What vim pattern matches a number which ends with dot?

Question

In PDP11/40 assembling language a number ends with dot is interpreted as a decimal number. I use the following pattern but fail to match that notation, for example, 8.:

syn match asmpdp11DecNumber /\<[0-9]\+\.\>/

When I replace \. with D the pattern can match 8D without any problem. Could anyone tell me what is wrong with my "end-with-dot" pattern? Thanks.

Answer 1

Your regular expression syntax is fine (well, you can use \d instead of [0-9]), but your 'iskeyword' value does not include the period ., so you cannot match the end-of-word (\>) after it.

It looks like you're writing a syntax for a custom filetype. One option is to

:setlocal filetype+=.

in a corresponding ~/.vim/ftplugin/asmpdp11.vim filetype plugin. Do this when the period character is considered a keyword character in your syntax.

Otherwise, drop the \> to make the regular expression match. If you want to ensure that there's no non-whitespace character after the period, you can assert that condition after the match, e.g. like this:

:syn match asmpdp11DecNumber /\<\d\+\.\S\@!/