-(in-package :parenscript)
-
-(eval-when (:compile-toplevel :load-toplevel :execute)
- (defvar *toplevel-special-forms* (make-hash-table :test #'equal)
- "A hash-table containing functions that implement Parenscript special forms,
-indexed by name (as symbols)")
- (defun undefine-ps-special-form (name)
- "Undefines the special form with the given name (name is a symbol)."
- (remhash (lisp-symbol-to-ps-identifier name :special-form) *toplevel-special-forms*)))
-
-(defmacro define-ps-special-form (name lambda-list &rest body)
- "Define a special form NAME. The first argument given to the special
-form is a keyword indicating whether the form is expected to produce
-an :expression or a :statement. The resulting Parenscript language
-types are appended to the ongoing javascript compilation."
- (let ((arglist (gensym "ps-arglist-")))
- `(setf (gethash (lisp-symbol-to-ps-identifier ',name :special-form) *toplevel-special-forms*)
- (lambda (&rest ,arglist)
- (destructuring-bind ,lambda-list
- ,arglist
- ,@body)))))
-
-(defun get-ps-special-form (name)
- "Returns the special form function corresponding to the given name."
- (gethash (lisp-symbol-to-ps-identifier name :special-form) *toplevel-special-forms*))
-
-(defvar *enclosing-lexical-block-declarations* ()
- "This special variable is expected to be bound to a fresh list by
-special forms that introduce a new JavaScript lexical block (currently
-function definitions and lambdas). Enclosed special forms are expected
-to push variable declarations onto the list when the variables
-declaration cannot be made by the enclosed form (for example, a
-(x,y,z) expression progn). It is then the responsibility of the
-enclosing special form to introduce the variable bindings in its
-lexical block.")
-
-;;; ParenScript form predicates
-(defun ps-special-form-p (form)
- (and (consp form)
- (symbolp (car form))
- (get-ps-special-form (car form))))
-
-(defun op-form-p (form)
- (and (listp form)
- (not (ps-special-form-p form))
- (not (null (op-precedence (first form))))))
-
-(defun funcall-form-p (form)
- (and (listp form)
- (not (op-form-p form))
- (not (ps-special-form-p form))))
-
-(defun method-call-p (form)
- (and (funcall-form-p form)
- (symbolp (first form))
- (eql (char (symbol-name (first form)) 0) #\.)))
-
-;;; macro expansion
-(eval-when (:compile-toplevel :load-toplevel :execute)
- (defun make-macro-env-dictionary ()
- "Creates a standard macro dictionary."
- (make-hash-table :test #'equal))
- (defvar *script-macro-toplevel* (make-macro-env-dictionary)
- "Toplevel macro environment dictionary. Key is the symbol of the
-macro, value is (symbol-macro-p . expansion-function).")
- (defvar *script-macro-env* (list *script-macro-toplevel*)
- "Current macro environment.")
-
- (defvar *script-setf-expanders* (make-macro-env-dictionary)
- "Setf expander dictionary. Key is the symbol of the access
-function of the place, value is an expansion function that takes the
-arguments of the access functions as a first value and the form to be
-stored as the second value.")
-
- (defun get-macro-spec (name env-dict)
- "Retrieves the macro spec of the given name with the given environment dictionary.
-SPEC is of the form (symbol-macro-p . expansion-function)."
- (gethash (lisp-symbol-to-ps-identifier name :macro) env-dict))
- (defsetf get-macro-spec (name env-dict)
- (spec)
- `(setf (gethash (lisp-symbol-to-ps-identifier ,name :macro) ,env-dict) ,spec)))
-
-(defun lookup-macro-spec (name &optional (environment *script-macro-env*))
- "Looks up the macro spec associated with NAME in the given environment. A
-macro spec is of the form (symbol-macro-p . function). Returns two values:
-the SPEC and the parent macro environment.
-
-NAME must be a symbol."
- (when (symbolp name)
- (do ((env environment (cdr env)))
- ((null env) nil)
- (let ((val (get-macro-spec name (car env))))
- (when val
- (return-from lookup-macro-spec
- (values val (or (cdr env)
- (list *script-macro-toplevel*)))))))))
-
-(defun script-symbol-macro-p (name &optional (environment *script-macro-env*))
- "True if there is a Parenscript symbol macro named by the symbol NAME."
- (and (symbolp name) (car (lookup-macro-spec name environment))))
-
-(defun script-macro-p (name &optional (environment *script-macro-env*))
- "True if there is a Parenscript macro named by the symbol NAME."
