Optimize Syslog date rule using keywords in place of combinations

The previous rule used combinations of Day and Month three letter terms,
and was taking up about 30% of the syntax processing time.
The new methods using keywords has the side effect of highlighting the
three letter identifies in the whole file (they should be reasonably
rare outside of dates, however) but is much faster

README.md

@@ -46,14 +46,14 @@ You can add additional log level keywords using the standard VIM syntax function
 
 ```viml
 " Add custom level identifiers
-syn keyword logLevelError MY_CUSTOM_ERROR_KEYWORD
+au rc Syntax log syn keyword logLevelError MY_CUSTOM_ERROR_KEYWORD
 ```
 
 Likewise you can disable highlighting for elements you don't need:
 
 ```viml
 " Remove highlighting for URLs
-syn clear logUrl
+au rc Syntax log syn clear logUrl
 ```
 
 

ftdetect/log.vim

@@ -1,4 +1,5 @@
 
 au BufNewFile,BufRead *.log set filetype=log
 au BufNewFile,BufRead *_log set filetype=log
-
+au BufNewFile,BufRead *.LOG set filetype=log
+au BufNewFile,BufRead *_LOG set filetype=log

syntax/log.vim

@@ -1,7 +1,7 @@
 " Vim syntax file
 " Language:         Generic log file
 " Maintainer:       MTDL9 <https://github.com/MTDL9>
-" Latest Revision:  2019-04-16
+" Latest Revision:  2020-08-23
 
 if exists('b:current_syntax')
   finish
@@ -13,7 +13,7 @@ set cpoptions&vim
 
 " Operators
 "---------------------------------------------------------------------------
-syn match logOperator display '[;,\?\:\.\<=\>\~\/\@\&\!$\%\&\+\-\|\^(){}\*#]'
+syn match logOperator display '[;,\?\:\.\<=\>\~\/\@\!$\%&\+\-\|\^(){}\*#]'
 syn match logBrackets display '[\[\]]'
 syn match logEmptyLines display '-\{3,}'
 syn match logEmptyLines display '\*\{3,}'
@@ -43,15 +43,16 @@ syn region logString      start=/'\(s \|t \| \w\)\@!/ end=/'/ end=/$/ end=/s / s
 syn match logDate '\d\{2,4}[-\/]\(\d\{2}\|Jan\|Feb\|Mar\|Apr\|May\|Jun\|Jul\|Aug\|Sep\|Oct\|Nov\|Dec\)[-\/]\d\{2,4}T\?'
 " Matches 8 digit numbers at start of line starting with 20
 syn match logDate '^20\d\{6}'
-" Matches Fri Jan 09 or Feb 11 or Apr  3
-syn match logDate '\(\(Mon\|Tue\|Wed\|Thu\|Fri\|Sat\|Sun\) \)\?\(Jan\|Feb\|Mar\|Apr\|May\|Jun\|Jul\|Aug\|Sep\|Oct\|Nov\|Dec\) [0-9 ]\d'
+" Matches Fri Jan 09 or Feb 11 or Apr  3 or Sun 3
+syn keyword logDate Mon Tue Wed Thu Fri Sat Sun Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec nextgroup=logDateDay
+syn match logDateDay '\s\{1,2}\d\{1,2}' contained
 
 " Matches 12:09:38 or 00:03:38.129Z or 01:32:12.102938 +0700
 syn match logTime '\d\{2}:\d\{2}:\d\{2}\(\.\d\{2,6}\)\?\(\s\?[-+]\d\{2,4}\|Z\)\?\>' nextgroup=logTimeZone,logSysColumns skipwhite
 
 " Follows logTime, matches UTC or PDT 2019 or 2019 EDT
-syn match logTimeZone '\(UTC\|PDT\|EDT\|GMT\|EST\|KST\)\( \d\{4}\)\?' contained
-syn match logTimeZone '\d\{4} \(UTC\|PDT\|EDT\|GMT\|EST\|KST\)' contained
+syn match logTimeZone '[A-Z]\{2,5}\>\( \d\{4}\)\?' contained
+syn match logTimeZone '\d\{4} [A-Z]\{2,5}\>' contained
 
 
 " Entities
@@ -64,7 +65,7 @@ syn match logIPV4       '\<\d\{1,3}\(\.\d\{1,3}\)\{3}\>'
 syn match logIPV6       '\<\x\{1,4}\(:\x\{1,4}\)\{7}\>'
 syn match logMacAddress '\<\x\{2}\(:\x\{2}\)\{5}'
 syn match logFilePath   '\<\w:\\[^\n|,; ()'"\]{}]\+'
-syn match logFilePath   '\/\w[^\n|,; ()'"\]{}]\+'
+syn match logFilePath   '[^a-zA-Z0-9"']\@<=\/\w[^\n|,; ()'"\]{}]\+'
 
 
 " Syslog Columns
@@ -85,7 +86,7 @@ syn match logXmlAttribute    contained "\(\n\|\s\)\(\(\w\|-\)\+:\)\?\(\w\|-\)\+\
 syn match logXmlNamespace    contained "\(\w\|-\)\+:" contains=logOperator
 syn region logXmlComment     start=/<!--/ end=/-->/
 syn match logXmlCData        /<!\[CDATA\[.*\]\]>/
-syn match logXmlEntity       /\&\w\+;/
+syn match logXmlEntity       /&#\?\w\+;/
 
 
 " Levels
@@ -112,6 +113,7 @@ hi def link logNull Constant
 hi def link logString String
 
 hi def link logDate Identifier
+hi def link logDateDay Identifier
 hi def link logTime Function
 hi def link logTimeZone Identifier