;;; -*-lisp-*-
;;;
;;; Test parser infrastructure
;;;
;;; (c) 2009 Straylight/Edgeware
;;;

;;;----- Licensing notice ---------------------------------------------------
;;;
;;; This file is part of the Sensible Object Design, an object system for C.
;;;
;;; SOD is free software; you can redistribute it and/or modify
;;; it under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 2 of the License, or
;;; (at your option) any later version.
;;;
;;; SOD is distributed in the hope that it will be useful,
;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with SOD; if not, write to the Free Software Foundation,
;;; Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

(cl:in-package #:sod-test)

(defclass test-parser (test-case)
  ())
(add-test *sod-test-suite* (get-suite test-parser))

;;;--------------------------------------------------------------------------
;;; Utilities.

(defmacro assert-parse
    ((string value winp consumedp &key (scanner (gensym "SCANNER-")))
     &body parser)
  (once-only (string value winp consumedp)
    (with-gensyms (my-value my-winp my-consumedp label what)
      `(let ((,scanner (make-string-scanner ,string)))
	 (declare (ignorable ,scanner))
	 (multiple-value-bind (,my-value ,my-winp ,my-consumedp)
	     (with-parser-context
		 (character-scanner-context :scanner ,scanner)
	       (parse ,@parser))
	   (flet ((,label (,what)
		    (format nil "~A; parsing ~S with ~S"
			    ,what ,string ',@parser)))
	     (cond (,winp
		    (assert-true ,my-winp (,label "winp"))
		    (if (eq ,value t)
			(assert-not-eql ,my-value nil
					(,label "parser result"))
			(assert-equal ,my-value ,value
				      (,label "parser result"))))
		   (t
		    (assert-false ,my-winp (,label "winp"))
		    (assert-true (and (null (set-difference ,my-value ,value
							    :test #'equal))
				      (null (set-difference ,value ,my-value
							    :test #'equal)))
				 (,label "failure indicator"))))
	     (if ,consumedp
		 (assert-true ,my-consumedp (,label "consumedp"))
		 (assert-false ,my-consumedp (,label "consumedp")))))))))

;;;--------------------------------------------------------------------------
;;; Simple parser tests.
;;;
;;; This lot causes SBCL to warn like a mad thing.  It's too clever for us,
;;; and does half of the work at compile time!

(def-test-method test-simple ((test test-parser) :run nil)
  "Test simple atomic parsers, because we rely on them later."

  ;; Characters match themselves.  For a character known only at run-time,
  ;; use (char CH).
  (assert-parse ("abcd" #\a t t) #\a)
  (let ((ch #\b))
    (assert-parse ("abcd" '(#\b) nil nil) (char ch)))

  ;; A character can't match at EOF.
  (assert-parse ("" '(#\z) nil nil) #\z)

  ;; All characters match :any; but EOF isn't a character.
  (assert-parse ("z" #\z t t) :any)
  (assert-parse ("" '(:any) nil nil) :any)

  ;; The parser (satisfies PREDICATE) succeeds if the PREDICATE returns
  ;; true when applied to the current character.
  (assert-parse ("a" #\a t t) (satisfies alpha-char-p))
  (assert-parse ("0" '(alpha-char-p) nil nil) (satisfies alpha-char-p))

  ;; The parser (not CHAR) matches a character other than CHAR; but it won't
  ;; match EOF.
  (assert-parse ("a" #\a t t) (not #\b))
  (assert-parse ("b" '((not #\b)) nil nil) (not #\b))
  (assert-parse ("" '((not #\b)) nil nil) (not #\b))

  ;; But :eof matches only at EOF.
  (assert-parse ("" :eof t nil) :eof)
  (assert-parse ("abcd" '(:eof) nil nil) :eof)

  ;; Strings match themselves without consuming if they fail.
  (assert-parse ("abcd" "ab" t t) "ab")
  (assert-parse ("abcd" '("cd") nil nil) "cd"))

(def-test-method test-sequence ((test test-parser) :run nil)

  ;; An empty sequence always succeeds and never consumes.  And provokes
  ;; warnings: don't do this.
  (assert-parse ("" :win t nil) (seq () :win))
  (assert-parse ("abcd" :win t nil) (seq () :win))

