src/compiler.lisp

   1 (in-package "PARENSCRIPT")
   2
   3 ;;; reserved symbols/literals
   4
   5 (defvar *ps-reserved-symbol-names*
   6   (list "break" "case" "catch" "continue" "default" "delete" "do" "else"
   7         "finally" "for" "function" "if" "in" "instanceof" "new" "return"
   8         "switch" "this" "throw" "try" "typeof" "var" "void" "while" "with"
   9         "abstract" "boolean" "byte" "char" "class" "const" "debugger" "double"
  10         "enum" "export" "extends" "final" "float" "goto" "implements" "import"
  11         "int" "interface" "long" "native" "package" "private" "protected"
  12         "public" "short" "static" "super" "synchronized" "throws" "transient"
  13         "volatile"))
  14
  15 (defun add-ps-reserved-symbol (name)
  16   (pushnew (symbol-name-to-js-string name) *ps-reserved-symbol-names* :test #'equalp))
  17
  18 (defun ps-reserved-symbol-p (symbol)
  19   (when (symbolp symbol)
  20     (find (symbol-name-to-js-string symbol) *ps-reserved-symbol-names* :test #'equalp)))
  21
  22 ;;; special forms
  23
  24 (defvar *ps-special-forms* (make-hash-table :test 'eq))
  25
  26 (defun get-ps-special-form (name)
  27   (gethash name *ps-special-forms*))
  28
  29 (defmacro define-ps-special-form (name lambda-list &rest body)
  30   `(setf (gethash ',name *ps-special-forms*)
  31          (lambda (&rest whole)
  32            (destructuring-bind ,lambda-list
  33                whole
  34              ,@body))))
  35
  36 (defun undefine-ps-special-form (name)
  37   (remhash name *ps-special-forms*))
  38
  39 (defun ps-special-form-p (form)
  40   (and (consp form)
  41        (symbolp (car form))
  42        (gethash (car form) *ps-special-forms*)))
  43
  44 ;;; scoping
  45
  46 (defvar *enclosing-lexical-block-declarations* ()
  47   "This special variable is expected to be bound to a fresh list by
  48 special forms that introduce a new JavaScript lexical block (currently
  49 function definitions and lambdas). Enclosed special forms are expected
  50 to push variable declarations onto the list when the variables
  51 declaration cannot be made by the enclosed form \(for example, a
  52 \(x,y,z\) expression progn\). It is then the responsibility of the
  53 enclosing special form to introduce the variable bindings in its
  54 lexical block.")
  55
  56 (defvar *ps-special-variables* ())
  57
  58 (defun ps-special-variable-p (sym)
  59   (member sym *ps-special-variables*))
  60
  61 ;;; form predicates
  62
  63 (defun comparison-form-p (form)
  64   (member (car form) '(< > <= >= == != === !==)))
  65
  66 (defun op-form-p (form)
  67   (and (listp form)
  68        (not (ps-special-form-p form))
  69        (not (null (op-precedence (first form))))))
  70
  71 (defun funcall-form-p (form)
  72   (and form
  73        (listp form)
  74        (not (op-form-p form))
  75        (not (ps-special-form-p form))))
  76
  77 ;;; macro expansion
  78 (eval-when (:compile-toplevel :load-toplevel :execute)
  79   (defun make-macro-dictionary ()
  80     (make-hash-table :test 'eq))
  81
  82   (defvar *ps-macro-toplevel* (make-macro-dictionary)
  83     "Toplevel macro environment dictionary.")
  84
  85   (defvar *ps-macro-env* (list *ps-macro-toplevel*)
  86     "Current macro environment.")
  87
  88   (defvar *ps-symbol-macro-toplevel* (make-macro-dictionary))
  89
  90   (defvar *ps-symbol-macro-env* (list *ps-symbol-macro-toplevel*))
  91
  92   (defvar *ps-local-function-names* ())
  93
  94   (defvar *ps-setf-expanders* (make-macro-dictionary)
  95     "Setf expander dictionary. Key is the symbol of the access
  96 function of the place, value is an expansion function that takes the
  97 arguments of the access functions as a first value and the form to be
  98 stored as the second value.")
  99
 100   (defparameter *ps-compilation-level* :toplevel
 101     "This value takes on the following values:
 102 :toplevel indicates that we are traversing toplevel forms.
 103 :inside-toplevel-form indicates that we are inside a call to ps-compile-*
 104 nil indicates we are no longer toplevel-related."))
