;;; -*-lisp-*-
;;;
;;; Top-level parser for module syntax
;;;
;;; (c) 2010 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.

(in-package #:sod)

;;;--------------------------------------------------------------------------
;;; Toplevel syntax.

;;; Type names.

(define-pluggable-parser module typename (scanner pset)
  ;; `typename' list[id] `;'
  (declare (ignore pset))
  (with-parser-context (token-scanner-context :scanner scanner)
    (parse (and "typename"
		(skip-many ()
		  (error ()
		      (seq ((id :id))
			(if (or (gethash id *module-type-map*)
				(find-simple-c-type id))
			    (cerror* "Type `~A' already defined" id)
			    (add-to-module *module*
					   (make-instance 'type-item
							  :name id))))
		    (skip-until () #\, #\;))
		  #\,)
		(must #\;)))))

;;; Fragments.

(define-pluggable-parser module code (scanner pset)
  ;; `code' id `:' item-name [constraints] `{' c-fragment `}'
  ;;
  ;; constraints ::= `[' list[constraint] `]'
  ;; constraint ::= item-name+
  ;; item-name ::= id | `(' id+ `)'
  (declare (ignore pset))
  (with-parser-context (token-scanner-context :scanner scanner)
    (labels ((kw ()
	       (parse (seq ((kw :id))
			(intern (frob-identifier kw) 'keyword))))
	     (item ()
	       (parse (or (kw)
			  (seq (#\( (names (list (:min 1) (kw))) #\))
			    names)))))
      (parse (seq ("code"
		   (reason (must (kw)))
		   (nil (must #\:))
		   (name (must (item)))
		   (constraints (? (seq (#\[
					 (constraints
					  (list ()
					    (list (:min 1)
					      (error (:ignore-unconsumed t)
						  (item)
						(skip-until ()
						  :id #\( #\, #\])))
					    #\,))
					 #\])
				     constraints)))
		   (fragment (parse-delimited-fragment scanner #\{ #\})))
	       (when name
		 (add-to-module *module*
				(make-instance 'code-fragment-item
					       :fragment fragment
					       :constraints constraints
					       :reason reason
					       :name name))))))))

;;; External files.

(export 'read-module)
(defun read-module (pathname &key (truename nil truep) location)
  "Parse the file at PATHNAME as a module, returning it.

   This is the main entry point for parsing module files.  You may well know
   the file's TRUENAME already (e.g., because `probe-file' dropped it into
   your lap) so you can avoid repeating the search by providing it.

   The LOCATION is the thing which wanted the module imported -- usually a
   `file-location' object, though it might be anything other than `t' which
   can be printed in the event of circular imports."

  (setf pathname (merge-pathnames pathname
				  (make-pathname :type "SOD" :case :common)))
  (unless truep (setf truename (truename pathname)))
  (define-module (pathname :location location :truename truename)
    (with-open-file (f-stream pathname :direction :input)
      (let* ((*readtable* (copy-readtable))
	     (*package* (find-package '#:sod-user))
	     (char-scanner (make-instance 'charbuf-scanner
					  :stream f-stream
					  :filename (namestring pathname)))
	     (scanner (make-instance 'sod-token-scanner
				     :char-scanner char-scanner)))
	(with-default-error-location (scanner)
	  (with-parser-context (token-scanner-context :scanner scanner)
	    (multiple-value-bind (result winp consumedp)
		(parse (skip-many ()
			  (seq ((pset (parse-property-set scanner))
				(nil (error ()
					 (plug module scanner pset)
				       (skip-until (:keep-end nil)
					 #\; #\}))))
			    (check-unused-properties pset))))
	      (declare (ignore consumedp))
	      (unless winp (syntax-error scanner result)))))))))

(define-pluggable-parser module test (scanner pset)
  ;; `demo' string `;'
  (declare (ignore pset))
  (with-parser-context (token-scanner-context :scanner scanner)
    (parse (seq ("demo" (string (must :string)) (nil (must #\;)))
	     (format t ";; DEMO ~S~%" string)))))