- (and (symbolp name)
- (let ((macro-spec (lookup-macro-spec name environment)))
- (and macro-spec (not (car macro-spec))))))
-
-(defun lookup-macro-expansion-function (name &optional (environment *script-macro-env*))
- "Lookup NAME in the given macro expansion environment (which
-defaults to the current macro environment). Returns the expansion
-function and the parent macro environment of the macro."
- (multiple-value-bind (macro-spec parent-env)
- (lookup-macro-spec name environment)
- (values (cdr macro-spec) parent-env)))
-
-(eval-when (:compile-toplevel :load-toplevel :execute)
- (defun make-ps-macro-function (args body)
- (let* ((whole-var (when (eql '&whole (first args)) (second args)))
- (effective-lambda-list (if whole-var (cddr args) args))
- (form-arg (or whole-var (gensym "ps-macro-form-arg-")))
- (body (if (and (cdr body) (stringp (first body))) (rest body) body))) ;; drop docstring
- (compile nil `(lambda (,form-arg)
- (destructuring-bind ,effective-lambda-list
- (cdr ,form-arg)
- ,@body)))))
-
- (defun define-script-macro% (name args body &key symbol-macro-p)
- (undefine-ps-special-form name)
- (setf (get-macro-spec name *script-macro-toplevel*)
- (cons symbol-macro-p (make-ps-macro-function args body)))
- nil))
-
-(defmacro defpsmacro (name args &body body)
- "Define a ParenScript macro, and store it in the toplevel ParenScript
-macro environment."
- `(define-script-macro% ',name ',args ',body :symbol-macro-p nil))
-
-(defmacro define-script-symbol-macro (name &body body)
- "Define a ParenScript symbol macro, and store it in the toplevel ParenScript
-macro environment. BODY is a Lisp form that should return a ParenScript form."
- `(define-script-macro% ',name () ',body :symbol-macro-p t))
-
-(defun import-macros-from-lisp (&rest names)
- "Import the named Lisp macros into the ParenScript macro
-environment. When the imported macro is macroexpanded by ParenScript,
-it is first fully macroexpanded in the Lisp macro environment, and
-then that expansion is further expanded by ParenScript."
- (dolist (name names)
- (define-script-macro% name '(&rest args)
- (list `(common-lisp:macroexpand `(,',name ,@args)))
- :symbol-macro-p nil)))
-
-(defmacro defmacro/ps (name args &body body)
- "Define a Lisp macro and import it into the ParenScript macro environment."
- `(progn (defmacro ,name ,args ,@body)
- (ps:import-macros-from-lisp ',name)))
-
-(defmacro defmacro+ps (name args &body body)
- "Define a Lisp macro and a ParenScript macro in their respective
-macro environments. This function should be used when you want to use
-the same macro in both Lisp and ParenScript, but the 'macroexpand' of
-that macro in Lisp makes the Lisp macro unsuitable to be imported into
-the ParenScript macro environment."
- `(progn (defmacro ,name ,args ,@body)
- (defpsmacro ,name ,args ,@body)))
-
-(defun ps-macroexpand (form)
- "Recursively macroexpands ParenScript macros and symbol-macros in
-the given ParenScript form. Returns two values: the expanded form, and
-whether any expansion was performed on the form or not."
- (if (consp form)
- (let ((op (car form))
- (args (cdr form)))
- (cond ((equal op 'quote) (values (if (equalp '(nil) args) nil form) ;; leave quotes alone, unless it's a quoted nil
- nil))
- ((script-macro-p op) (values (ps-macroexpand (funcall (lookup-macro-expansion-function op) form)) t))
- (t (values form nil))))
- (cond ((script-symbol-macro-p form) (values (ps-macroexpand (funcall (lookup-macro-expansion-function form) (list form))) t))
- (t (values form nil)))))
-
-;;;; compiler interface
-(defgeneric compile-parenscript-form (form &key expecting)
- (:documentation "Compiles a ParenScript form to the intermediate
-ParenScript representation. :expecting determines whether the form is
-compiled to an :expression (the default), a :statement, or a
-:symbol."))
