collect, unix: Rename `mdw.collect' package to just `collect'.

[lisp] / mdw-base.lisp

diff --git a/mdw-base.lisp b/mdw-base.lisp
index 21948fa..bbe7662 100644 (file)
--- a/mdw-base.lisp
+++ b/mdw-base.lisp
@@ -23,6 +23,9 @@
 ;;; along with this program; if not, write to the Free Software Foundation,
 ;;; Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 
 ;;; along with this program; if not, write to the Free Software Foundation,
 ;;; Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 

+;;;--------------------------------------------------------------------------
+;;; Package things.
+

 (defpackage #:mdw.base
   (:use #:common-lisp)
   (:export #:compile-time-defun
 (defpackage #:mdw.base
   (:use #:common-lisp)
   (:export #:compile-time-defun


@@ -30,12 +33,16 @@
           #:stringify #:listify #:fix-pair #:pairify
           #:whitespace-char-p
           #:slot-uninitialized
           #:stringify #:listify #:fix-pair #:pairify
           #: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))
 (in-package #:mdw.base)
 
           #:with-gensyms #:let*/gensyms #:with-places
           #:locp #:locf #:ref #:with-locatives
           #:update-place #:update-place-after
           #:incf-after #:decf-after))
 (in-package #:mdw.base)
 

+;;;--------------------------------------------------------------------------
+;;; Some simple macros to get things going.
+

 (defmacro compile-time-defun (name args &body body)
   "Define a function which can be used by macros during the compilation
 process."
 (defmacro compile-time-defun (name args &body body)
   "Define a function which can be used by macros during the compilation
 process."


@@ -58,9 +65,11 @@ converted to their print representations."
     (symbol (symbol-name str))
     (t (with-output-to-string (s)
         (princ str s)))))
     (symbol (symbol-name str))
     (t (with-output-to-string (s)
         (princ str s)))))

+

 (compile-time-defun listify (x)
   "If X is a (possibly empty) list, return X; otherwise return (list X)."
   (if (listp x) x (list x)))
 (compile-time-defun listify (x)
   "If X is a (possibly empty) list, return X; otherwise return (list X)."
   (if (listp x) x (list x)))

+

 (compile-time-defun do-fix-pair (x y defaultp)
   "Helper function for fix-pair and pairify."
   (flet ((singleton (x) (values x (if defaultp y x))))
 (compile-time-defun do-fix-pair (x y defaultp)
   "Helper function for fix-pair and pairify."
   (flet ((singleton (x) (values x (if defaultp y x))))


@@ -69,6 +78,7 @@ converted to their print representations."
          ((atom (cdr x)) (values (car x) (cdr x)))
          ((cddr x) (error "Too many elements for a pair."))
          (t (values (car x) (cadr x))))))
          ((atom (cdr x)) (values (car x) (cdr x)))
          ((cddr x) (error "Too many elements for a pair."))
          (t (values (car x) (cadr x))))))

+

 (compile-time-defun fix-pair (x &optional (y nil defaultp))
   "Return two values extracted from X.  It works as follows:
   (A) -> A, Y
 (compile-time-defun fix-pair (x &optional (y nil defaultp))
   "Return two values extracted from X.  It works as follows:
   (A) -> A, Y


@@ -78,6 +88,7 @@ converted to their print representations."
   A -> A, Y
 where Y defaults to A if not specified."
   (do-fix-pair x y defaultp))
   A -> A, Y
 where Y defaults to A if not specified."
   (do-fix-pair x y defaultp))

+

 (compile-time-defun pairify (x &optional (y nil defaultp))
   "As for fix-pair, but returns a list instead of two values."
   (multiple-value-call #'list (do-fix-pair x y defaultp)))
 (compile-time-defun pairify (x &optional (y nil defaultp))
   "As for fix-pair, but returns a list instead of two values."
   (multiple-value-call #'list (do-fix-pair x y defaultp)))


@@ -88,30 +99,15 @@ where Y defaults to A if not specified."
     ((#\space #\tab #\newline #\return #\vt #\formfeed) t)
     (t nil)))
 
     ((#\space #\tab #\newline #\return #\vt #\formfeed) t)
     (t nil)))
 

-(defmacro nlet (name binds &body body)
-  "Scheme's named let."
-  (multiple-value-bind (vars vals)
-      (loop for bind in binds
-           for (var val) = (pairify bind nil)
-           collect var into vars
-           collect val into vals
-           finally (return (values vars vals)))
-    `(labels ((,name ,vars
-               ,@body))
-       (,name ,@vals))))
-
-(defmacro while (cond &body body)
-  "If COND is false, evaluate to nil; otherwise evaluate BODY and try again."
-  `(loop
-     (unless `cond (return))
-     ,@body))
-

 (declaim (ftype (function nil ()) slot-unitialized))
 (defun slot-uninitialized ()
   "A function which signals an error.  Can be used as an initializer form in
 structure definitions without doom ensuing."
   (error "No initializer for slot."))
 
