Why is this thing (isearch-search-fun) coded like this?

[Alan Mackenzie]

Hello, Emacs.

I'm absolutely stumped.

`isearch-search-fun', when called, returns a function "to use" for
searching.  To do this, it funcalls .....

.... `isearch-search-fun-default'.  This returns a constant lambda form.

CONSTANT LAMBDA FORMS ARE NOT EASY TO INSTRUMENT FOR EDEBUG!!!!

As an alternative, isearch-search-fun-default could simply return a
named function.  Even better, such a named function could simply be, and
be returned directly from `isearch-search-fun' without all the
superfluous funcalling.

Or am I missing something here?

All this "is a function which returns a function by funcalling a
function which returns a constant lambda form" has exhausted any desire
I had to debug my problem to a finish.

I'm tempted to rip out a lot of this stuff from Isearch to be able to
debug it.  Will I regret it if I do?

-- 
Alan Mackenzie (Nuremberg, Germany).