(define-pluggable-parser module file (scanner pset)
  ;; `import' string `;'
  ;; `load' string `;'
  (declare (ignore pset))
  (flet ((common (name type what thunk)
	   (when name
	     (find-file scanner
			(merge-pathnames name
					 (make-pathname :type type
							:case :common))
			what
			thunk))))
    (with-parser-context (token-scanner-context :scanner scanner)
      (parse (or (seq ("import" (name (must :string)) (nil (must #\;)))
		   (common name "SOD" "module"
			   (lambda (path true)
			     (handler-case
				 (let ((module (read-module path
							    :truename true)))
				   (when module
				     (module-import module)
				     (pushnew module
					      (module-dependencies
					       *module*))))
			       (file-error (error)
				 (cerror* "Error reading module ~S: ~A"
					  path error))
			       (error (error)
				 (cerror* "Unexpected error reading ~
					   module ~S: ~A"
					  path error))))))
		 (seq ("load" (name (must :string)) (nil (must #\;)))
		   (common name "LISP" "Lisp file"
			   (lambda (path true)
			     (handler-case
				 (load true :verbose nil :print nil)
			       (error (error)
				 (cerror* "Error loading Lisp file ~S: ~A"
					  path error)))))))))))

;;; Setting properties.

(define-pluggable-parser module set (scanner pset)
  ;; `set' list[property] `;'
  (with-parser-context (token-scanner-context :scanner scanner)
    (parse (and "set"
		(lisp (let ((module-pset (module-pset *module*)))
			(when pset
			  (pset-map (lambda (prop)
				      (add-property
				       module-pset
				       (p-name prop) (p-value prop)
				       :type (p-type prop)
				       :location (p-location prop))
				      (setf (p-seenp prop) t))
				    pset))
			(parse (skip-many (:min (if pset 0 1))
				 (error (:ignore-unconsumed t)
				     (parse-property scanner module-pset)
				   (skip-until () #\, #\;))
				 #\,))))
		#\;))))

;;; Lisp escape.

(define-pluggable-parser module lisp (scanner pset)
  ;; `lisp' s-expression `;'
  (declare (ignore pset))
  (with-parser-context (token-scanner-context :scanner scanner)
    (parse (seq ((sexp (if (and (eql (token-type scanner) :id)
				(string= (token-value scanner) "lisp"))
			   (let* ((stream (make-scanner-stream scanner))
				  (sexp (read stream t)))
			     (scanner-step scanner)
			     (values sexp t t))
			   (values '((:id "lisp")) nil nil)))
		 (nil (must #\;)))
	     (eval sexp)))))

;;;--------------------------------------------------------------------------
;;; Class declarations.

(export 'class-item)

(define-pluggable-parser class-item initfrags (scanner class pset)
  ;; raw-class-item ::= frag-keyword `{' c-fragment `}'
  ;; frag-keyword ::= `init' | `teardown'
  (with-parser-context (token-scanner-context :scanner scanner)
    (parse (seq ((make (or (seq ("init") #'make-sod-class-initfrag)
			   (seq ("teardown") #'make-sod-class-tearfrag)))
		 (frag (parse-delimited-fragment scanner #\{ #\})))
	     (funcall make class frag pset scanner)))))

(define-pluggable-parser class-item initargs (scanner class pset)
  ;; initarg-item ::= `initarg' declspec+ list[init-declarator]
  ;; init-declarator ::= declarator [`=' initializer]
  (with-parser-context (token-scanner-context :scanner scanner)
    (parse (seq ("initarg"
		 (base-type (parse-c-type scanner))
		 (nil (skip-many (:min 1)
			(seq ((declarator (parse-declarator scanner
							    base-type))
			      (init (? (parse-delimited-fragment
					scanner #\= (list #\; #\,)
					:keep-end t))))
			  (make-sod-user-initarg class
						 (cdr declarator)
						 (car declarator)
						 pset init scanner))
			#\,))
		 (nil (must #\;)))))))

