compatibility fix for look-behind limit

Author: kljohann

syntax/ledger.vim

@@ -13,6 +13,7 @@ endif
 
 " Force old regex engine (:help two-engines)
 let s:oe = v:version < 704 ? '' : '\%#=1'
+let s:lb1 = v:version < 704 ? '\@<=' : '\@1<='
 
 " for debugging
 syntax clear
@@ -30,9 +31,9 @@ syn match ledgerPosting /^\s\+[^[:blank:];][^;]*\ze\%($\|;\)/
 " every space in an account name shall be surrounded by two non-spaces
 " every account name ends with a tab, two spaces or the end of the line
 exe 'syn match ledgerAccount '.
-  \ '/'.s:oe.'^\s\+\zs\%(\S\@1<= \S\|\S\)\+\ze\%(  \|\t\|\s*$\)/ contained'
+  \ '/'.s:oe.'^\s\+\zs\%(\S'.s:lb1.' \S\|\S\)\+\ze\%(  \|\t\|\s*$\)/ contained'
 exe 'syn match ledgerAmount '.
-  \ '/'.s:oe.'\S\@1<=\%(  \|\t\)\s*\zs\%([^;[:space:]]\|\s\+[^;[:space:]]\)\+/ contained'
+  \ '/'.s:oe.'\S'.s:lb1.'\%(  \|\t\)\s*\zs\%([^;[:space:]]\|\s\+[^;[:space:]]\)\+/ contained'
 
 syn region ledgerPreDeclaration start=/^\(account\|payee\|commodity\|tag\)/ skip=/^\s/ end=/^/
     \ keepend transparent