Re: change-log-goto-source: recognising . within tag names

[martin rudalics <rudalics@gmx.at>]

 > change-log-goto-source is a great function for finding the definition of
 > a function mentioned in a changelog.  I'm looking for some help though
 > getting it to work recognising tags in the language R (a popular
 > statistics environment).  In R, function names are often include the
 > period character, e.g. t.test().  When using change-log-goto-source on
 > these kinds of tags, the correct tag is not found because . is of the
 > syntax class 'punctuation', and it looks to me like the tags must be made
 > of  elements of syntax class 'word'.

`word' or `symbol'.

 > How to fix this?  I tried changing the regexp, but this didn't work:
 >
 > (defconst change-log-tag-re
 >   "(\\(\\(?:\\sw\\|\\s_\\|\\.\\)+\\(?:[, \t]+\\(?:\\sw\\|\\s_\\|\\.\\)+\\)*\\))"
 >   "Regexp matching a tag name in change log entries.")

This won't be sufficient because `find-tag-default' (which is called by
`change-log-search-tag-name-1') also works on symbols only and
`change-log-mode' is derived from `text-mode' :-(

I'm afraid `change-log-search-tag-name' is too clever when trying to
find a suitable tag.  Usually, it seems sufficient to search for the
previous and next property change of the `change-log-list' text property
near `point' and return the corresponding string.  Maybe we should
provide a `change-log-search-tag-name-function' people could set to do
the job.  Or, simply set the `syntax-table' text property to `symbol'
for periods preceded _and_ followed by word/symbol characters.

martin