src/pset-parse.lisp: Replace `dispatch' by some more elementary functions.

[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' 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* ((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 file (scanner pset)
  ;; `import' string `;'
  ;; `load' string `;'
  (declare (ignore pset))
  (flet ((common (name type what thunk)
           (when name
             (find-file (pathname (scanner-filename 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 path (module-files *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
                                 (progn
                                   (pushnew path (module-files *module*))
                                   (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 :location 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
                                                 :default init
                                                 :location 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))
           (superclasses
            (let ((superclasses (restart-case
                                    (mapcar #'find-sod-class
                                            (or supers (list "SodObject")))
                                  (continue ()
                                    (setf duff t)
                                    (list (find-sod-class "SodObject"))))))
              (find-duplicates (lambda (first second)
                                 (declare (ignore second))
                                 (setf duff t)
                                 (cerror* "Class `~A' has duplicate ~
                                           direct superclass `~A'"
                                          name first))
                               superclasses)
              (delete-duplicates superclasses)))
           (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 superclasses pset
                                  :location 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
                                                  :location 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
                                               :location 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
                                               :location scanner)
                                (when init
                                  (make-sod-instance-initializer
                                   class nick name init sub-pset
                                   :location 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
                                                    :location 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 --------------------------------------------------