 (declaim (ftype (function nil ()) slot-unitialized))
 (defun slot-uninitialized ()
   "A function which signals an error.  Can be used as an initializer form in
 structure definitions without doom ensuing."
   (error "No initializer for slot."))
 

+;;;--------------------------------------------------------------------------
+;;; Generating symbols.
+

 (defmacro with-gensyms (syms &body body)
   "Everyone's favourite macro helper."
   `(let (,@(mapcar (lambda (sym) `(,sym (gensym ,(symbol-name sym))))
 (defmacro with-gensyms (syms &body body)
   "Everyone's favourite macro helper."
   `(let (,@(mapcar (lambda (sym) `(,sym (gensym ,(symbol-name sym))))


@@ -135,13 +131,68 @@ gensyms will be bound to the corresponding VALUE."
         `(progn ,@body)
         (car (more (mapcar #'pairify (listify binds)))))))
 
         `(progn ,@body)
         (car (more (mapcar #'pairify (listify binds)))))))
 

+;;;--------------------------------------------------------------------------
+;;; Some simple yet useful control structures.
+
+(defmacro nlet (name binds &body body)
+  "Scheme's named let."
+  (multiple-value-bind (vars vals)
+      (loop for bind in binds
+           for (var val) = (pairify bind nil)
+           collect var into vars
+           collect val into vals
+           finally (return (values vars vals)))
+    `(labels ((,name ,vars
+               ,@body))
+       (,name ,@vals))))
+
+(defmacro while (cond &body body)
+  "If COND is false, evaluate to nil; otherwise evaluate BODY and try again."
+  `(loop
+     (unless ,cond (return))
+     ,@body))
+
+(compile-time-defun do-case2-like (kind vform clauses)
+  "Helper function for `case2' and `ecase2'."
+  (with-gensyms (scrutinee argument)
+    `(multiple-value-bind (,scrutinee ,argument) ,vform
+       (declare (ignorable ,argument))
+       (,kind ,scrutinee
+        ,@(mapcar (lambda (clause)
+                    (destructuring-bind
+                        (cases (&optional var) &rest forms)
+                        clause
+                      `(,cases
+                        ,@(if var
+                              (list `(let ((,var ,argument)) ,@forms))
+                              forms))))
+                  clauses)))))
+
+(defmacro case2 (vform &body clauses)
+  "VFORM is a form which evaluates to two values, SCRUTINEE and ARGUMENT.
+The CLAUSES have the form (CASES ([VAR]) FORMS...), where a standard `case'
+clause has the form (CASES FORMS...).  The `case2' form evaluates the VFORM,
+and compares the SCRUTINEE to the various CASES, in order, just like `case'.
+If there is a match, then the corresponding FORMs are evaluated with VAR (if
+specified) bound to the value of ARGUMENT."
+  (do-case2-like 'case vform clauses))
+
+(defmacro ecase2 (vform &body clauses)
+  "Like `case2', but signals an error if no clause matches the SCRUTINEE."
+  (do-case2-like 'ecase vform clauses))
+
+;;;--------------------------------------------------------------------------
+;;; with-places
+

 (defmacro %place-ref (getform setform newtmp)
   "Grim helper macro for with-places."
   (declare (ignore setform newtmp))
   getform)
 (defmacro %place-ref (getform setform newtmp)
   "Grim helper macro for with-places."
   (declare (ignore setform newtmp))
   getform)

+

 (define-setf-expander %place-ref (getform setform newtmp)
   "Grim helper macro for with-places."
   (values nil nil newtmp setform getform))
 (define-setf-expander %place-ref (getform setform newtmp)
   "Grim helper macro for with-places."
   (values nil nil newtmp setform getform))

+

 (defmacro with-places ((&key environment) places &body body)
   "A hairy helper, for writing setf-like macros.  PLACES is a list of binding
 pairs (VAR PLACE), where PLACE defaults to VAR.  The result is that BODY is
 (defmacro with-places ((&key environment) places &body body)
   "A hairy helper, for writing setf-like macros.  PLACES is a list of binding
 pairs (VAR PLACE), where PLACE defaults to VAR.  The result is that BODY is