-
-(defmethod compile-parenscript-form :around (form &key expecting)
- (assert (if expecting (member expecting '(:expression :statement :symbol)) t))
- (if (eql expecting :symbol)
- (compile-to-symbol form)
- (multiple-value-bind (expanded-form expanded-p)
- (ps-macroexpand form)
- (if expanded-p
- (compile-parenscript-form expanded-form :expecting expecting)
- (call-next-method)))))
-
-(defun compile-to-symbol (form)
- "Compiles the given Parenscript form and guarantees that the
-resultant symbol has an associated script-package. Raises an error if
-the form cannot be compiled to a symbol."
- (let ((exp (compile-parenscript-form form)))
- (when (or (eql (first exp) 'js-variable)
- (eql (first exp) 'script-quote))
- (setf exp (second exp)))
- (assert (symbolp exp) ()
- "~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)
- exp))
-
-(defmethod compile-parenscript-form (form &key expecting)
- (declare (ignore expecting))
- (error "The object ~S cannot be compiled by ParenScript." form))
-
-(defmethod compile-parenscript-form ((form number) &key expecting)
- (declare (ignore expecting))
- form)
-
-(defmethod compile-parenscript-form ((form string) &key expecting)
- (declare (ignore expecting))
- form)
-
-(defmethod compile-parenscript-form ((form character) &key expecting)
- (declare (ignore expecting))
- (compile-parenscript-form (string form)))
-
-(defmethod compile-parenscript-form ((symbol symbol) &key expecting)
- (declare (ignore expecting))
- ;; is this the correct behavior?
- (let ((special-symbol (get-ps-special-form symbol)))
- (cond (special-symbol (funcall special-symbol :symbol))
- (t (list 'js-variable symbol)))))
-
-(defun compile-function-argument-forms (arg-forms)
- "Compiles a bunch of Parenscript forms from a funcall form to an effective set of
-Javascript arguments. The only extra processing this does is makes :keyword arguments
-into a single options argument via CREATE."
- (flet ((keyword-arg (arg)
- "If the given compiled expression is supposed to be a keyword argument, returns
-the keyword for it."
- (when (and (listp arg) (eql (first arg) 'script-quote)) (second arg))))
- (let ((compiled-args (mapcar (lambda (arg) (compile-parenscript-form arg :expecting :expression))
- arg-forms)))
- (do ((effective-expressions nil)
- (expressions-subl compiled-args))
- ((not expressions-subl) (reverse effective-expressions))
- (let ((arg-expr (first expressions-subl)))
- (if (keyword-arg arg-expr)
- (progn (when (oddp (length expressions-subl))
- (error "Odd number of keyword arguments: ~A." arg-forms))
- (push (list 'js-object (loop for (name val) on expressions-subl by #'cddr
- collect (list name val)))
- effective-expressions)
- (setf expressions-subl nil))
- (progn (push arg-expr effective-expressions)
- (setf expressions-subl (rest expressions-subl)))))))))
-
-(defmethod compile-parenscript-form ((form cons) &key (expecting :statement))
- (let* ((name (car form))
- (args (cdr form)))
- (cond ((eql name 'quote)
- (assert (= 1 (length args)) () "Wrong number of arguments to quote: ~s" args)
- (list 'script-quote (first args)))
- ((ps-special-form-p form) (apply (get-ps-special-form name) (cons expecting args)))
- ((op-form-p form)
- (list 'operator
- (script-convert-op-name (compile-parenscript-form (first form) :expecting :symbol))
- (mapcar (lambda (form) (compile-parenscript-form form :expecting :expression)) (rest form))))
- ((method-call-p form)
- (list 'js-method-call
- (compile-parenscript-form name :expecting :symbol)
- (compile-parenscript-form (first args) :expecting :expression)
- (compile-function-argument-forms (rest args))))
- ((funcall-form-p form)
- (list 'js-funcall
- (compile-parenscript-form name :expecting :expression)
- (compile-function-argument-forms args)))
- (t (error "Cannot compile ~S to a ParenScript form." form)))))
-
+(in-package "PARENSCRIPT")
+
+;;; reserved symbols/literals
+
+(defvar *ps-reserved-symbol-names*
+ (list "break" "case" "catch" "continue" "default" "delete" "do" "else"
+ "finally" "for" "function" "if" "in" "instanceof" "new" "return"
+ "switch" "this" "throw" "try" "typeof" "var" "void" "while" "with"
+ "abstract" "boolean" "byte" "char" "class" "const" "debugger" "double"
+ "enum" "export" "extends" "final" "float" "goto" "implements" "import"
