src/ps-macrology.lisp

   1 (in-package :parenscript)
   2
   3 ;;;; The macrology of the Parenscript language.  Special forms and macros.
   4
   5 ;;; parenscript gensyms
   6 (defvar *gen-script-name-counter* 0)
   7
   8 (defun gen-script-name-string (&key (prefix "_js_"))
   9   "Generates a unique valid javascript identifier ()"
  10   (concatenate 'string
  11                prefix (princ-to-string (incf *gen-script-name-counter*))))
  12
  13 (defun gen-script-name (&key (prefix ""))
  14   "Generate a new javascript identifier."
  15   (intern (gen-script-name-string :prefix prefix)
  16           (find-package :parenscript.ps-gensyms)))
  17
  18 (defmacro gen-ps-name (&rest args)
  19   `(gen-script-name ,@args))
  20
  21 (defmacro with-unique-ps-names (symbols &body body)
  22   "Evaluate BODY with the variables on SYMBOLS bound to new javascript identifiers.
  23
  24 Each element of SYMBOLS is either a symbol or a list of (symbol
  25 prefix)."
  26   `(let* ,(mapcar (lambda (symbol)
  27                     (destructuring-bind (symbol &optional prefix)
  28                         (if (consp symbol)
  29                             symbol
  30                             (list symbol))
  31                       (if prefix
  32                           `(,symbol (gen-script-name :prefix ,prefix))
  33                           `(,symbol (gen-script-name)))))
  34                   symbols)
  35      ,@body))
  36
  37 (defvar *var-counter* 0)
  38
  39 (defun script-gensym (&optional (name "js"))
  40   (intern (format nil "tmp-~A-~A" name (incf *var-counter*)) #.*package*))
  41
  42 (defscriptmacro defaultf (place value)
  43   `(setf ,place (or (and (=== undefined ,place) ,place)
  44                  ,value)))
  45
  46 ;;; array literals
  47 (defscriptmacro list (&rest values)
  48   `(array ,@values))
  49
  50 (defscriptmacro make-array (&rest inits)
  51   `(new (*array ,@inits)))
  52
  53 ;;; eval-when
  54 (define-script-special-form eval-when (&rest args)
  55   "(eval-when form-language? (situation*) form*)
  56
  57 The given forms are evaluated only during the given SITUATION in the specified
  58 FORM-LANGUAGE (either :lisp or :parenscript, def, defaulting to :lisp during
  59 -toplevel and :parenscript during :execute). The accepted SITUATIONS are :execute,
  60 :scan-toplevel. :scan-toplevel is the phase of compilation when function definitions
  61 and the like are being added to the compilation environment. :execute is the phase when
  62 the code is being evaluated by a Javascript engine."
  63   (multiple-value-bind (body-language situations subforms)
  64       (process-eval-when-args args)
  65 ;    (format t "~A~%~A~%"
  66 ;          (and (compiler-in-situation-p *compilation-environment* :compile-toplevel)
  67 ;               (find :compile-toplevel situations))
  68 ;          (compiler-in-situation-p *compilation-environment*  :execute)
  69 ;           (find :execute situations))
  70     (cond
  71       ((and (compiler-in-situation-p *compilation-environment* :compile-toplevel)
  72             (find :compile-toplevel situations))
  73        (error "Should never be processing eval-when :COMPILE-TOPLEVEL forms from here."))
  74
  75       ((and (compiler-in-situation-p *compilation-environment*  :execute)
  76             (find :execute situations))
  77        (when (eql body-language :parenscript)
  78          (let ((form `(progn ,@subforms)))
  79 ;          (format t "Form: ~A~%" form)
  80            (compile-to-statement form)))))))
  81
  82 ;;; script packages
  83 (defscriptmacro defpackage (name &rest options)
  84   "Defines a Parenscript package."
