Convert `filter` from a function to a macro

Doesn't make a big difference, just for fun. I like the idea of a
compile-time version of this since it's essentially just renaming
`remove-if-not`.

Move it to a new file so we can include it before it's used in
`main.lisp`.

1 files changed, 0 insertions, 3 deletions

diff --git a/l/src/main.lisp b/l/src/main.lisp
index 6abe363..42c0ccd 100644
--- a/l/src/main.lisp
+++ b/l/src/main.lisp
@@ -91,6 +91,3 @@
                       "background_page")))
 
     (filter #'extensionp targets)))
-
-(defun filter (predicate list-form)
-  (remove-if-not predicate list-form))