VIM: simple steps to create syntax highlight file - for logfiles...

Question

H have some (log4j generated) logfiles to go through; I know their format pretty well (I mean I have already got off-the-peg regexes etc I can use).

I want to automatically highlight them in VIM when I load them up (*.log).

A logfile entry looks something like this:

YYYY-MM-DD HH:MM:ss,SSS [...] #LOG-LEVEL# [...] Message

Where #LOG-LEVEL# is one of the standard 'ERROR', 'INFO', 'DEBUG', 'FATAL'....and the 'YYYY-MM...' represents the date/time to millisecond resolution.

To get me started , what are the steps needed to get the date-string highlighted in (say) yellow-background with blue text - and also when the text reads ' ERROR ' this should have a red-background with white text.

I have tried going through some tutorials on this, but can't find one which is simple enough to understand, so I'm after some real basic steps here !

Cheers

EDIT: Here's the summary of what I did, based on the instructions below:

1. Created the syntax file 'log.vim' in .vim\syntax (see below for example content).

2. Created a file in .vim\ftdetect\log.vim with the following content:

   au BufRead,BufNewFile *.log set filetype=log

3. Made sure the following are in my startup settings:

   syntax on filetype on

Answer 1

You can start from

syn match group1 /^\d\+-\d\+-\d\+/ nextgroup=group2 skipwhite
syn match group2 /....../ nextgroup=group3 contained skipwhite
syn match group3 /....../ nextgroup=group4 contained skipwhite

hi link group1 Comment
hi link group2 Conditional
hi link group3 Identifier

and then just continue to experiment

Answer 2

To load automatically with *.log files you should make an ftplugin for this filetype.

For example, in my log.vim file in my .vim/ftplugin folder I have simple instructions for setting a keyboard shortcut when loading *.log files.

Note: ftplugins may not be the best way to do this... setting the syntax file as Al describes is probably better. I'll leave this answer here though for the alternative possibility.

Answer 3

There are three ways of defining syntax items (see :help :syn-define):

• Keywords: these are for items that are simple strings of keyword characters. This is the fastest matcher.
• Matches: these are regular expressions for matching.
• Regions: these are for long regions that are likely to contain other items.

There are various arguments that make things more complicated (to do with matches within regions etc), see :help :syn-arguments for a discussion of this.

There is a priority that comes into effect (see :help :syn-priority).

Colouring is controlled by the highlight command and is separate to the syntax commands.

A simple way to get started would be to use a match to detect the date and a keyword to detect error. Then use highlight to make the colours come to life:

" This creates a keyword ERROR and puts it in the highlight group called logError
:syn keyword logError ERROR
" This creates a match on the date and puts in the highlight group called logDate.  The
" nextgroup and skipwhite makes vim look for logTime after the match
:syn match logDate /^\d\{4}-\d\{2}-\d\{2}/ nextgroup=logTime skipwhite

" This creates a match on the time (but only if it follows the date)
:syn match logTime /\d\{2}:\d\{2}:\d\{2},\d\{3}/

" Now make them appear:
" Link just links logError to the colouring for error
hi link logError Error
" Def means default colour - colourschemes can override
hi def logDate guibg=yellow guifg=blue
hi def logTime guibg=green guifg=white

Bung all of that in ~/.vim/syntax/log.vim and make sure the file type is set properly (see :help filetype.txt) - it should then load automatically.

Hopefully that should give you something to get going with. Have a (very gradual) read of the various sections of :help syntax.txt and :help usr_44.txt for further info.