  85   (labels ((opt-name (opt) (if (listp opt) (car opt) opt)))
  86   (let ((nicknames nil) (lisp-package nil) (secondary-lisp-packages nil)
  87         (exports nil) (used-packages nil) (documentation nil))
  88     (dolist (opt options)
  89       (case (opt-name opt)
  90         (:lisp-package (setf lisp-package (second opt)))
  91         (:nicknames (setf nicknames (rest opt)))
  92         (:secondary-lisp-packages secondary-lisp-packages t)
  93         (:export (setf exports (rest opt)))
  94         (:use (setf used-packages (rest opt)))
  95         (:documentation (setf documentation (second opt)))
  96         (t (error "Unknown option in DEFPACKAGE: ~A" (opt-name opt)))))
  97     (create-script-package
  98      *compilation-environment*
  99      :name name
 100      :nicknames nicknames
 101      :secondary-lisp-packages secondary-lisp-packages
 102      :used-packages used-packages
 103      :lisp-package lisp-package
 104      :exports exports
 105      :documentation documentation)))
 106   `(progn))
 107
 108 (defscriptmacro in-package (package-designator)
 109   "Changes the current script package in the parenscript compilation environment.  This mostly
 110 affects the reader and how it interns non-prefixed symbols"
 111   (let ((script-package
 112          (find-script-package package-designator *compilation-environment*)))
 113     (when (null script-package)
 114       (error "~A does not designate any script package.  Available script package: ~A"
 115              package-designator
 116              (mapcar #'script-package-name (comp-env-script-packages *compilation-environment*))))
 117     (setf (comp-env-current-package *compilation-environment*)
 118           script-package)
 119     `(progn)))
 120
 121 (defscriptmacro case (value &rest clauses)
 122   (labels ((make-clause (val body more)
 123              (cond ((listp val)
 124                     (append (mapcar #'list (butlast val))
 125                             (make-clause (first (last val)) body more)))
 126                    ((member val '(t otherwise))
 127                     (make-clause 'default body more))
 128                    (more `((,val ,@body break)))
 129                    (t `((,val ,@body))))))
 130     `(switch ,value ,@(mapcon #'(lambda (x)
 131                                   (make-clause (car (first x))
 132                                                (cdr (first x))
 133                                                (rest x)))
 134                               clauses))))
 135
 136 ;;; let
 137 (define-script-special-form let (decls &rest body)
 138   (let ((defvars (mapcar #'(lambda (decl)
 139                              (if (atom decl)
 140                                  (make-instance 'ps-js::js-defvar
 141                                        :names (list (compile-to-symbol decl))
 142                                        :value nil)
 143                                  (let ((name (first decl))
 144                                        (value (second decl)))
 145                                    (make-instance 'ps-js::js-defvar
 146                                                   :names (list (compile-to-symbol name))
 147                                                   :value (compile-to-expression value)))))
 148                          decls)))
 149     (make-instance 'ps-js::js-sub-block
 150                    :indent "  "
 151                    :statements (nconc defvars
 152                                  (mapcar #'compile-to-statement body)))))
 153
 154 ;;; iteration
 155 (defscriptmacro dotimes (iter &rest body)
 156   (let ((var (first iter))
 157         (times (second iter)))
 158   `(do ((,var 0 (1+ ,var)))
 159        ((>= ,var ,times))
 160      ,@body)))
 161
 162 (defscriptmacro dolist (i-array &rest body)
 163   (let ((var (first i-array))
 164         (array (second i-array))
 165         (arrvar (script-gensym "arr"))
 166         (idx (script-gensym "i")))
 167     `(let ((,arrvar ,array))
 168       (do ((,idx 0 (1+ ,idx)))
 169           ((>= ,idx (slot-value ,arrvar 'length)))
 170         (let ((,var (aref ,arrvar ,idx)))
 171           ,@body)))))
 172
 173 ;;; macros
 174 (defmacro with-temp-macro-environment ((var) &body body)
 175   `(let* ((,var (make-macro-env-dictionary))
 176           (*script-macro-env* (cons ,var *script-macro-env*)))
 177     ,@body))
 178
 179 (define-script-special-form macrolet (macros &body body)
 180   (with-temp-macro-environment (macro-env-dict)
 181     (dolist (macro macros)
 182       (destructuring-bind (name arglist &body body)
 183           macro
 184         (setf (get-macro-spec name macro-env-dict)
 185               (cons nil (let ((args (gensym "ps-macrolet-args-")))
 186                           (compile nil `(lambda (&rest ,args)
 187                                          (destructuring-bind ,arglist
 188                                              ,args
 189                                            ,@body))))))))
 190     (compile-script-form `(progn ,@body))))
 191
 192 (define-script-special-form symbol-macrolet (symbol-macros &body body)
 193   (with-temp-macro-environment (macro-env-dict)
 194     (dolist (macro symbol-macros)
 195       (destructuring-bind (name &body expansion)
 196           macro
 197         (setf (get-macro-spec name macro-env-dict)
 198               (cons t (compile nil `(lambda () ,@expansion))))))
 199     (compile-script-form `(progn ,@body))))
 200
 201 (defscriptmacro defmacro (name args &body body)
 202   `(lisp (defscriptmacro ,name ,args ,@body) nil))
 203
 204 (defscriptmacro define-symbol-macro (name &body body)
 205   `(lisp (define-script-symbol-macro ,name ,@body)))
 206
 207 (defscriptmacro lisp (&body forms)
 208   "Evaluates the given forms in Common Lisp at ParenScript
 209 macro-expansion time. The value of the last form is treated as a
 210 ParenScript expression and is inserted into the generated Javascript
 211 \(use nil for no-op)."
