Add `:key` for `extrema`
author |
Steve Losh <steve@stevelosh.com> |
date |
Thu, 05 Dec 2019 19:41:57 -0500 |
parents |
a8b03be59283 |
children |
d8fe9c6ee9f4 |
(in-package :losh.mutation)
(eval-when (:compile-toplevel :load-toplevel :execute)
(defun build-zap (place expr env)
(multiple-value-bind (temps exprs stores store-expr access-expr)
(get-setf-expansion place env)
`(let* (,@(mapcar #'list temps exprs)
(,(car stores) (symbol-macrolet ((% ,access-expr))
,expr)))
,store-expr))))
(defmacro zapf (&rest place-expr-pairs &environment env)
"Update each `place` by evaluating `expr` with `%` bound to the current value.
`zapf` works like `setf`, but when evaluating the value expressions the symbol
`%` will be bound to the current value of the place.
Examples:
(zapf foo (1+ %)
(car bar) (if (> % 10) :a :b))
"
;; original idea/name from http://malisper.me/2015/09/29/zap/
`(progn
,@(loop :for (place expr . nil) :on place-expr-pairs :by #'cddr
:collect (build-zap place expr env))))
(define-modify-macro mulf (factor) *
"Multiply `place` by `factor` in-place.")
(defun %divf (value &optional divisor)
(if divisor
(/ value divisor)
(/ value)))
(define-modify-macro divf (&optional divisor) %divf
"Divide `place` by `divisor` in-place.
If `divisor` is not given, `place` will be set to `(/ 1 place)`.
")
(define-modify-macro modf (divisor) mod
"Modulo `place` by `divisor` in-place.")
(define-modify-macro remainderf (divisor) rem
"Remainder `place` by `divisor` in-place.")
(define-modify-macro clampf (from to) losh.math:clamp
"Clamp `place` between `from` and `to` in-place.")
(define-modify-macro negatef () -
"Negate the value of `place`.")
(define-modify-macro notf () not
"Set `place` to `(not place)` in-place.")
(defun %funcall (value function)
(funcall function value))
(define-modify-macro %callf (function) %funcall
"Set `place` to the result of calling `function` on its current value.")
(defmacro callf (&rest place-function-pairs)
"Set each `place` to the result of calling `function` on its current value.
Examples:
(let ((x 10) (y 20))
(callf x #'1-
y #'1+)
(list x y))
=>
(9 21)
"
`(progn
,@(loop :for (place function . nil) :on place-function-pairs :by #'cddr
:collect `(%callf ,place ,function))))