Defstruct copier function

[jscl.git] / ecmalisp.lisp

diff --git a/ecmalisp.lisp b/ecmalisp.lisp
index bbc6340..bf4810b 100644 (file)
--- a/ecmalisp.lisp
+++ b/ecmalisp.lisp
@@ -383,6 +383,61 @@
            ,@body)
          (cdr ,head))))
 
+  ;; A very simple defstruct built on lists. It supports just slot with
+  ;; an optional default initform, and it will create a constructor,
+  ;; predicate and accessors for you.
+  (defmacro defstruct (name &rest slots)
+    (unless (symbolp name)
+      (error "It is not a full defstruct implementation."))
+    (let* ((name-string (symbol-name name))
+           (slot-descriptions
+            (mapcar (lambda (sd)
+                      (cond
+                        ((symbolp sd)
+                         (list sd))
+                        ((and (listp sd) (car sd) (cddr sd))
+                         sd)
+                        (t
+                         (error "Bad slot accessor."))))
+                    slots))
+           (predicate (intern (concat name-string "P"))))
+      `(progn
+         ;; Constructor
+         (defun ,(intern (concat "MAKE-" name-string)) (&key ,@slot-descriptions)
+           (list ',name ,@(mapcar #'car slot-descriptions)))
+         ;; Predicate
+         (defun ,predicate (x)
+           (and (consp x) (eq (car x) ',name)))
+         ;; Copier
+         (defun ,(intern (concat "COPY-" name-string)) (x)
+           (copy-list x))
+         ;; Slot accessors
+         ,@(with-collect
+            (let ((index 1))
+              (dolist (slot slot-descriptions)
+                (let* ((name (car slot))
+                       (accessor-name (intern (concat name-string "-" (string name)))))
+                  (collect
+                      `(defun ,accessor-name (x)
+                           (unless (,predicate x)
+                             (error ,(concat "The object is not a type " name-string)))
+                         (nth ,index x)))
+                  ;; TODO: Implement this with a higher level
+                  ;; abstraction like defsetf or (defun (setf ..))
+                  (collect
+                      `(define-setf-expander ,accessor-name (x)
+                         (let ((object (gensym))
+                               (new-value (gensym)))
+                           (values (list object)
+                                   (list x)
+                                   (list new-value)
+                                   `(progn
+                                      (rplaca (nthcdr ,',index ,object) ,new-value) 
+                                      ,new-value)
+                                   `(,',accessor-name ,object)))))
+                  (incf index)))))
+         ',name)))
+
   (defun map1 (func list)
     (with-collect
         (while list
@@ -533,6 +588,14 @@
         (return-from every nil)))
     t)
 
+  (defun position (elt sequence)
+    (let ((pos 0))
+      (do-sequence (x seq)
+        (when (eq elt x)
+          (return))
+        (incf pos))
+      pos))
+
   (defun assoc (x alist)
     (while alist
       (if (eql x (caar alist))
@@ -958,7 +1021,9 @@
                        "()"
                        (prin1-to-string (vector-to-list form)))))
       ((packagep form)
-       (concat "#<PACKAGE " (package-name form) ">"))))
+       (concat "#<PACKAGE " (package-name form) ">"))
+      (t
+       (concat "#<javascript object>"))))
 
   (defun write-line (x)
     (write-string x)
@@ -2712,6 +2777,14 @@
       (t
        (error (concat "How should I compile " (prin1-to-string sexp) "?"))))))
 
+
+(defvar *compile-print-toplevels* nil)
+
+(defun truncate-string (string &optional (width 60))
+  (let ((n (or (position #\newline string)
+               (min width (length string)))))
+    (subseq string 0 n)))
+
 (defun ls-compile-toplevel (sexp &optional multiple-value-p)
   (let ((*toplevel-compilations* nil))
     (cond
@@ -2721,6 +2794,12 @@
                            (cdr sexp))))
          (join (remove-if #'null-or-empty-p subs))))
       (t
+       (when *compile-print-toplevels*
+         (let ((form-string (prin1-to-string sexp)))
+           (write-string "Compiling ")
+           (write-string (truncate-string form-string))
+           (write-line "...")))
+       
        (let ((code (ls-compile sexp multiple-value-p)))
          (code (join-trailing (get-toplevel-compilations)
                               (code ";" *newline*))
@@ -2804,8 +2883,9 @@
         (read-sequence seq in)
         seq)))
 
-  (defun ls-compile-file (filename output)
-    (let ((*compiling-file* t))
+  (defun ls-compile-file (filename output &key print)
+    (let ((*compiling-file* t)
+          (*compile-print-toplevels* print))
       (with-open-file (out output :direction :output :if-exists :supersede)
         (write-string (read-whole-file "prelude.js") out)
         (let* ((source (read-whole-file filename))
@@ -2824,4 +2904,4 @@
           *gensym-counter* 0
           *literal-counter* 0
           *block-counter* 0)
-    (ls-compile-file "ecmalisp.lisp" "ecmalisp.js")))
+    (ls-compile-file "ecmalisp.lisp" "ecmalisp.js" :print t)))