ENH: Add g:mwExclusionPredicates to be able to suppress mark highligh…

…ting in window(s)

Now that the mark highlighting update goes through the single mark#UpdateMark() function, we can add an evaluation of user-configured Predicates (as expressions or Funcrefs). If the current window should be skipped for highlighting (for the plugin, the marks are still "there" and can be added / removed, and jumped to, even though there're invisible), existing match highlighting is removed instead of updated.
By default, consider boolean "nomarks" flag variables for various scopes, as these (especially the buffer-local b:nomarks) can be easily set in filetype plugins.
To make this work with changing buffers, we have to run an additional unconditional mark update on BufWinEnter.

Resolves inkarkat#2.

README.md

@@ -415,6 +415,30 @@ override the default behavior of using 'ignorecase' by setting:
 
         let g:mwIgnoreCase = 0
 
+To exclude some tab pages, windows, or buffers / filetypes from showing mark
+highlightings (you can still "blindly" navigate to marks in there with the
+corresponding mappings), you can define a List of expressions or Funcrefs that
+are evaluated in every window; if one returns 1, the window will not show
+marks.
+
+    " Don't mark temp files, Python filetype, and scratch files as defined by
+    " a custom function.
+    let g:mwExclusionPredicates =
+    \   ['expand("%:p") =~# "/tmp"', '&filetype == "python", function('ExcludeScratchFiles')]
+
+By default, tab pages / windows / buffers that have t:nomarks / w:nomarks /
+b:nomarks with a true value are excluded. Therefore, to suppress mark
+highlighting in a buffer, you can simply
+
+    :let b:nomarks = 1
+
+If the predicate changes after a window has already been visible, you can
+update the mark highlighting by either:
+- switching tab pages back and forth
+- toggling marks on / off (via <Plug>MarkToggle)
+- :call mark#UpdateMark() (for current buffer)
+- :call mark#UpdateScope() (for all windows in the current tab page)
+
 You can use different mappings by mapping to the <Plug>Mark... mappings (use
 ":map <Plug>Mark" to list them all) before this plugin is sourced.
 
@@ -519,6 +543,9 @@ HISTORY
   pattern.
 - BUG: Regression: <Leader>n without {N} and not on an existing mark prints
   error "Do not pass empty pattern to disable all marks".
+- ENH: Allow to exclude certain tab pages, windows, or buffers / filetypes
+  from showing mark highlightings via g:mwExclusionPredicates or (with the
+  default predicate) t:nomarks / w:nomarks / b:nomarks flags.
   __You need to update to ingo-library ([vimscript #4433](http://www.vim.org/scripts/script.php?script_id=4433)) version 1.035!__
 
 ##### 3.0.0   18-Sep-2017

autoload/mark.vim

@@ -152,6 +152,10 @@ function! mark#NextUsedGroupIndex( isBackward, isWrapAround, startIndex, count )
 	return -1
 endfunction
 
+function! mark#DefaultExclusionPredicate()
+	return (exists('b:nomarks') && b:nomarks) || (exists('w:nomarks') && w:nomarks) || (exists('t:nomarks') && t:nomarks)
+endfunction
+
 " Set match / clear matches in the current window.
 function! s:MarkMatch( indices, expr )
 	if ! exists('w:mwMatch')
@@ -197,6 +201,16 @@ function! s:MarkMatch( indices, expr )
 endfunction
 " Initialize mark colors in a (new) window.
 function! mark#UpdateMark( ... )
+	for l:Predicate in g:mwExclusionPredicates
+		if ingo#actions#EvaluateOrFunc(l:Predicate)
+			" The window may have had marks applied previously. Clear any
+			" existing matches.
+			call s:MarkMatch(range(s:markNum), '')
+
+			return
+		endif
+	endfor
+
 	if a:0
 		call call('s:MarkMatch', a:000)
 	else
@@ -1117,6 +1131,7 @@ endfunction
 
 augroup Mark
 	autocmd!
+	autocmd BufWinEnter * call mark#UpdateMark()
 	autocmd WinEnter * if ! exists('w:mwMatch') | call mark#UpdateMark() | endif
 	autocmd TabEnter * call mark#UpdateScope()
 augroup END

doc/mark.txt

@@ -418,6 +418,28 @@ If you have set 'ignorecase', but want marks to be case-insensitive, you can
 override the default behavior of using 'ignorecase' by setting: >
 	let g:mwIgnoreCase = 0
 <
+						     *g:mwExclusionPredicates*
+To exclude some tab pages, windows, or buffers / filetypes from showing mark
+highlightings (you can still "blindly" navigate to marks in there with the
+corresponding mappings), you can define a List of expressions or Funcrefs that
+are evaluated in every window; if one returns 1, the window will not show
+marks. >
+    " Don't mark temp files, Python filetype, and scratch files as defined by
+    " a custom function.
+    let g:mwExclusionPredicates =
+    \	['expand("%:p") =~# "/tmp"', '&filetype == "python", function('ExcludeScratchFiles')]
+<					   *t:nomarks* *w:nomarks* *b:nomarks*
+By default, tab pages / windows / buffers that have t:nomarks / w:nomarks /
+b:nomarks with a true value are excluded. Therefore, to suppress mark
+highlighting in a buffer, you can simply >
+    :let b:nomarks = 1
+If the predicate changes after a window has already been visible, you can
+update the mark highlighting by either:
+- switching tab pages back and forth
+- toggling marks on / off (via <Plug>MarkToggle)
+- :call mark#UpdateMark() (for current buffer)
+- :call mark#UpdateScope() (for all windows in the current tab page)
+
 
 							       *mark-mappings*
 You can use different mappings by mapping to the <Plug>Mark... mappings (use
@@ -518,6 +540,9 @@ HISTORY								*mark-history*
   pattern.
 - BUG: Regression: <Leader>n without {N} and not on an existing mark prints
   error "Do not pass empty pattern to disable all marks".
+- ENH: Allow to exclude certain tab pages, windows, or buffers / filetypes
+  from showing mark highlightings via g:mwExclusionPredicates or (with the
+  default predicate) t:nomarks / w:nomarks / b:nomarks flags.
   *** You need to update to ingo-library (vimscript #4433) version 1.035! ***
 
 3.0.0	18-Sep-2017

plugin/mark.vim

@@ -66,6 +66,10 @@ if ! exists('g:mwDirectGroupJumpMappingNum')
 	let g:mwDirectGroupJumpMappingNum = 9
 endif
 
+if ! exists('g:mwExclusionPredicates')
+	let g:mwExclusionPredicates = [function('mark#DefaultExclusionPredicate')]
+endif
+
 
 "- default highlightings ------------------------------------------------------