(defun synthetic-name ()
  "Return an obviously bogus synthetic not-identifier."
  (let ((ix *temporary-index*))
    (incf *temporary-index*)
    (make-instance 'temporary-variable :tag (format nil "%%#~A" ix))))

(defun parse-class-body (scanner pset name supers)
  ;; class-body ::= `{' class-item* `}'
  ;;
  ;; class-item ::= property-set raw-class-item
  (with-parser-context (token-scanner-context :scanner scanner)
    (when name (make-class-type name))
    (let* ((duff (null name))
	   (synthetic-name (or name
			       (let ((var (synthetic-name)))
				 (unless pset
				   (setf pset (make-property-set)))
				 (unless (pset-get pset "nick")
				   (add-property pset "nick" var :type :id))
				 var)))
	   (class (make-sod-class synthetic-name
				  (restart-case
				      (mapcar #'find-sod-class
					      (or supers (list "SodObject")))
				    (continue ()
				      (setf duff t)
				      (list (find-sod-class "SodObject"))))
				  pset scanner))
	   (nick (sod-class-nickname class)))

      (labels ((must-id ()
		 (parse (must :id (progn (setf duff t) (synthetic-name)))))

	       (parse-maybe-dotted-name ()
		 ;; maybe-dotted-name ::= [id `.'] id
		 ;;
		 ;; A plain identifier is returned as a string, as usual; a
		 ;; dotted identifier is returned as a cons cell of the two
		 ;; names.
		 (parse (seq ((name-a (must-id))
			      (name-b (? (seq (#\. (id (must-id))) id))))
			  (if name-b (cons name-a name-b)
			      name-a))))

	       (parse-maybe-dotted-declarator (base-type)
		 ;; Parse a declarator or dotted-declarator, i.e., one whose
		 ;; centre is maybe-dotted-name above.
		 (parse-declarator scanner base-type
				   :keywordp t
				   :kernel #'parse-maybe-dotted-name))

	       (parse-message-item (sub-pset type name)
		 ;; message-item ::=
		 ;;	declspec+ declarator -!- (method-body | `;')
		 ;;
		 ;; Don't allow a method-body here if the message takes a
		 ;; varargs list, because we don't have a name for the
		 ;; `va_list' parameter.
		 (let ((message (make-sod-message class name type
						  sub-pset scanner)))
		   (if (varargs-message-p message)
		       (parse #\;)
		       (parse (or #\; (parse-method-item sub-pset
							 type nick name))))))

	       (parse-method-item (sub-pset type sub-nick name)
		 ;; method-item ::=
		 ;;	declspec+ dotted-declarator -!- method-body
		 ;;
		 ;; method-body ::= `{' c-fragment `}' | `extern' `;'
		 (parse (seq ((body (or (seq ("extern" #\;) nil)
					(parse-delimited-fragment
					 scanner #\{ #\}))))
			  (restart-case
			      (make-sod-method class sub-nick name type
					       body sub-pset scanner)
			    (continue () :report "Continue")))))

	       (parse-initializer ()
		 ;; initializer ::= `=' c-fragment
		 ;;
		 ;; Return a VALUE, ready for passing to a `sod-initializer'
		 ;; constructor.
		 (parse-delimited-fragment scanner #\= '(#\, #\;)
					   :keep-end t))

	       (parse-slot-item (sub-pset base-type type name)
		 ;; slot-item ::=
		 ;;	declspec+ declarator -!- [initializer]
		 ;;		[`,' list[init-declarator]] `;'
		 ;;
		 ;; init-declarator ::=	declarator [initializer]
		 (flet ((make-it (name type init)
			  (restart-case
			      (progn
				(make-sod-slot class name type
					       sub-pset scanner)
				(when init
				  (make-sod-instance-initializer class
								 nick name
								 init
								 sub-pset
								 scanner)))
			    (continue () :report "Continue"))))
		   (parse (and (error ()
				   (seq ((init (? (parse-initializer))))
				     (make-it name type init))
				 (skip-until () #\, #\;))
			       (skip-many ()
				 (error (:ignore-unconsumed t)
				     (seq (#\,
					   (ds (parse-declarator scanner
								 base-type))
					   (init (? (parse-initializer))))
				       (make-it (cdr ds) (car ds) init))
				   (skip-until () #\, #\;)))
			       (must #\;)))))

