Vim Syntax Highlighting: highlight `self` python keyword with regex

Question

I am trying to customize the syntax highlighting for python in vim. I want to highlight the keyword self but only when it is followed by a .. Here is the code I came up with:

syn match   pythonBoolean     "\(\Wself\)\%(\.\)"

Unfortunately, the . is also highlighted though I use a non capturing group \%(\.\).

Any idea?

I tried it, it does't change a thing. From my understanding, `\v` allows to avoid escaping special characters like parentheses, etc. — BiBi, Jul 05 '16 at 12:13
@aragaer you're right, but whether it is a keyword or not doesn't change the problem at hand. — BiBi, Jul 05 '16 at 12:42

Meninx - メネンックス · Accepted Answer · 2016-07-05T12:49:50.167

6

You need to use the lookaround:

:syn match pythonBoolean "\(\W\|^\)\zsself\ze\."

or

:syn match pythonBoolean "\(\W\|^\)\@<=self\(\.\)\@="

edited Jul 05 '16 at 12:49

answered Jul 05 '16 at 12:42

Meninx - メネンックス

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Worked like a charm! Thanks. – BiBi Jul 05 '16 at 12:48

score 2 · Answer 2 · answered Mar 29 '17 at 18:38

Building on @Meninx's answer, I added this to my .vimrc:

augroup PythonCustomization
  " highlight python self, when followed by a comma, a period or a parenth
   :autocmd FileType python syn match pythonStatement "\(\W\|^\)\@<=self\([\.,)]\)\@="
augroup END

Note 1: that in addition to what the op asked, it will also highlight when self is followed by a comma or a closing parenthesis.

Note 2: instead of using pythonBoolean, this highlights self using pythonStatement (personal preference). You can use other highlight-groups (run :syn with a python file open to see what's available)

score 1 · Answer 3 · edited May 23 '17 at 12:26

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How about using lookbehinds and lookaheads? A valid regex for an occurence of self preceded by any non-word character [^a-zA-Z0-9_] and followed by . in common regex syntax is: (?<=\W)(self)(?=\.)

For vim regex take a look at this answer, and, if you need more help, check this page out.

edited May 23 '17 at 12:26

Community

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answered Jul 05 '16 at 12:33

Nee

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score 1 · Answer 4 · answered Jul 06 '16 at 08:25

1

As an alternative to lookbehind and lookahead, which tend to slow down vim:

syn match pythonBoolean "\<self\ze\."

Or, in case you want to highlight all objects:

syn match pythonBoolean "\<\w\+\ze\."

answered Jul 06 '16 at 08:25

Vitor

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Vim Syntax Highlighting: highlight `self` python keyword with regex

4 Answers4