 212   (eval (cons 'progn forms)))
 213
 214 (defscriptmacro rebind (variables &body body)
 215   "Creates a new js lexical environment and copies the given
 216 variable(s) there. Executes the body in the new environment. This
 217 has the same effect as a new (let () ...) form in lisp but works on
 218 the js side for js closures."
 219   (unless (listp variables)
 220     (setf variables (list variables)))
 221   `((lambda ()
 222       (let ((new-context (new *object)))
 223         ,@(loop for variable in variables
 224                 collect `(setf (slot-value new-context ,(symbol-to-js variable))
 225                                ,variable))
 226         (with new-context
 227           ,@body)))))
 228
 229 (defscriptmacro with-slots (slots object &rest body)
 230   (flet ((slot-var (slot) (if (listp slot) (first slot) slot))
 231          (slot-symbol (slot) (if (listp slot) (second slot) slot)))
 232     `(symbol-macrolet ,(mapcar #'(lambda (slot)
 233                                    `(,(slot-var slot) '(slot-value ,object ',(slot-symbol slot))))
 234                                slots)
 235       ,@body)))
 236
 237 (eval-when (:compile-toplevel :load-toplevel :execute)
 238   (defun parse-function-body (body)
 239     ;; (format t "parsing function body ~A~%" body)
 240     (let* ((documentation
 241             (when (stringp (first body))
 242               (first body)))
 243            (body-forms (if documentation (rest body) body)))
 244       (values
 245        body-forms
 246        documentation)))
 247
 248   (defun parse-key-spec (key-spec)
 249     "parses an &key parameter.  Returns 4 values:
 250 var, init-form,  keyword-name, supplied-p-var, init-form-supplied-p.
 251
 252 Syntax of key spec:
 253 [&key {var | ({var | (keyword-name var)} [init-form [supplied-p-parameter]])}*
 254 "
 255     (let* ((var (cond ((symbolp key-spec) key-spec)
 256                       ((and (listp key-spec) (symbolp (first key-spec))) (first key-spec))
 257                       ((and (listp key-spec) (listp (first key-spec)))   (second key-spec))))
 258            (keyword-name (if (and (listp key-spec) (listp (first key-spec)))
 259                              (first (first key-spec))
 260                              (intern (string var) :keyword)))
 261            (init-form (if (listp key-spec) (second key-spec) nil))
 262            (init-form-supplied-p (if (listp key-spec) t nil))
 263            (supplied-p-var (if (listp key-spec) (third key-spec) nil)))
 264       (values var init-form keyword-name supplied-p-var init-form-supplied-p)))
 265
 266   (defun parse-optional-spec (spec)
 267     "Parses an &optional parameter.  Returns 3 values: var, init-form, supplied-p-var.
 268 [&optional {var | (var [init-form [supplied-p-parameter]])}*] "
 269     (let* ((var (cond ((symbolp spec) spec)
 270                       ((and (listp spec) (first spec)))))
 271            (init-form (if (listp spec) (second spec)))
 272            (supplied-p-var (if (listp spec) (third spec))))
 273       (values var init-form supplied-p-var)))
 274
 275   (defun parse-aux-spec (spec)
 276     "Returns two values: variable and init-form"
 277 ;; [&aux {var | (var [init-form])}*])
 278     (values (if (symbolp spec) spec (first spec))
 279             (when (listp spec) (second spec))))
 280
 281   (defun parse-extended-function (lambda-list body &optional name)
 282     "Returns two values: the effective arguments and body for a function with
 283 the given lambda-list and body."
 284
 285 ;; The lambda list is transformed as follows, since a javascript lambda list is just a
 286 ;; list of variable names, and you have access to the arguments variable inside the function:
 287 ;; * standard variables are the mapped directly into the js-lambda list
 288 ;; * optional variables' variable names are mapped directly into the lambda list,
 289 ;;   and for each optional variable with name v and default value d, a form is produced
 290 ;;   (defaultf v d)
 291 ;; * when any keyword variables are in the lambda list, a single 'options' variable is
 292 ;;   appended to the js-lambda list as the last argument.  WITH-SLOTS is used for all
 293 ;;   the variables with  inside the body of the function,
 294     ;;   a (with-slots ((var-name key-name)) options ...)