+ "int" "interface" "long" "native" "package" "private" "protected"
+ "public" "short" "static" "super" "synchronized" "throws" "transient"
+ "volatile"))
+
+(defun add-ps-reserved-symbol (name)
+ (pushnew (symbol-name-to-js-string name) *ps-reserved-symbol-names* :test #'equalp))
+
+(defun ps-reserved-symbol-p (symbol)
+ (when (symbolp symbol)
+ (find (symbol-name-to-js-string symbol) *ps-reserved-symbol-names* :test #'equalp)))
+
+;;; special forms
+
+(defvar *ps-special-forms* (make-hash-table :test 'eq))
+
+(defun get-ps-special-form (name)
+ (gethash name *ps-special-forms*))
+
+(defmacro define-ps-special-form (name lambda-list &rest body)
+ `(setf (gethash ',name *ps-special-forms*)
+ (lambda (&rest whole)
+ (destructuring-bind ,lambda-list
+ whole
+ ,@body))))
+
+(defun undefine-ps-special-form (name)
+ (remhash name *ps-special-forms*))
+
+(defun ps-special-form-p (form)
+ (and (consp form)
+ (symbolp (car form))
+ (gethash (car form) *ps-special-forms*)))
+
+;;; scoping
+
+(defvar *enclosing-lexical-block-declarations* ()
+ "This special variable is expected to be bound to a fresh list by
+special forms that introduce a new JavaScript lexical block (currently
+function definitions and lambdas). Enclosed special forms are expected
+to push variable declarations onto the list when the variables
+declaration cannot be made by the enclosed form \(for example, a
+\(x,y,z\) expression progn\). It is then the responsibility of the
+enclosing special form to introduce the variable bindings in its
+lexical block.")
+
+(defvar *ps-special-variables* ())
+
+(defun ps-special-variable-p (sym)
+ (member sym *ps-special-variables*))
+
+;;; form predicates
+
+(defun comparison-form-p (form)
+ (member (car form) '(< > <= >= == != === !==)))
+
+(defun op-form-p (form)
+ (and (listp form)
+ (not (ps-special-form-p form))
+ (not (null (op-precedence (first form))))))
+
+(defun funcall-form-p (form)
+ (and form
+ (listp form)
+ (not (op-form-p form))
+ (not (ps-special-form-p form))))
+
+;;; macro expansion
+(eval-when (:compile-toplevel :load-toplevel :execute)
+ (defun make-macro-dictionary ()
+ (make-hash-table :test 'eq))
+
+ (defvar *ps-macro-toplevel* (make-macro-dictionary)
+ "Toplevel macro environment dictionary.")
+
+ (defvar *ps-macro-env* (list *ps-macro-toplevel*)
+ "Current macro environment.")
+
+ (defvar *ps-symbol-macro-toplevel* (make-macro-dictionary))
+
+ (defvar *ps-symbol-macro-env* (list *ps-symbol-macro-toplevel*))
+
+ (defvar *ps-local-function-names* ())
+
+ (defvar *ps-setf-expanders* (make-macro-dictionary)
+ "Setf expander dictionary. Key is the symbol of the access
+function of the place, value is an expansion function that takes the
+arguments of the access functions as a first value and the form to be
+stored as the second value.")
+
+ (defparameter *ps-compilation-level* :toplevel
+ "This value takes on the following values:
+:toplevel indicates that we are traversing toplevel forms.
+:inside-toplevel-form indicates that we are inside a call to ps-compile-*
+nil indicates we are no longer toplevel-related."))
+
+(defun lookup-macro-def (name env)
+ (loop for e in env thereis (gethash name e)))
+
+(defun make-ps-macro-function (args body)
+ (let* ((whole-var (when (eql '&whole (first args)) (second args)))
+ (effective-lambda-list (if whole-var (cddr args) args))
+ (whole-arg (or whole-var (gensym "ps-macro-form-arg-"))))
+ `(lambda (,whole-arg)
+ (destructuring-bind ,effective-lambda-list
+ (cdr ,whole-arg)
+ ,@body))))
+
+(defmacro defpsmacro (name args &body body)
+ `(progn (undefine-ps-special-form ',name)
+ (setf (gethash ',name *ps-macro-toplevel*) ,(make-ps-macro-function args body))
+ ',name))
+
+(defmacro define-ps-symbol-macro (symbol expansion)
+ (let ((x (gensym)))
+ `(progn (undefine-ps-special-form ',symbol)
+ (setf (gethash ',symbol *ps-symbol-macro-toplevel*) (lambda (,x) (declare (ignore ,x)) ',expansion))
+ ',symbol)))
+
+(defun import-macros-from-lisp (&rest names)
+ "Import the named Lisp macros into the ParenScript macro
+environment. When the imported macro is macroexpanded by ParenScript,
+it is first fully macroexpanded in the Lisp macro environment, and
+then that expansion is further expanded by ParenScript."
