doc/runtime.tex: Demote the object-system support stuff to a section.

[sod] / src / module-parse.lisp

;;; -*-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' id ( `,' id )* `;'
  (declare (ignore pset))
  (with-parser-context (token-scanner-context :scanner scanner)
    (parse (and "typename"
		(skip-many (:min 1)
		  (seq ((id :id))
		    (if (gethash id *module-type-map*)
			(cerror* "Type `~A' already defined" id)
			(add-to-module *module*
				       (make-instance 'type-item
						      :name id))))
		  #\,)
		#\;))))

;;; Fragments.

(define-pluggable-parser module code (scanner pset)
  ;; `code' id `:' item-name [constraints] `{' c-fragment `}'
  ;;
  ;; constrains ::= `[' constraint-list `]'
  ;; 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 (kw))
		   #\:
		   (name (item))
		   (constraints (? (seq (#\[
					 (constraints (list (:min 1)
							(list (:min 1)
							  (item))
							#\,))
					 #\])
				     constraints)))
		   (fragment (parse-delimited-fragment scanner #\{ #\})))
	       (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))
	     (char-scanner (make-instance 'charbuf-scanner
					  :stream f-stream))
	     (scanner (make-instance 'sod-token-scanner
				     :char-scanner char-scanner)))
	(with-default-error-location (scanner)
	  (with-parser-context (token-scanner-context :scanner scanner)
	    (parse (skip-many ()
		     (seq ((pset (parse-property-set scanner))
			   (nil (error ()
				  (plug module scanner pset))))
		       (check-unused-properties pset))))))))))

(define-pluggable-parser module test (scanner pset)
  ;; `demo' string `;'
  (declare (ignore pset))
  (with-parser-context (token-scanner-context :scanner scanner)
    (parse (seq ("demo" (string :string) #\;)
	     (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)
	   (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 :string) #\;)
		   (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))))))
		 (seq ("load" (name :string) #\;)
		   (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' property-list `;'
  (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 0)
				 (error (:ignore-unconsumed t)
				   (parse-property scanner module-pset)
				   (skip-until (:keep-end t) #\, #\;))
				 #\,))))
		#\;))))

;;; 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)))
		 #\;)
	     (eval sexp)))))

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

(export 'class-item)

(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)
    (make-class-type name)
    (let* ((class (make-sod-class name (mapcar #'find-sod-class supers)
				  pset scanner))
	   (nick (sod-class-nickname class)))

      (labels ((parse-maybe-dotted-declarator (base-type)
		 ;; Parse a declarator or dotted-declarator, i.e., one whose
		 ;; centre is
		 ;;
		 ;; maybe-dotted-identifier ::= [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-declarator
		  scanner base-type
		  :kernel (parser ()
			    (seq ((name-a :id)
				  (name-b (? (seq (#\. (id :id)) id))))
			      (if name-b (cons name-a name-b)
				  name-a)))))

	       (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 #\{ #\}))))
			  (make-sod-method class sub-nick name type
					   body sub-pset scanner))))

	       (parse-initializer ()
		 ;; initializer ::= `=' c-fragment | `=' `{' c-fragment `}'
		 ;;
		 ;; Return (VALUE-KIND . VALUE-FORM), ready for passing to a
		 ;; `sod-initializer' constructor.

		 ;; This is kind of tricky because we have to juggle both
		 ;; layers of the parsing machinery.  The character scanner
		 ;; will already have consumed the lookahead token (which, if
		 ;; we're going to do anything, is `=').
		 (let ((char-scanner (token-scanner-char-scanner scanner)))

		   ;; First, skip the character-scanner past any whitespace.
		   ;; We don't record this consumption, which is a bit
		   ;; naughty, but nobody will actually mind.
		   (loop
		     (when (or (scanner-at-eof-p char-scanner)
			       (not (whitespace-char-p
				     (scanner-current-char char-scanner))))
		       (return))
		     (scanner-step char-scanner))

		   ;; Now maybe read an initializer.
		   (cond ((not (eql (token-type scanner) #\=))
			  ;; It's not an `=' after all.  There's no
			  ;; initializer.
			  (values '(#\=) nil nil))

			 ((and (not (scanner-at-eof-p char-scanner))
			       (char= (scanner-current-char char-scanner)
				      #\{))
			  ;; There's a brace after the `=', so we should
			  ;; consume the `=' here, and read a compound
			  ;; initializer enclosed in braces.
			  (parse (seq (#\= (frag (parse-delimited-fragment
						  scanner #\{ #\})))
				   (cons :compound frag))))

			 (t
			  ;; No brace, so read from the `=' up to, but not
			  ;; including, the trailing `,' or `;' delimiter.
			  (parse (seq ((frag (parse-delimited-fragment
					      scanner #\= '(#\; #\,)
					      :keep-end t)))
				   (cons :simple frag)))))))

	       (parse-slot-item (sub-pset base-type type name)
		 ;; slot-item ::=
		 ;;	declspec+ declarator -!- [initializer]
		 ;;		[`,' init-declarator-list] `;'
		 ;;
		 ;; init-declarator-list ::=
		 ;;	declarator [initializer] [`,' init-declarator-list]
		 (parse (and (seq ((init (? (parse-initializer))))
			       (make-sod-slot class name type
					      sub-pset scanner)
			       (when init
				 (make-sod-instance-initializer
				  class nick name (car init) (cdr init)
				  sub-pset scanner)))
			     (skip-many ()
			       (seq (#\,
				     (ds (parse-declarator scanner
							   base-type))
				     (init (? (parse-initializer))))
				 (make-sod-slot class (cdr ds) (car ds)
						sub-pset scanner)
				 (when init
				   (make-sod-instance-initializer
				    class nick (cdr ds)
				    (car init) (cdr init)
				    sub-pset scanner))))
			     #\;)))

	       (parse-initializer-item (sub-pset constructor)
		 ;; initializer-item ::=
		 ;;	[`class'] -!- slot-initializer-list `;'
		 ;;
		 ;; slot-initializer ::= id `.' id initializer
		 (parse (and (skip-many ()
			       (seq ((name-a :id) #\. (name-b :id)
				     (init (parse-initializer)))
				 (funcall constructor class
					  name-a name-b
					  (car init) (cdr init)
					  sub-pset scanner))
			       #\,)
			     #\;)))

	       (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*-with-location
			   scanner
			   "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
		 ;;
		 ;; 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 (class-item-dispatch sub-pset
							     ds
							     (car dc)
							     (cdr dc))))))
			    (and "class"
				 (parse-initializer-item
				  sub-pset
				  #'make-sod-class-initializer))
			    (parse-initializer-item
			     sub-pset
			     #'make-sod-instance-initializer)))))

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

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

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