")
  (expect-strings s ()
    ("Foo" (print 0))
    ("Hello" (print 1))
    ("World" (print 2))))