+ (dolist (name names)
+ (eval `(defpsmacro ,name (&rest args)
+ (macroexpand `(,',name ,@args))))))
+
+(defmacro defmacro/ps (name args &body body)
+ "Define a Lisp macro and import it into the ParenScript macro environment."
+ `(progn (defmacro ,name ,args ,@body)
+ (import-macros-from-lisp ',name)))
+
+(defmacro defmacro+ps (name args &body body)
+ "Define a Lisp macro and a ParenScript macro with the same macro
+function (ie - the same result from macroexpand-1), for cases when the
+two have different full macroexpansions (for example if the CL macro
+contains implementation-specific code when macroexpanded fully in the
+CL environment)."
+ `(progn (defmacro ,name ,args ,@body)
+ (defpsmacro ,name ,args ,@body)))
+
+(defun ps-macroexpand (form)
+ (aif (or (and (symbolp form) (lookup-macro-def form *ps-symbol-macro-env*))
+ (and (consp form) (lookup-macro-def (car form) *ps-macro-env*)))
+ (values (ps-macroexpand (funcall it form)) t)
+ form))
+
+(defun maybe-rename-local-function (fun-name)
+ (aif (lookup-macro-def fun-name *ps-local-function-names*)
+ it
+ fun-name))
+
+;;;; compiler interface
+(defun adjust-ps-compilation-level (form level)
+ "Given the current *ps-compilation-level*, LEVEL, and the fully macroexpanded
+form, FORM, returns the new value for *ps-compilation-level*."
+ (cond ((or (and (consp form) (member (car form)
+ '(progn locally macrolet symbol-macrolet compile-file)))
+ (and (symbolp form) (eq :toplevel level)))
+ level)
+ ((eq :toplevel level) :inside-toplevel-form)))
+
+
+(defun ps-compile-symbol (form)
+ "Compiles the given Parenscript form and guarantees that the
+resultant symbol has an associated script-package. Raises an error if
+the form cannot be compiled to a symbol."
+ (let ((exp (ps-compile-expression form)))
+ (when (eq (first exp) 'js:variable)
+ (setf exp (second exp)))
+ (assert (symbolp exp) ()
+ "~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)
+ exp))
+
+(defmethod ps-compile (form)
+ (error "The object ~S cannot be compiled by ParenScript." form))
+
+(defmethod ps-compile ((form number))
+ form)
+
+(defmethod ps-compile ((form string))
+ form)
+
+(defmethod ps-compile ((form character))
+ (ps-compile (string form)))
+
+(defmethod ps-compile ((symbol symbol))
+ (when (eq *ps-compilation-level* :toplevel)
+ (multiple-value-bind (expansion expanded-p)
+ (ps-macroexpand symbol)
+ (when expanded-p
+ (return-from ps-compile (ps-compile expansion)))))
+ (cond ((keywordp symbol) symbol)
+ ((ps-special-form-p (list symbol))
+ (if (ps-reserved-symbol-p symbol)
+ (funcall (get-ps-special-form symbol))
+ (error "Attempting to use Parenscript special form ~a as variable" symbol)))
+ (t `(js:variable ,symbol))))
+
+;;; operators
+
+(let ((precedence-table (make-hash-table :test 'eq)))
+ (loop for level in '((js:new js:slot-value js:aref)
+ (postfix++ postfix--)
+ (delete void typeof ++ -- unary+ unary- ~ !)
+ (* / %)
+ (+ -)
+ (<< >> >>>)
+ (< > <= >= js:instanceof js:in)
+ (== != === !==)
+ (&)
+ (^)
+ (\|)
+ (\&\& and)
+ (\|\| or)
+ (js:?)
+ (= *= /= %= += -= <<= >>= >>>= \&\= ^= \|=)
+ (comma))
+ for i from 0
+ do (mapcar (lambda (symbol)
+ (setf (gethash symbol precedence-table) i))
+ level))
+ (defun op-precedence (op)
+ (gethash op precedence-table)))
+
+(defun ps-convert-op-name (op)
+ (case op
+ (and '\&\&)
+ (or '\|\|)
+ (not '!)