  ;; A `seq' matches the individual parsers in order, and binds their results
  ;; to variables -- if given.  The result is the value of the body.  If any
  ;; parser fails having consumed input, then input stays consumed.  There's
  ;; no backtracking.
  (assert-parse ("abcd" '(#\a . #\c) t t)
    (seq ((foo #\a) #\b (bar #\c)) (cons foo bar)))
  (assert-parse ("abcd" '(#\c) nil t)
    (seq ((foo #\a) (bar #\c)) (cons foo bar)))
  (assert-parse ("abcd" '(#\c) nil nil)
    (seq ((bar #\c) (foo #\a)) (cons foo bar))))

(def-test-method test-repeat ((test test-parser) :run nil)

  ;; A `many' matches a bunch of similar things in a row.  You can compute a
  ;; result using `do'-like accumulation.
  (assert-parse ("aaaab" 4 t t) (many (acc 0 (1+ acc)) #\a))

  ;; The default minimum is zero; so the parser always succeeds.
  (assert-parse ("aaaab" 0 t nil) (many (acc 0 (1+ acc)) #\b))

  ;; You can provide an explicit minimum.  Then the match might fail.
  (assert-parse ("aabb" 2 t t) (many (acc 0 (1+ acc) :min 2) #\a))
  (assert-parse ("aabb" '(#\a) nil t) (many (acc 0 (1+ acc) :min 3) #\a))

  ;; You can also provide an explicit maximum.  This will cause the parser to
  ;; stop searching, but it can't make it fail.
  (assert-parse ("aaaab" 3 t t) (many (acc 0 (1+ acc) :max 3) #\a))

  ;; You can provide both a maximum and a minimum at the same time.  If
  ;; they're consistent, you won't be surprised.  If they aren't, then the
  ;; maximum wins and the minimum is simply ignored (currently).
  (assert-parse ("aaaaab" 4 t t)
    (many (acc 0 (1+ acc) :min 3 :max 4) #\a))
  (assert-parse ("aabbbb" '(#\a) nil t)
    (many (acc 0 (1+ acc) :min 3 :max 4) #\a))
  (assert-parse ("aaabbb" 3 t t)
    (many (acc 0 (1+ acc) :min 3 :max 3) #\a))
  (assert-parse ("aaabbb" 3 t t)
    (many (acc 0 (1+ acc) :min 17 :max 3) #\a))

  ;; You can provide a separator.  The `many' parser will look for the
  ;; separator between each of the main items, but will ignore the results.
  (assert-parse ("a,a,abc" 3 t t) (many (acc 0 (1+ acc)) #\a #\,))
  (assert-parse ("a,a,abc" 2 t t) (many (acc 0 (1+ acc) :max 2) #\a #\,))

  ;; If `many' sees a separator then by default it commits to finding another
  ;; item; so this can cause a parse to fail.
  (assert-parse ("a,a,bc" '(#\a) nil t) (many (acc 0 (1+ acc)) #\a #\,))
  (assert-parse ("abc" 1 t t) (many (acc 0 (1+ acc)) #\a #\,))

  ;; If you specify a separator then the default minimum number of
  ;; repetitions becomes 1 rather than 0.  But you can override this
  ;; explicitly.
  (assert-parse ("bc" '(#\a) nil nil) (many (acc 0 (1+ acc)) #\a #\,))
  (assert-parse ("bc" 0 t nil) (many (acc 0 (1+ acc) :min 0) #\a #\,))

  ;; The parser will fail looking for a separator if there aren't enough
  ;; items.
  (assert-parse ("a,abc" '(#\,) nil t)
    (many (acc 0 (1+ acc) :min 3) #\a #\,))

  ;; You can override the commit-on-separator behaviour by using :commit.
  ;; This makes a trailing separator legal (but optional), so it also affects
  ;; the behaviour regarding maximum and minimum repetitions.  (Commitment is
  ;; irrelevant if you don't have a separator.)
  (assert-parse ("a,a,bc" 2 t t)
    (many (acc 0 (1+ acc) :commitp nil) #\a #\,))
  (assert-parse ("a,a,abc" 3 t t)
    (many (acc 0 (1+ acc) :commitp nil) #\a #\,))
  (assert-parse ("a,a,a,bc" 3 t t)
    (seq ((n (many (acc 0 (1+ acc) :max 3 :commitp t) #\a #\,))
	  #\,)
      n))
  (assert-parse ("a,a,a,bc" 3 t t)
    (seq ((n (many (acc 0 (1+ acc) :max 3 :commitp nil) #\a #\,))
	  #\b)
      n))
  (assert-parse ("a,a,bc" '(#\a) nil t)
    (many (acc 0 (1+ acc) :min 3 :commitp nil) #\a #\,))