 105
 106 (defun lookup-macro-def (name env)
 107   (loop for e in env thereis (gethash name e)))
 108
 109 (defun make-ps-macro-function (args body)
 110   (let* ((whole-var (when (eql '&whole (first args)) (second args)))
 111          (effective-lambda-list (if whole-var (cddr args) args))
 112          (whole-arg (or whole-var (gensym "ps-macro-form-arg-"))))
 113     `(lambda (,whole-arg)
 114        (destructuring-bind ,effective-lambda-list
 115            (cdr ,whole-arg)
 116          ,@body))))
 117
 118 (defmacro defpsmacro (name args &body body)
 119   `(progn (undefine-ps-special-form ',name)
 120           (setf (gethash ',name *ps-macro-toplevel*) ,(make-ps-macro-function args body))
 121           ',name))
 122
 123 (defmacro define-ps-symbol-macro (symbol expansion)
 124   (let ((x (gensym)))
 125     `(progn (undefine-ps-special-form ',symbol)
 126             (setf (gethash ',symbol *ps-symbol-macro-toplevel*) (lambda (,x) (declare (ignore ,x)) ',expansion))
 127             ',symbol)))
 128
 129 (defun import-macros-from-lisp (&rest names)
 130   "Import the named Lisp macros into the ParenScript macro
 131 environment. When the imported macro is macroexpanded by ParenScript,
 132 it is first fully macroexpanded in the Lisp macro environment, and
 133 then that expansion is further expanded by ParenScript."
 134   (dolist (name names)
 135     (eval `(defpsmacro ,name (&rest args)
 136              (macroexpand `(,',name ,@args))))))
 137
 138 (defmacro defmacro/ps (name args &body body)
 139   "Define a Lisp macro and import it into the ParenScript macro environment."
 140   `(progn (defmacro ,name ,args ,@body)
 141           (import-macros-from-lisp ',name)))
 142
 143 (defmacro defmacro+ps (name args &body body)
 144   "Define a Lisp macro and a ParenScript macro with the same macro
 145 function (ie - the same result from macroexpand-1), for cases when the
 146 two have different full macroexpansions (for example if the CL macro
 147 contains implementation-specific code when macroexpanded fully in the
 148 CL environment)."
 149   `(progn (defmacro ,name ,args ,@body)
 150           (defpsmacro ,name ,args ,@body)))
 151
 152 (defun ps-macroexpand (form)
 153   (aif (or (and (symbolp form) (lookup-macro-def form *ps-symbol-macro-env*))
 154            (and (consp form) (lookup-macro-def (car form) *ps-macro-env*)))
 155        (values (ps-macroexpand (funcall it form)) t)
 156        form))
 157
 158 (defun maybe-rename-local-function (fun-name)
 159   (aif (lookup-macro-def fun-name *ps-local-function-names*)
 160        it
 161        fun-name))
 162
 163 ;;;; compiler interface
 164 (defun adjust-ps-compilation-level (form level)
 165   "Given the current *ps-compilation-level*, LEVEL, and the fully macroexpanded
 166 form, FORM, returns the new value for *ps-compilation-level*."
 167   (cond ((or (and (consp form) (member (car form)
 168                        '(progn locally macrolet symbol-macrolet compile-file)))
 169          (and (symbolp form) (eq :toplevel level)))
 170      level)
 171     ((eq :toplevel level) :inside-toplevel-form)))
 172
 173
 174 (defun ps-compile-symbol (form)
 175   "Compiles the given Parenscript form and guarantees that the
 176 resultant symbol has an associated script-package. Raises an error if
 177 the form cannot be compiled to a symbol."
 178   (let ((exp (ps-compile-expression form)))
 179     (when (eq (first exp) 'js:variable)
 180       (setf exp (second exp)))
 181     (assert (symbolp exp) ()
 182             "~a is expected to be a symbol, but compiles to ~a (the ParenScript output for ~a alone is \"~a\"). This could be due to ~a being a special form." form exp form (ps* form) form)
 183     exp))
 184
 185 (defmethod ps-compile (form)
 186   (error "The object ~S cannot be compiled by ParenScript." form))
 187
 188 (defmethod ps-compile ((form number))
 189   form)
 190
 191 (defmethod ps-compile ((form string))
 192   form)
 193
 194 (defmethod ps-compile ((form character))
 195   (ps-compile (string form)))
 196
 197 (defmethod ps-compile ((symbol symbol))
 198   (when (eq *ps-compilation-level* :toplevel)
 199     (multiple-value-bind (expansion expanded-p)
 200         (ps-macroexpand symbol)
 201       (when expanded-p
 202         (return-from ps-compile (ps-compile expansion)))))
 203   (cond ((keywordp symbol) symbol)
 204         ((ps-special-form-p (list symbol))
 205          (if (ps-reserved-symbol-p symbol)
 206              (funcall (get-ps-special-form symbol))
 207              (error "Attempting to use Parenscript special form ~a as variable" symbol)))
 208         (t `(js:variable ,symbol))))
 209
 210 ;;; operators
 211
 212 (let ((precedence-table (make-hash-table :test 'eq)))
 213   (loop for level in '((js:new js:slot-value js:aref)
 214                        (postfix++ postfix--)
 215                        (delete void typeof ++ -- unary+ unary- ~ !)
 216                        (* / %)
 217                        (+ -)
 218                        (<< >> >>>)
 219                        (< > <= >= js:instanceof js:in)
 220                        (== != === !==)
 221                        (&)
 222                        (^)
 223                        (\|)
 224                        (\&\& and)
 225                        (\|\| or)
 226                        (js:?)