	       (parse-initializer-item (sub-pset must-init-p constructor)
		 ;; initializer-item ::=
		 ;;	[`class'] -!- list[slot-initializer] `;'
		 ;;
		 ;; slot-initializer ::= id `.' id [initializer]
		 (let ((parse-init (if must-init-p #'parse-initializer
				       (parser () (? (parse-initializer))))))
		   (parse (and (skip-many ()
				 (error (:ignore-unconsumed t)
				     (seq ((name-a :id) #\.
					   (name-b (must-id))
					   (init (funcall parse-init)))
				       (restart-case
					   (funcall constructor class
						    name-a name-b init
						    sub-pset scanner)
					 (continue () :report "Continue")))
				   (skip-until () #\, #\;))
				 #\,)
			       (must #\;)))))

	       (class-item-dispatch (sub-pset base-type type name)
		 ;; Logically part of `parse-raw-class-item', but the
		 ;; indentation was getting crazy.  We're currently at
		 ;;
		 ;; raw-class-item ::=
		 ;;	declspec+ (declarator | dotted-declarator) -!- ...
		 ;;   | other-items
		 ;;
		 ;; If the declarator is dotted then this must be a method
		 ;; definition; otherwise it might be a message or slot.
		 (cond ((not (typep type 'c-function-type))
			(when (consp name)
			  (cerror*
			   "Method declarations must have function type")
			  (setf name (cdr name)))
			(parse-slot-item sub-pset base-type type name))
		       ((consp name)
			(parse-method-item sub-pset type
					   (car name) (cdr name)))
		       (t
			(parse-message-item sub-pset type name))))

	       (parse-raw-class-item (sub-pset)
		 ;; raw-class-item ::=
		 ;;	message-item
		 ;;   | method-item
		 ;;   | slot-item
		 ;;   | initializer-item
		 ;;   | initfrag-item
		 ;;
		 ;; Most of the above begin with declspecs and a declarator
		 ;; (which might be dotted).  So we parse that here and
		 ;; dispatch based on what we find.
		 (parse (or (plug class-item scanner class sub-pset)
			    (peek
			     (seq ((ds (parse-c-type scanner))
				   (dc (parse-maybe-dotted-declarator ds))
				   (nil (commit))
				   (nil (class-item-dispatch sub-pset
							     ds
							     (car dc)
							     (cdr dc))))))
			    (and "class"
				 (parse-initializer-item sub-pset t
				  #'make-sod-class-initializer))
			    (parse-initializer-item sub-pset nil
			     #'make-sod-instance-initializer)))))

	(parse (seq ((nil (must #\{))
		     (nil (skip-many ()
			    (seq ((sub-pset (parse-property-set scanner))
				  (nil (parse-raw-class-item sub-pset)))
			      (check-unused-properties sub-pset))))
		     (nil (must #\})))
		 (unless (finalize-sod-class class)
		   (setf duff t))
		 (unless duff
		   (add-to-module *module* class))))))))

(define-pluggable-parser module class (scanner pset)
  ;; `class' id `:' list[id] class-body
  ;; `class' id `;'
  (with-parser-context (token-scanner-context :scanner scanner)
    (parse (seq ("class"
		 (name (must :id))
		 (nil (or (seq (#\;)
			    (when name (make-class-type name)))
			  (seq ((supers (must (seq (#\:
						    (ids (list () :id #\,)))
						ids)))
				(nil (parse-class-body
				      scanner
				      pset name supers)))))))))))

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