mop: Handy function for making modified copies of instances.

[lisp] / mdw-base.lisp

diff --git a/mdw-base.lisp b/mdw-base.lisp
index 6b235f57c5bc77ba2af1013342c38242ccedc479..59ea6923c65b086de015750cc134e51e6ab4101b 100644 (file)
--- a/mdw-base.lisp
+++ b/mdw-base.lisp
@@ -30,14 +30,17 @@ (defpackage #:mdw.base
   (:use #:common-lisp)
   (:export #:compile-time-defun
           #:show
-          #:stringify #:listify #:fix-pair #:pairify #:parse-body
+          #:stringify #:mappend #:listify #:fix-pair #:pairify #:parse-body
           #:whitespace-char-p
           #:slot-uninitialized
           #:nlet #:while #:case2 #:ecase2
           #:with-gensyms #:let*/gensyms #:with-places
           #:locp #:locf #:ref #:with-locatives
           #:update-place #:update-place-after
-          #:incf-after #:decf-after))
+          #:incf-after #:decf-after
+          #:fixnump)
+  #+cmu (:import-from #:extensions #:fixnump))
+
 (in-package #:mdw.base)
 
 ;;;--------------------------------------------------------------------------
@@ -66,6 +69,12 @@ (defun stringify (str)
     (t (with-output-to-string (s)
         (princ str s)))))
 
+(defun mappend (function list &rest more-lists)
+  "Apply FUNCTION to corresponding elements of LIST and MORE-LISTS, yielding
+   a list.  Return the concatenation of all the resulting lists.  Like
+   mapcan, but nondestructive."
+  (apply #'append (apply #'mapcar function list more-lists)))
+
 (compile-time-defun listify (x)
   "If X is a (possibly empty) list, return X; otherwise return (list X)."
   (if (listp x) x (list x)))
@@ -105,24 +114,31 @@ (defun slot-uninitialized ()
    structure definitions without doom ensuing."
   (error "No initializer for slot."))
 
-(compile-time-defun parse-body (body)
+(compile-time-defun parse-body (body &key (allow-docstring-p t))
   "Given a BODY (a list of forms), parses it into three sections: a
    docstring, a list of declarations (forms beginning with the symbol
    `declare') and the body forms.  The result is returned as three lists
    (even the docstring), suitable for interpolation into a backquoted list
-   using `@,'."
-  (multiple-value-bind
-      (doc body)
-      (if (and (consp body)
-              (stringp (car body)))
-         (values (list (car body)) (cdr body))
-         (values nil body))
-    (loop for forms on body
-         for form = (car forms)
-         while (and (consp form)
-                    (eq (car form) 'declare))
-         collect form into decls
-         finally (return (values doc decls forms)))))
+   using `@,'.  If ALLOW-DOCSTRING-P is nil, docstrings aren't allowed at
+   all."
+  (let ((doc nil) (decls nil))
+    (do ((forms body (cdr forms))) (nil)
+      (let ((form (and forms (car forms))))
+       (cond ((and allow-docstring-p (not doc) (stringp form) (cdr forms))
+              (setf doc form))
+             ((and (consp form)
+                   (eq (car form) 'declare))
+              (setf decls (append decls (cdr form))))
+             (t (return (values (and doc (list doc))
+                                (and decls (list (cons 'declare decls)))
+                                forms))))))))
+
+#-cmu
+(progn
+  (declaim (inline fixnump))
+  (defun fixnump (object)
+    "Answer non-nil if OBJECT is a fixnum, or nil if it isn't."
+    (typep object 'fixnum)))
 
 ;;;--------------------------------------------------------------------------
 ;;; Generating symbols.