Implement dynamic calling and fix `bind!`
It turns out `bind!` needs to actually *copy* the thing it's binding into the
target, not create a reference.
Dynamic calling was actually pretty easy.
| author |
Steve Losh <steve@stevelosh.com> |
| date |
Wed, 29 Jun 2016 16:42:02 +0000 |
| parents |
72bbdd515725 |
| children |
970e21fa14b0 |
(in-package #:bones.utils)
(defmacro push-if-new (thing place
&environment env
&key key (test '#'eql))
"Push `thing` into the list at `place` if it's not already there.
Returns whether `thing` was actually pushed. This function is basically
`pushnew` except for the return value.
"
(multiple-value-bind (temps exprs stores store-expr access-expr)
(get-setf-expansion place env)
(declare (ignore stores store-expr))
(with-gensyms (current result)
`(let* (,@(zip temps exprs)
(,current ,access-expr)
(,result (pushnew ,thing ,place :key ,key :test ,test)))
(not (eql ,current ,result))))))
(defun invert-hash-table (ht)
"Jesus christ don't actually use this for anything but debugging.
Inverts the keys/values of a hash table.
"
(alist-to-hash-table
(loop :for k :being :the :hash-keys :of ht
:using (hash-value v)
:collect (list v k))))
(defmacro repeat (n &body body)
"Repeat `body` `n` times."
`(dotimes (,(gensym) ,n)
,@body))
(defun hex (d)
(format nil "~X" d))
(defmacro when-let ((symbol value) &body body)
`(let ((,symbol ,value))
(when ,symbol ,@body)))
;;;; loop/recur
(defmacro recursively (bindings &body body)
"Execute body recursively, like Clojure's `loop`/`recur`.
`bindings` should contain a list of symbols and (optional) default values.
In `body`, `recur` will be bound to the function for recurring.
Example:
(defun length (some-list)
(recursively ((list some-list) (n 0))
(if (null list)
n
(recur (cdr list) (1+ n)))))
"
(flet ((extract-var (binding)
(if (atom binding) binding (first binding)))
(extract-val (binding)
(if (atom binding) nil (second binding))))
`(labels ((recur ,(mapcar #'extract-var bindings)
,@body))
(recur ,@(mapcar #'extract-val bindings)))))