The first of these is easily accomplished using【Ctrl+w】from within
isearch but that takes an extra key chord. With Petton's code you just invoke his
isearch-thing function and it searches for the symbol at point unless there is an active region.
If you are a heavy user of
isearch and find yourself typing 【Ctrl+s】 and then 【Ctrl+w】 a lot, this may be win for you.