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Diffstat (limited to 'third_party/lisp/fiveam/src/utils.lisp')
| -rw-r--r-- | third_party/lisp/fiveam/src/utils.lisp | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/third_party/lisp/fiveam/src/utils.lisp b/third_party/lisp/fiveam/src/utils.lisp new file mode 100644 index 000000000000..49d552fa000e --- /dev/null +++ b/third_party/lisp/fiveam/src/utils.lisp @@ -0,0 +1,226 @@ +;;;; -*- Mode: Lisp; indent-tabs-mode: nil -*- + +(in-package :it.bese.fiveam) + +(defmacro dolist* ((iterator list &optional return-value) &body body) + "Like DOLIST but destructuring-binds the elements of LIST. + +If ITERATOR is a symbol then dolist* is just like dolist EXCEPT +that it creates a fresh binding." + (if (listp iterator) + (let ((i (gensym "DOLIST*-I-"))) + `(dolist (,i ,list ,return-value) + (destructuring-bind ,iterator ,i + ,@body))) + `(dolist (,iterator ,list ,return-value) + (let ((,iterator ,iterator)) + ,@body)))) + +(defun make-collector (&optional initial-value) + "Create a collector function. + +A Collector function will collect, into a list, all the values +passed to it in the order in which they were passed. If the +callector function is called without arguments it returns the +current list of values." + (let ((value initial-value) + (cdr (last initial-value))) + (lambda (&rest items) + (if items + (progn + (if value + (if cdr + (setf (cdr cdr) items + cdr (last items)) + (setf cdr (last items))) + (setf value items + cdr (last items))) + items) + value)))) + +(defun partitionx (list &rest lambdas) + (let ((collectors (mapcar (lambda (l) + (cons (if (and (symbolp l) + (member l (list :otherwise t) + :test #'string=)) + (constantly t) + l) + (make-collector))) + lambdas))) + (dolist (item list) + (block item + (dolist* ((test-func . collector-func) collectors) + (when (funcall test-func item) + (funcall collector-func item) + (return-from item))))) + (mapcar #'funcall (mapcar #'cdr collectors)))) + +;;;; ** Anaphoric conditionals + +(defmacro if-bind (var test &body then/else) + "Anaphoric IF control structure. + +VAR (a symbol) will be bound to the primary value of TEST. If +TEST returns a true value then THEN will be executed, otherwise +ELSE will be executed." + (assert (first then/else) + (then/else) + "IF-BIND missing THEN clause.") + (destructuring-bind (then &optional else) + then/else + `(let ((,var ,test)) + (if ,var ,then ,else)))) + +(defmacro aif (test then &optional else) + "Just like IF-BIND but the var is always IT." + `(if-bind it ,test ,then ,else)) + +;;;; ** Simple list matching based on code from Paul Graham's On Lisp. + +(defmacro acond2 (&rest clauses) + (if (null clauses) + nil + (with-gensyms (val foundp) + (destructuring-bind ((test &rest progn) &rest others) + clauses + `(multiple-value-bind (,val ,foundp) + ,test + (if (or ,val ,foundp) + (let ((it ,val)) + (declare (ignorable it)) + ,@progn) + (acond2 ,@others))))))) + +(defun varsymp (x) + (and (symbolp x) + (let ((name (symbol-name x))) + (and (>= (length name) 2) + (char= (char name 0) #\?))))) + +(defun binding (x binds) + (labels ((recbind (x binds) + (aif (assoc x binds) + (or (recbind (cdr it) binds) + it)))) + (let ((b (recbind x binds))) + (values (cdr b) b)))) + +(defun list-match (x y &optional binds) + (acond2 + ((or (eql x y) (eql x '_) (eql y '_)) + (values binds t)) + ((binding x binds) (list-match it y binds)) + ((binding y binds) (list-match x it binds)) + ((varsymp x) (values (cons (cons x y) binds) t)) + ((varsymp y) (values (cons (cons y x) binds) t)) + ((and (consp x) (consp y) (list-match (car x) (car y) binds)) + (list-match (cdr x) (cdr y) it)) + (t (values nil nil)))) + +(defun vars (match-spec) + (let ((vars nil)) + (labels ((find-vars (spec) + (cond + ((null spec) nil) + ((varsymp spec) (push spec vars)) + ((consp spec) + (find-vars (car spec)) + (find-vars (cdr spec)))))) + (find-vars match-spec)) + (delete-duplicates vars))) + +(defmacro list-match-case (target &body clauses) + (if clauses + (destructuring-bind ((test &rest progn) &rest others) + clauses + (with-gensyms (tgt binds success) + `(let ((,tgt ,target)) + (multiple-value-bind (,binds ,success) + (list-match ,tgt ',test) + (declare (ignorable ,binds)) + (if ,success + (let ,(mapcar (lambda (var) + `(,var (cdr (assoc ',var ,binds)))) + (vars test)) + (declare (ignorable ,@(vars test))) + ,@progn) + (list-match-case ,tgt ,@others)))))) + nil)) + +;;;; * def-special-environment + +(defun check-required (name vars required) + (dolist (var required) + (assert (member var vars) + (var) + "Unrecognized symbol ~S in ~S." var name))) + +(defmacro def-special-environment (name (&key accessor binder binder*) + &rest vars) + "Define two macros for dealing with groups or related special variables. + +ACCESSOR is defined as a macro: (defmacro ACCESSOR (VARS &rest +BODY)). Each element of VARS will be bound to the +current (dynamic) value of the special variable. + +BINDER is defined as a macro for introducing (and binding new) +special variables. It is basically a readable LET form with the +prorpe declarations appended to the body. The first argument to +BINDER must be a form suitable as the first argument to LET. + +ACCESSOR defaults to a new symbol in the same package as NAME +which is the concatenation of \"WITH-\" NAME. BINDER is built as +\"BIND-\" and BINDER* is BINDER \"*\"." + (unless accessor + (setf accessor (format-symbol (symbol-package name) "~A-~A" '#:with name))) + (unless binder + (setf binder (format-symbol (symbol-package name) "~A-~A" '#:bind name))) + (unless binder* + (setf binder* (format-symbol (symbol-package binder) "~A~A" binder '#:*))) + `(eval-when (:compile-toplevel :load-toplevel :execute) + (flet () + (defmacro ,binder (requested-vars &body body) + (check-required ',name ',vars (mapcar #'car requested-vars)) + `(let ,requested-vars + (declare (special ,@(mapcar #'car requested-vars))) + ,@body)) + (defmacro ,binder* (requested-vars &body body) + (check-required ',name ',vars (mapcar #'car requested-vars)) + `(let* ,requested-vars + (declare (special ,@(mapcar #'car requested-vars))) + ,@body)) + (defmacro ,accessor (requested-vars &body body) + (check-required ',name ',vars requested-vars) + `(locally (declare (special ,@requested-vars)) + ,@body)) + ',name))) + +;; Copyright (c) 2002-2006, Edward Marco Baringer +;; All rights reserved. +;; +;; Redistribution and use in source and binary forms, with or without +;; modification, are permitted provided that the following conditions are +;; met: +;; +;; - Redistributions of source code must retain the above copyright +;; notice, this list of conditions and the following disclaimer. +;; +;; - Redistributions in binary form must reproduce the above copyright +;; notice, this list of conditions and the following disclaimer in the +;; documentation and/or other materials provided with the distribution. +;; +;; - Neither the name of Edward Marco Baringer, nor BESE, nor the names +;; of its contributors may be used to endorse or promote products +;; derived from this software without specific prior written permission. +;; +;; THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +;; "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +;; LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +;; A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +;; OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +;; SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +;; LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +;; DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +;; THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +;; (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +;; OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE |