symbols verses words

[Perry Smith <pedzsan@gmail.com>]

I need some help understanding Emac's design.  I use a lot of "word" constructs where I *think* I should be using symbol.  For example, if I'm writing C code and I want to find foo but not foo_bar, I usually do \<foo\> but really it seems that I should be doing \_<foo\_> ... fine.  I can make that adjustment.  But when I do incremental search, I often hit ^w to pull in the next word but what I really want (often but not always) is to pull in the next symbol (into the search string).  So if I'm sitting at this_that, I'd ilke to hit ^W (perhaps) and pull in this_that instead of just this.

So, I started looking at isearch-yank-word-or-char and I was going to concoct isearch-yank-symbol-or-char and got stuck-- at least briefly.  Because not only is _ marked as symbol, -, +, /, *, etc are marked as symbol characters too.  So now, I'm confused...

If I have:  this  this_that  this-that

and search for \_<this\_> I hit the first and third this -- which is exactly what I want.  But how is it doing that since this_that and this-that are the same as far as looking at the syntax table entries?  They are both wwww_wwww.

I'd like to understand how the \_< and \_> constructs work so I can make my isearch-yank-symbol-or-char work in a consistent manner.

Thanks,
Perry