  ;; The `many' parser won't backtrack.  The `many' eats as many `a's as
  ;; possible; asking for another one is sure to fail.
  (assert-parse ("aaaabc" '(#\a) nil t) (and (skip-many () #\a) #\a)))

(def-test-method test-repeat-hairy ((test test-parser) :run nil)
  ;; The `many' expander is very hairy and does magical things if it notices
  ;; that some of its arguments are constants.  So here we test a number of
  ;; the above things again, using variables so that it has to produce code
  ;; which makes decisions at run-time.  (I've no doubt that SBCL will issue
  ;; an infinite number of notes explaining how clever it is and how it can
  ;; do it all at compile-time anyway.  Of course, suppressing these notes is
  ;; the main reason `many' is so hairy anyway.)

  (let ((zero 0) (two 2) (three 3) (yes t) (no nil))

    ;; Minima.
    (assert-parse ("aaaab" 4 t t) (many (acc 0 (1+ acc) :min zero) #\a))
    (assert-parse ("aaaab" 0 t nil) (many (acc 0 (1+ acc) :min zero) #\b))
    (assert-parse ("aabb" 2 t t) (many (acc 0 (1+ acc) :min two) #\a))
    (assert-parse ("aabb" '(#\a) nil t)
      (many (acc 0 (1+ acc) :min three) #\a))

    ;; Maxima.
    (assert-parse ("aaaab" 4 t t) (many (acc 0 (1+ acc) :max no) #\a))
    (assert-parse ("aaaab" 3 t t) (many (acc 0 (1+ acc) :max three) #\a))

    ;; And now together with separators and commitment.  Oh, my.
    (assert-parse ("a,a,a,bc" 3 t t)
      (many (acc 0 (1+ acc) :commitp no) #\a #\,))
    (assert-parse ("a,a,a,bc" '(#\a) nil t)
      (many (acc 0 (1+ acc) :commitp yes) #\a #\,))
    (assert-parse ("a,a,bc" '(#\a) nil t)
      (many (acc 0 (1+ acc) :min three :commitp yes) #\a #\,))
    (assert-parse ("a,a,bc" '(#\a) nil t)
      (many (acc 0 (1+ acc) :min 3 :commitp yes) #\a #\,))
    (assert-parse ("a,a,bc" '(#\a) nil t)
      (many (acc 0 (1+ acc) :min three :commitp t) #\a #\,))
    (assert-parse ("a,a,a,bc" 3 t t)
      (seq ((n (many (acc 0 (1+ acc) :max three :commitp no) #\a #\,)) #\b)
	n))
    (assert-parse ("a,a,a,bc" 3 t t)
      (seq ((n (many (acc 0 (1+ acc) :max three :commitp yes) #\a #\,)) #\,)
	n))
    (assert-parse ("a,a,a,bc" 3 t t)
      (seq ((n (many (acc 0 (1+ acc) :max 3 :commitp no) #\a #\,)) #\b)
	n))
    (assert-parse ("a,a,a,bc" 3 t t)
      (seq ((n (many (acc 0 (1+ acc) :max 3 :commitp yes) #\a #\,)) #\,)
	n))
    (assert-parse ("a,a,a,bc" 3 t t)
      (seq ((n (many (acc 0 (1+ acc) :max three :commitp nil) #\a #\,)) #\b)
	n))
    (assert-parse ("a,a,a,bc" 3 t t)
      (seq ((n (many (acc 0 (1+ acc) :max three :commitp t) #\a #\,)) #\,)
	n))))

(def-test-method test-alternate ((test test-parser) :run nil)

  ;; An `or' matches the first parser that either succeeds or fails having
  ;; consumed input.
  (assert-parse ("abcd" #\a t t) (or #\a #\b))
  (assert-parse ("abcd" #\a t t) (or #\b #\a))
  (assert-parse ("abcd" '(#\b #\c) nil nil) (or #\b #\c))

  ;; Strings don't consume if they fail.
  (assert-parse ("abcd" "ab" t t) (or "cd" "ab"))
  (assert-parse ("abcd" "ab" t t) (or "ad" "ab"))
  (assert-parse ("abcd" '("ad" "ac") nil nil) (or "ad" "ac"))