 295     (declare (ignore name))
 296     (multiple-value-bind (requireds optionals rest? rest keys? keys)
 297         (parse-lambda-list lambda-list)
 298       ;; (format t "~A .." rest)
 299       (let* ((options-var 'options)
 300              ;; optionals are of form (var default-value)
 301              (effective-args
 302               (remove-if
 303                #'null
 304                (append requireds
 305                        (mapcar #'parse-optional-spec optionals)
 306                        (when keys (list options-var)))))
 307              ;; an alist of arg -> default val
 308              (initform-pairs
 309               (remove
 310                nil
 311                (append
 312                 ;; optional arguments first
 313                 (mapcar #'(lambda (opt-spec)
 314                             (multiple-value-bind (var val) (parse-optional-spec opt-spec)
 315                               (cons var val)))
 316                         optionals)
 317                 (if keys? (list (cons options-var '(create))))
 318                 (mapcar #'(lambda (key-spec)
 319                             (multiple-value-bind (var val x y specified?) (parse-key-spec key-spec)
 320                               (declare (ignore x y))
 321                               (when specified? (cons var val))))
 322                         keys))))
 323              (body-paren-forms (parse-function-body body)) ;remove documentation
 324              ;;
 325              (initform-forms
 326               (mapcar #'(lambda (default-pair)
 327                           `(defaultf ,(car default-pair) ,(cdr default-pair)))
 328                       initform-pairs))
 329              (rest-form
 330               (if rest?
 331                   `(defvar ,rest (:.slice (to-array arguments)
 332                                   ,(length effective-args)))
 333                   `(progn)))
 334              (effective-body   (append initform-forms (list rest-form) body-paren-forms))
 335              (effective-body
 336               (if keys?
 337                   (list `(with-slots ,(mapcar #'(lambda (key-spec)
 338                                                   (multiple-value-bind (var x key-name)
 339                                                       (parse-key-spec key-spec)
 340                                                     (declare (ignore x))
 341                                                     (list var key-name)))
 342                                               keys)
 343                           ,options-var
 344                           ,@effective-body))
 345                   effective-body)))
 346         (values effective-args effective-body)))))
 347
 348 (ps:defscriptmacro defun (name lambda-list &body body)
 349   "An extended defun macro that allows cool things like keyword arguments.
 350 lambda-list::=
 351  (var*
 352   [&optional {var | (var [init-form [supplied-p-parameter]])}*]
 353   [&rest var]
 354   [&key {var | ({var | (keyword-name var)} [init-form [supplied-p-parameter]])}* [&allow-other-keys]]
 355   [&aux {var | (var [init-form])}*])"
 356   (multiple-value-bind (effective-args effective-body)
 357       (parse-extended-function lambda-list body name)
 358     `(%js-defun ,name ,effective-args
 359       ,@effective-body)))
 360
 361
 362 (ps:defscriptmacro lambda (lambda-list &body body)
 363   "An extended defun macro that allows cool things like keyword arguments.
 364 lambda-list::=
 365  (var*
 366   [&optional {var | (var [init-form [supplied-p-parameter]])}*]
 367   [&rest var]
 368   [&key {var | ({var | (keyword-name var)} [init-form [supplied-p-parameter]])}* [&allow-other-keys]]
 369   [&aux {var | (var [init-form])}*])"
 370   (multiple-value-bind (effective-args effective-body)
 371       (parse-extended-function lambda-list body)
 372     `(%js-lambda ,effective-args
 373       ,@effective-body)))
 374
 375 (defpsmacro defsetf (access-fn lambda-list (store-var) form)
 376   (setf (find-macro-spec access-fn *script-setf-expanders*)
 377         (compile nil
 378                  (let ((var-bindings (set-difference lambda-list lambda-list-keywords)))
 379                    `(lambda (access-fn-args store-form)
 380                      (destructuring-bind ,lambda-list
 381                                access-fn-args
 382                        (let* ((,store-var (ps:gen-ps-name))
 383                               (gensymed-names (loop repeat ,(length var-bindings) collecting (ps:gen-ps-name)))
 384                               (gensymed-arg-bindings (mapcar #'list gensymed-names (list ,@var-bindings))))
 385                          (destructuring-bind ,var-bindings
 386                              gensymed-names
 387                            `(let ((,,store-var ,store-form)
 388                                   ,@gensymed-arg-bindings)
 389                              ,,form))))))))
 390   nil)
 391
 392 (defpsmacro setf (&rest args)
 393   (flet ((process-setf-clause (place value-form)
 394            (if (and (listp place) (find-macro-spec (car place) *script-setf-expanders*))
 395                (funcall (find-macro-spec (car place) *script-setf-expanders*) (cdr place) value-form)
 396                (let ((exp-place (expand-script-form place)))
 397                  (if (and (listp exp-place) (find-macro-spec (car exp-place) *script-setf-expanders*))
 398                      (funcall (find-macro-spec (car exp-place) *script-setf-expanders*) (cdr exp-place) value-form)
 399                      `(parenscript.javascript::setf1% ,exp-place ,value-form))))))
 400     (assert (evenp (length args)) ()
 401             "~s does not have an even number of arguments." (cons 'setf args))
 402     `(progn ,@(loop for (place value) on args by #'cddr collect (process-setf-clause place value)))))