 227                        (= *= /= %= += -= <<= >>= >>>= \&\= ^= \|=)
 228                        (comma))
 229      for i from 0
 230      do (mapcar (lambda (symbol)
 231                   (setf (gethash symbol precedence-table) i))
 232                 level))
 233   (defun op-precedence (op)
 234     (gethash op precedence-table)))
 235
 236 (defun ps-convert-op-name (op)
 237   (case op
 238     (and '\&\&)
 239     (or '\|\|)
 240     (not '!)
 241     (eql '\=\=)
 242     (=   '\=\=)
 243    (t op)))
 244
 245 (defun maybe-fix-nary-comparison-form (form)
 246   (if (< 2 (length (cdr form)))
 247       (values
 248        (let* ((operator (car form))
 249               (tmp-var-forms (butlast (cddr form)))
 250               (tmp-vars (loop repeat (length tmp-var-forms)
 251                            collect (ps-gensym "_cmp")))
 252               (all-comparisons (append (list (cadr form))
 253                                        tmp-vars
 254                                        (last form))))
 255          `(let ,(mapcar #'list tmp-vars tmp-var-forms)
 256             (and ,@(loop for x1 in all-comparisons
 257                       for x2 in (cdr all-comparisons)
 258                       collect (list operator x1 x2)))))
 259        t)
 260       form))
 261
 262 (defun compile-op-form (form)
 263   `(js:operator ,(ps-convert-op-name (ps-compile-symbol (car form)))
 264                 ,@(mapcar (lambda (form)
 265                             (ps-compile-expression (ps-macroexpand form)))
 266                           (cdr form))))
 267
 268 (defun compile-funcall-form (form)
 269   `(js:funcall
 270     ,(ps-compile-expression (if (symbolp (car form))
 271                                 (maybe-rename-local-function (car form))
 272                                 (ps-macroexpand (car form))))
 273     ,@(mapcar #'ps-compile-expression (cdr form))))
 274
 275 (defvar compile-expression?)
 276
 277 (defmethod ps-compile ((form cons))
 278   (multiple-value-bind (form expanded-p)
 279       (ps-macroexpand form)
 280     (let ((*ps-compilation-level*
 281            (if expanded-p
 282                *ps-compilation-level*
 283                (adjust-ps-compilation-level form *ps-compilation-level*))))
 284       (cond (expanded-p
 285              (ps-compile form))
 286             ((ps-special-form-p form)
 287              (apply (get-ps-special-form (car form)) (cdr form)))
 288             ((comparison-form-p form)
 289              (multiple-value-bind (form fixed?)
 290                  (maybe-fix-nary-comparison-form form)
 291                (if fixed?
 292                    (ps-compile form)
 293                    (compile-op-form form))))
 294             ((op-form-p form)
 295              (compile-op-form form))
 296             ((funcall-form-p form)
 297              (compile-funcall-form form))
 298             (t (error "Cannot compile ~S to a ParenScript form." form))))))
 299
 300 (defun ps-compile-statement (form)
 301   (let ((compile-expression? nil))
 302     (ps-compile form)))
 303
 304 (defun ps-compile-expression (form)
 305   (let ((compile-expression? t))
 306     (ps-compile form)))
 307
 308 (defvar *ps-gensym-counter* 0)
 309
 310 (defun ps-gensym (&optional (prefix "_js"))
 311   (let ((prefix (if (stringp prefix) prefix (symbol-to-js-string prefix nil))))
 312     (make-symbol (format nil "~A~:[~;_~]~A" prefix
 313                          (digit-char-p (char prefix (1- (length prefix))))
 314                          (incf *ps-gensym-counter*)))))
 315
 316 (defmacro with-ps-gensyms (symbols &body body)
 317   "Evaluate BODY with SYMBOLS bound to unique ParenScript identifiers.
 318
 319 Each element of SYMBOLS is either a symbol or a list of (symbol
 320 gensym-prefix-string)."
 321   `(let* ,(mapcar (lambda (symbol)
 322                     (destructuring-bind (symbol &optional prefix)
 323                         (if (consp symbol)
 324                             symbol
 325                             (list symbol))
 326                       (if prefix
 327                           `(,symbol (ps-gensym ,prefix))
 328                           `(,symbol (ps-gensym ,(symbol-to-js-string symbol))))))
 329                   symbols)
 330      ,@body))
 331
 332 (defun %check-once-only-vars (vars)
 333   (let ((bad-var (find-if (lambda (x) (or (not (symbolp x)) (keywordp x))) vars)))
 334     (when bad-var
 335       (error "PS-ONLY-ONCE expected a non-keyword symbol but got ~s" bad-var))))
 336
 337 (defmacro ps-once-only ((&rest vars) &body body)
 338   (%check-once-only-vars vars)
 339   (let ((gensyms (mapcar (lambda (x) (ps-gensym (string x))) vars)))
 340     `(let ,(mapcar (lambda (g v) `(,g (ps-gensym ,(string v)))) gensyms vars)
 341        `(let* (,,@(mapcar (lambda (g v) ``(,,g ,,v)) gensyms vars))
 342           ,(let ,(mapcar (lambda (g v) `(,v ,g)) gensyms vars)
 343              ,@body)))))