  ;; But `seq' will if some component consumes.
  (assert-parse ("abcd" '(#\d) nil t) (or (and #\a #\d) "ab"))
  (assert-parse ("abcd" "ab" t t) (or (and #\c #\d) "ab"))

  ;; We can tame this using `peek' which rewinds the source if its argument
  ;; fails, so as to hide consumption of input.
  (assert-parse ("abcd" "ab" t t) (or (peek (and #\a #\d)) "ab"))
  (assert-parse ("abcd" '(#\a #\b "cd") t t)
    (seq ((foo (peek (seq ((foo #\a) (bar #\b)) (list foo bar))))
	  (bar "cd"))
      (append foo (list bar))))

  ;; Failure indicators are union'd if they all fail.
  (assert-parse ("abcd" '(#\q #\x #\z) nil nil)
    (or #\q (peek (and #\a (or #\x #\q))) #\z))

  ;; But if any of them consumed input then you only get the indicators from
  ;; the consuming branch, because we committed to it when we consumed the
  ;; input.
  (assert-parse ("abcd" '(#\x #\q) nil t)
    (or #\q #\z (and #\a (or #\q #\x)))))

;;;--------------------------------------------------------------------------
;;; Some tests with a simple recursive parser.

(defstruct (node
	     (:predicate nodep)
	     (:constructor make-node (left data right)))
  "Structure type for a simple binary tree."
  left data right)

(defun parse-tree (scanner)
  "Parse a textual representation into a simple binary tree.

   The syntax is simple:

	TREE ::= EMPTY | `(' TREE CHAR TREE `)'

   There's an ambiguity in this syntax, at least if you have limited
   lookahead: suppose you've just parsed the opening `(' of a TREE, and you
   see another `(' -- is it the start of the non-empty left sub-TREE, or is
   it the CHAR following an empty left sub-TREE?  We opt for the first choice
   always."

  ;; This came from another project, although it isn't actually used there.
  ;; It exposed the weakness in an earlier design which prompted the addition
  ;; of the CONSUMEDP flags to the parser protocol.

  (with-parser-context (character-scanner-context :scanner scanner)
    (labels ((tree ()
	       (parse (or (seq (#\(
				(left (tree))
				(data :any)
				(right (tree))
				#\))
			    (make-node left data right))
			  (values nil t nil)))))
      (parse (seq ((tree (tree)) :eof)
	       tree)))))

(defun parse-tree-lookahead (scanner)
  "Parse a textual representation into a simple binary tree.

   The syntax is simple, and, indeed, the grammar's the same as for
   `sod-parse-tree':

	TREE ::= EMPTY | `(' TREE CHAR TREE `)'

   But the rules are different.  Instead of resolving the `ambiguity' between
   TREE and CHAR when we find another `(' after the opening `(' of a TREE
   deterministically in favour of TREE as `parse-tree' does, we try that
   first, and backtrack if necessary."

  ;; Bison can do this, but you have to persuade it to use the scary GLR
  ;; parser algorithm

  (with-parser-context (character-scanner-context :scanner scanner)
    (labels ((tree ()
	       (parse (or (peek (seq (#\(
				      (left (tree))
				      (data :any)
				      (right (tree))
				      #\))
				  (make-node left data right)))
			  (values nil t nil)))))
      (parse (seq ((tree (tree)) :eof)
	       tree)))))

(def-test-method test-simple-tree-parser ((test test-parser) :run nil)
  (assert-parse ("" nil t nil :scanner sc) (parse-tree sc))
  (assert-parse ("((a)b((c)d(e)))" t t t :scanner sc) (parse-tree sc))
  (assert-parse ("((a)b((c)d(e)))z" '(:eof) nil t :scanner sc)
    (parse-tree sc))
  (assert-parse ("((a)b((c)d(e))" '(#\)) nil t :scanner sc) (parse-tree sc))
  (assert-parse ("(([)*(]))" t t t :scanner sc) (parse-tree sc))
  (assert-parse ("((()-()))" '(#\)) nil t :scanner sc) (parse-tree sc))
  (assert-parse ("((()-()))" t t t :scanner sc) (parse-tree-lookahead sc)))

;;;--------------------------------------------------------------------------
;;; Test expression parser.