@@ -175,29 +226,38 @@ reading or setting the value of the corresponding PLACE."
                                          body))))))))))
           (car (more (mapcar #'pairify (listify places))))))))
 
                                          body))))))))))
           (car (more (mapcar #'pairify (listify places))))))))
 

+;;;--------------------------------------------------------------------------
+;;; Update-in-place macros built using with-places.
+

 (defmacro update-place (op place arg &environment env)
   "Update PLACE with the value of OP PLACE ARG, returning the new value."
   (with-places (:environment env) (place)
     `(setf ,place (,op ,place ,arg))))
 (defmacro update-place (op place arg &environment env)
   "Update PLACE with the value of OP PLACE ARG, returning the new value."
   (with-places (:environment env) (place)
     `(setf ,place (,op ,place ,arg))))

+

 (defmacro update-place-after (op place arg &environment env)
   "Update PLACE with the value of OP PLACE ARG, returning the old value."
   (with-places (:environment env) (place)
     (with-gensyms (x)
       `(let ((,x ,place))
 (defmacro update-place-after (op place arg &environment env)
   "Update PLACE with the value of OP PLACE ARG, returning the old value."
   (with-places (:environment env) (place)
     (with-gensyms (x)
       `(let ((,x ,place))

-         (setf ,place (,op ,x ,arg))
-         ,x))))
+        (setf ,place (,op ,x ,arg))
+        ,x))))
+

 (defmacro incf-after (place &optional (by 1))
   "Increment PLACE by BY, returning the old value."
   `(update-place-after + ,place ,by))
 (defmacro incf-after (place &optional (by 1))
   "Increment PLACE by BY, returning the old value."
   `(update-place-after + ,place ,by))

+

 (defmacro decf-after (place &optional (by 1))
   "Decrement PLACE by BY, returning the old value."
   `(update-place-after - ,place ,by))
 
 (defmacro decf-after (place &optional (by 1))
   "Decrement PLACE by BY, returning the old value."
   `(update-place-after - ,place ,by))
 

+;;;--------------------------------------------------------------------------
+;;; Locatives.

 
 (defstruct (loc (:predicate locp) (:constructor make-loc (reader writer)))
   "Locative data type.  See `locf' and `ref'."
   (reader (slot-uninitialized) :type function)
   (writer (slot-uninitialized) :type function))
 
 (defstruct (loc (:predicate locp) (:constructor make-loc (reader writer)))
   "Locative data type.  See `locf' and `ref'."
   (reader (slot-uninitialized) :type function)
   (writer (slot-uninitialized) :type function))

+

 (defmacro locf (place &environment env)
   "Slightly cheesy locatives.  (locf PLACE) returns an object which, using
 the `ref' function, can be used to read or set the value of PLACE.  It's
 (defmacro locf (place &environment env)
   "Slightly cheesy locatives.  (locf PLACE) returns an object which, using
 the `ref' function, can be used to read or set the value of PLACE.  It's


@@ -210,13 +270,17 @@ work."
     `(let* (,@(mapcar #'list valtmps valforms))
        (make-loc (lambda () ,getform)
                  (lambda (,@newtmps) ,setform)))))
     `(let* (,@(mapcar #'list valtmps valforms))
        (make-loc (lambda () ,getform)
                  (lambda (,@newtmps) ,setform)))))

+

 (declaim (inline loc (setf loc)))
 (declaim (inline loc (setf loc)))

+

 (defun ref (loc)
   "Fetch the value referred to by a locative."
   (funcall (loc-reader loc)))
 (defun ref (loc)
   "Fetch the value referred to by a locative."
   (funcall (loc-reader loc)))

+

 (defun (setf ref) (new loc)
   "Store a new value in the place referred to by a locative."
   (funcall (loc-writer loc) new))
 (defun (setf ref) (new loc)
   "Store a new value in the place referred to by a locative."
   (funcall (loc-writer loc) new))

+

 (defmacro with-locatives (locs &body body)
   "LOCS is a list of items of the form (SYM [LOC-EXPR]), where SYM is a
 symbol and LOC-EXPR evaluates to a locative.  If LOC-EXPR is omitted, it
 (defmacro with-locatives (locs &body body)
   "LOCS is a list of items of the form (SYM [LOC-EXPR]), where SYM is a
 symbol and LOC-EXPR evaluates to a locative.  If LOC-EXPR is omitted, it