Add a REAL janky result extractor
This'll have to get overhauled once we support multi-goal queries, but for now
it'll do the job.
| author |
Steve Losh <steve@stevelosh.com> |
| date |
Fri, 15 Apr 2016 22:42:03 +0000 |
| parents |
9376531b5089 |
| children |
2f0b5c92febe |
(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))))))