;;; -*-lisp-*-
;;;
-;;; $Id$
-;;;
;;; Basic definitions
;;;
;;; (c) 2005 Mark Wooding
(defpackage #:mdw.base
(:use #:common-lisp)
- (:export #:unsigned-fixnum
- #:compile-time-defun
- #:show
- #:stringify #:functionify #:mappend
- #:listify #:fix-pair #:pairify
- #:parse-body #:with-parsed-body
- #:whitespace-char-p
- #:slot-uninitialized
- #:nlet #:while #:until #:case2 #:ecase2 #:setf-default
- #:with-gensyms #:let*/gensyms #:with-places
- #:locp #:locf #:ref #:with-locatives
- #:update-place #:update-place-after
- #:incf-after #:decf-after
- #:fixnump)
#+cmu (:import-from #:extensions #:fixnump))
(in-package #:mdw.base)
;;;--------------------------------------------------------------------------
;;; Useful types.
+(export 'unsigned-fixnum)
(deftype unsigned-fixnum ()
"Unsigned fixnums; useful as array indices and suchlike."
`(mod ,most-positive-fixnum))
;;;--------------------------------------------------------------------------
;;; Some simple macros to get things going.
+(export 'compile-time-defun)
(defmacro compile-time-defun (name args &body body)
"Define a function which can be used by macros during the compilation
process."
`(eval-when (:compile-toplevel :load-toplevel :execute)
(defun ,name ,args ,@body)))
+(export 'show)
(defmacro show (x)
"Debugging tool: print the expression X and its values."
(let ((tmp (gensym)))
(terpri)
(values-list ,tmp))))
+(export 'stringify)
(defun stringify (str)
"Return a string representation of STR. Strings are returned unchanged;
symbols are converted to their names (unqualified!). Other objects are
(symbol (symbol-name str))
(t (princ-to-string str))))
+(export 'functionify)
(defun functionify (func)
"Convert the function-designator FUNC to a function."
(declare (type (or function symbol) func))
(function func)
(symbol (symbol-function func))))
+(export 'mappend)
(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)))
+(export 'listify)
(compile-time-defun listify (x)
"If X is a (possibly empty) list, return X; otherwise return (list X)."
(if (listp x) x (list x)))
((cddr x) (error "Too many elements for a pair."))
(t (values (car x) (cadr x))))))
+(export 'fix-pair)
(compile-time-defun fix-pair (x &optional (y nil defaultp))
"Return two values extracted from X. It works as follows:
(A) -> A, Y
where Y defaults to A if not specified."
(do-fix-pair x y defaultp))
+(export 'pairify)
(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)))
+(export 'whitespace-char-p)
(defun whitespace-char-p (ch)
"Return whether CH is a whitespace character or not."
(case ch
t)
(t nil)))
+(export 'defconstant*)
(defmacro defconstant* (name value &key doc test)
"Define a constant, like `defconstant'. The TEST is an equality test used
to decide whether to override the current definition, if any."
(defconstant ,name ,value ,@(and doc (list doc))))
',name))))
+(export 'slot-uninitialized)
(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."))
+(export 'parse-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
(and decls (list (cons 'declare decls)))
forms))))))))
+(export 'with-parsed-body)
(defmacro with-parsed-body
((bodyvar declvar &optional (docvar (gensym) docp)) form &body body)
"Parse FORM into a body, declarations and (maybe) a docstring; bind BODYVAR
,@(if docp nil `((declare (ignore ,docvar))))
,@body))
+(export 'fixnump)
#-cmu
(progn
(declaim (inline fixnump))
;;;--------------------------------------------------------------------------
;;; Generating symbols.
+(export 'symbolicate)
+(defun symbolicate (&rest names)
+ "Return a symbol constructued by concatenating the NAMES.
+
+ The NAMES are coerced to strings, using the `string' function, so they may
+ be strings, characters, or symbols. The resulting symbol is interned in
+ the current `*package*'."
+ (intern (apply #'concatenate 'string (mapcar #'string names))))
+
+(export 'with-gensyms)
(defmacro with-gensyms (syms &body body)
"Everyone's favourite macro helper."
`(let (,@(mapcar (lambda (sym) `(,sym (gensym ,(symbol-name sym))))
(listify syms)))
,@body))
+(export 'let*/gensyms)
(defmacro let*/gensyms (binds &body body)
"A macro helper. BINDS is a list of binding pairs (VAR VALUE), where VALUE
defaults to VAR. The result is that BODY is evaluated in a context where
(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)) (progn ,@body)))
-
-(defmacro until (cond &body body)
- "If COND is true, evaluate to nil; otherwise evaluate BODY and try again."
- `(loop (when ,cond (return)) (progn ,@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 varx vary) &rest forms)
- clause
- `(,cases
- ,@(if varx
- (list `(let ((,(or vary varx) ,argument)
- ,@(and vary
- `((,varx ,scrutinee))))
- ,@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 ([[SCRUVAR] ARGVAR]) 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 ARGVAR bound to the ARGUMENT and SCRUVAR bound to
- the SCRUTINEE (where specified). Note the bizarre defaulting behaviour:
- ARGVAR is less optional than SCRUVAR."
- (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))
-
-(defmacro setf-default (&rest specs &environment env)
- "Like setf, but only sets places which are currently nil.
-
- The arguments are an alternating list of PLACEs and DEFAULTs. If a PLACE
- is nil, the DEFAULT is evaluated and stored in the PLACE; otherwise the
- default is /not/ stored. The result is the (new) value of the last
- PLACE."
- (labels ((doit (specs)
- (cond ((null specs) nil)
- ((null (cdr specs))
- (error "Odd number of arguments for SETF-DEFAULT."))
- (t
- (let ((place (car specs))
- (default (cadr specs))
- (rest (cddr specs)))
- (multiple-value-bind
- (vars vals store-vals writer reader)
- (get-setf-expansion place env)
- `(let* ,(mapcar #'list vars vals)
- (or ,reader
- (multiple-value-bind ,store-vals ,default
- ,writer))
- ,@(and rest (list (doit rest))))))))))
- (doit specs)))
-
-;;;--------------------------------------------------------------------------
;;; Capturing places as symbols.
(defmacro %place-ref (getform setform newtmp)
"Grim helper macro for with-places."
(values nil nil newtmp setform getform))
+(export 'with-places)
(defmacro with-places (clauses &body body &environment env)
"Define symbols which refer to `setf'-able places.
(symbol-macrolet (,@(nreverse macro-binds))
,@body))))
+(export 'with-places/gensyms)
(defmacro with-places/gensyms (clauses &body body)
"A kind of a cross between `with-places' and `let*/gensyms'.
,@body))))
;;;--------------------------------------------------------------------------
+;;; Some simple yet useful control structures.
+
+(export 'nlet)
+(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))))
+
+(export 'while)
+(defmacro while (cond &body body)
+ "If COND is false, evaluate to nil; otherwise evaluate BODY and try again."
+ `(loop (unless ,cond (return)) (progn ,@body)))
+
+(export 'until)
+(defmacro until (cond &body body)
+ "If COND is true, evaluate to nil; otherwise evaluate BODY and try again."
+ `(loop (when ,cond (return)) (progn ,@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 varx vary) &rest forms)
+ clause
+ `(,cases
+ ,@(if varx
+ (list `(let ((,(or vary varx) ,argument)
+ ,@(and vary
+ `((,varx ,scrutinee))))
+ ,@forms))
+ forms))))
+ clauses)))))
+
+(export 'caase2)
+(defmacro case2 (vform &body clauses)
+ "VFORM is a form which evaluates to two values, SCRUTINEE and ARGUMENT.
+ The CLAUSES have the form (CASES ([[SCRUVAR] ARGVAR]) 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 ARGVAR bound to the ARGUMENT and SCRUVAR bound to
+ the SCRUTINEE (where specified). Note the bizarre defaulting behaviour:
+ ARGVAR is less optional than SCRUVAR."
+ (do-case2-like 'case vform clauses))
+
+(export 'ecase2)
+(defmacro ecase2 (vform &body clauses)
+ "Like `case2', but signals an error if no clause matches the SCRUTINEE."
+ (do-case2-like 'ecase vform clauses))
+
+(export 'setf-default)
+(defmacro setf-default (&rest specs)
+ "Like setf, but only sets places which are currently nil.
+
+ The arguments are an alternating list of PLACEs and DEFAULTs. If a PLACE
+ is nil, the DEFAULT is evaluated and stored in the PLACE; otherwise the
+ default is /not/ stored. The result is the (new) value of the last
+ PLACE."
+ `(progn ,@(do ((list nil)
+ (specs specs (cddr specs)))
+ ((endp specs) (nreverse list))
+ (unless (cdr specs)
+ (error "Odd number of arguments for `setf-default'."))
+ (push (with-places/gensyms ((place (car specs)))
+ `(or ,place (setf ,place ,(cadr specs))))
+ list))))
+
+;;;--------------------------------------------------------------------------
;;; Update-in-place macros built using with-places.
+(export 'update-place)
(defmacro update-place (op place &rest args)
"Update PLACE with (OP PLACE . ARGS), returning the new value."
(with-places/gensyms (place)
`(setf ,place (,op ,place ,@args))))
+(export 'update-place-after)
(defmacro update-place-after (op place &rest args)
"Update PLACE with (OP PLACE . ARGS), returning the old value."
(with-places/gensyms (place)
(setf ,place (,op ,x ,@args))
,x))))
+(export 'incf-after)
(defmacro incf-after (place &optional (by 1))
"Increment PLACE by BY, returning the old value."
`(update-place-after + ,place ,by))
+(export 'decf-after)
(defmacro decf-after (place &optional (by 1))
"Decrement PLACE by BY, returning the old value."
`(update-place-after - ,place ,by))
;;;--------------------------------------------------------------------------
;;; Locatives.
+(export 'locp)
(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))
+ (reader (slot-uninitialized) :type function :read-only t)
+ (writer (slot-uninitialized) :type function :read-only t))
+(export 'locf)
(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
(make-loc (lambda () ,getform)
(lambda (,@newtmps) ,setform)))))
+(export 'ref)
(declaim (inline ref (setf ref)))
-
(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))
+(export 'with-locatives)
(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
~mdw / lisp / blobdiff