(eval-when (:compile-toplevel :load-toplevel :execute)
  (defparse token (:context (context character-parser-context) parser)
    (with-gensyms (value)
      (expand-parser-spec context
			  `(seq ((,value ,parser) :whitespace) ,value)))))

(let ((add (binop "+" (x y 5) `(+ ,x ,y)))
      (sub (binop "-" (x y 5) `(- ,x ,y)))
      (mul (binop "*" (x y 7) `(* ,x ,y)))
      (div (binop "/" (x y 7) `(/ ,x ,y)))
      (eq (binop "=" (x y 3 :assoc nil) `(= ,x ,y)))
      (ne (binop "/=" (x y 3 :assoc nil) `(/= ,x ,y)))
      (lt (binop "<" (x y 3 :assoc nil) `(< ,x ,y)))
      (gt (binop ">" (x y 3 :assoc nil) `(> ,x ,y)))
      (and (binop "&" (x y 2) `(and ,x ,y)))
      (or (binop "|" (x y 1) `(or ,x ,y)))
      (expt (binop "**" (x y 8 :assoc :right) `(** ,x ,y)))
      (neg (preop "-" (x 9) `(- ,x)))
      (not (preop "!" (x 2) `(not ,x)))
      (fact (postop "!" (x 10) `(! ,x)))
      (lp (lparen #\))) (rp (rparen #\)))
      (lb (lparen #\])) (rb (rparen #\])))
  (defun test-parse-expr (string)
    (with-parser-context (string-parser :string string)
      (parse (seq (:whitespace
		   (value (expr (:nestedp nestedp)
			    (token (many (a 0 (+ (* a 10) it) :min 1)
				     (filter digit-char-p)))
			    (token (or (seq ("**") expt)
				       (seq ("/=") ne)
				       (seq (#\+) add)
				       (seq (#\-) sub)
				       (seq (#\*) mul)
				       (seq (#\/) div)
				       (seq (#\=) eq)
				       (seq (#\<) lt)
				       (seq (#\>) gt)
				       (seq (#\&) and)
				       (seq (#\|) or)))
			    (token (or (seq (#\() lp)
				       (seq (#\[) lb)
				       (seq (#\-) neg)
				       (seq (#\!) not)))
			    (token (or (seq (#\!) fact)
				       (when nestedp
					 (or (seq (#\)) rp)
					     (seq (#\]) rb)))))))
		   (next (or :any (t :eof))))
	       (cons value next))))))

(defun assert-expr-parse (string value winp consumedp)
  (multiple-value-bind (v w c) (test-parse-expr string)
    (flet ((message (what)
	     (format nil "expression ~S; ~A" string what)))
      (cond (winp (assert-true w (message "winp"))
		  (assert-equal v value (message "value")))
	    (t (assert-false w (message "winp"))
	       (assert-equal v value (message "expected"))))
      (assert-eql c consumedp (message "consumedp")))))

(def-test-method test-expression-parser ((test test-parser) :run nil)
  (assert-expr-parse "1 + 2 + 3" '((+ (+ 1 2) 3) . :eof) t t)
  (assert-expr-parse "1 + 2 * 3" '((+ 1 (* 2 3)) . :eof) t t)
  (assert-expr-parse "1 * 2 + 3" '((+ (* 1 2) 3) . :eof) t t)
  (assert-expr-parse "(1 + 2) * 3" '((* (+ 1 2) 3) . :eof) t t)
  (assert-expr-parse "1 ** 2 ** 3" '((** 1 (** 2 3)) . :eof) t t)
  (assert-expr-parse "1 + 2) * 3" '((+ 1 2) . #\)) t t)
  (assert-expr-parse "1 + 2 * 3" '((+ 1 (* 2 3)) . :eof) t t)
  (assert-expr-parse "! 1 + 2 = 3 | 6 - 3 /= 12/6"
		     '((or (not (= (+ 1 2) 3))
			   (/= (- 6 3) (/ 12 6)))
		       . :eof)
		     t t)
  (assert-expr-parse "! 1 > 2 & ! 4 < 6 | 3 < 4 & 9 > 10"
		     '((or (and (not (> 1 2)) (not (< 4 6)))
			   (and (< 3 4) (> 9 10)))
		       . :eof)
		     t t)

  (assert-condition 'simple-error (test-parse-expr "(1 + 2"))
  (assert-condition 'simple-error (test-parse-expr "(1 + 2]"))
  (assert-condition 'simple-error (test-parse-expr "1 < 2 < 3")))

;;;----- That's all, folks --------------------------------------------------