+ (eql '\=\=)
+ (= '\=\=)
+ (t op)))
+
+(defun maybe-fix-nary-comparison-form (form)
+ (if (< 2 (length (cdr form)))
+ (values
+ (let* ((operator (car form))
+ (tmp-var-forms (butlast (cddr form)))
+ (tmp-vars (loop repeat (length tmp-var-forms)
+ collect (ps-gensym "_cmp")))
+ (all-comparisons (append (list (cadr form))
+ tmp-vars
+ (last form))))
+ `(let ,(mapcar #'list tmp-vars tmp-var-forms)
+ (and ,@(loop for x1 in all-comparisons
+ for x2 in (cdr all-comparisons)
+ collect (list operator x1 x2)))))
+ t)
+ form))
+
+(defun compile-op-form (form)
+ `(js:operator ,(ps-convert-op-name (ps-compile-symbol (car form)))
+ ,@(mapcar (lambda (form)
+ (ps-compile-expression (ps-macroexpand form)))
+ (cdr form))))
+
+(defun compile-funcall-form (form)
+ `(js:funcall
+ ,(ps-compile-expression (if (symbolp (car form))
+ (maybe-rename-local-function (car form))
+ (ps-macroexpand (car form))))
+ ,@(mapcar #'ps-compile-expression (cdr form))))
+
+(defvar compile-expression?)
+
+(defmethod ps-compile ((form cons))
+ (multiple-value-bind (form expanded-p)
+ (ps-macroexpand form)
+ (let ((*ps-compilation-level*
+ (if expanded-p
+ *ps-compilation-level*
+ (adjust-ps-compilation-level form *ps-compilation-level*))))
+ (cond (expanded-p
+ (ps-compile form))
+ ((ps-special-form-p form)
+ (apply (get-ps-special-form (car form)) (cdr form)))
+ ((comparison-form-p form)
+ (multiple-value-bind (form fixed?)
+ (maybe-fix-nary-comparison-form form)
+ (if fixed?
+ (ps-compile form)
+ (compile-op-form form))))
+ ((op-form-p form)
+ (compile-op-form form))
+ ((funcall-form-p form)
+ (compile-funcall-form form))
+ (t (error "Cannot compile ~S to a ParenScript form." form))))))
+
+(defun ps-compile-statement (form)
+ (let ((compile-expression? nil))
+ (ps-compile form)))
+
+(defun ps-compile-expression (form)
+ (let ((compile-expression? t))
+ (ps-compile form)))
+
+(defvar *ps-gensym-counter* 0)
+
+(defun ps-gensym (&optional (prefix "_js"))
+ (let ((prefix (if (stringp prefix) prefix (symbol-to-js-string prefix nil))))
+ (make-symbol (format nil "~A~:[~;_~]~A" prefix
+ (digit-char-p (char prefix (1- (length prefix))))
+ (incf *ps-gensym-counter*)))))
+
+(defmacro with-ps-gensyms (symbols &body body)
+ "Evaluate BODY with SYMBOLS bound to unique ParenScript identifiers.
+
+Each element of SYMBOLS is either a symbol or a list of (symbol
+gensym-prefix-string)."
+ `(let* ,(mapcar (lambda (symbol)
+ (destructuring-bind (symbol &optional prefix)
+ (if (consp symbol)
+ symbol
+ (list symbol))
+ (if prefix
+ `(,symbol (ps-gensym ,prefix))
+ `(,symbol (ps-gensym ,(symbol-to-js-string symbol))))))
+ symbols)
+ ,@body))
+
+(defun %check-once-only-vars (vars)
+ (let ((bad-var (find-if (lambda (x) (or (not (symbolp x)) (keywordp x))) vars)))
+ (when bad-var
+ (error "PS-ONLY-ONCE expected a non-keyword symbol but got ~s" bad-var))))
+
+(defmacro ps-once-only ((&rest vars) &body body)
+ (%check-once-only-vars vars)
+ (let ((gensyms (mapcar (lambda (x) (ps-gensym (string x))) vars)))
+ `(let ,(mapcar (lambda (g v) `(,g (ps-gensym ,(string v)))) gensyms vars)
+ `(let* (,,@(mapcar (lambda (g v) ``(,,g ,,v)) gensyms vars))
+ ,(let ,(mapcar (lambda (g v) `(,v ,g)) gensyms vars)
+ ,@body)))))