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Egbert edited this page Mar 29, 2020 · 2 revisions

Debugging Vim Syntax File

Of all the things that I have tried to do in order to debug a brand-new syntax file for Vim editor, the following steps are my best and easiest to use and I hope they are to you as well.

this simple vim named.conf command will perform the following steps:

  • load the content of the named.conf file,
  • makes note of its filename AND filetype, then
  • reads in all ftdetect/*files for any of its matching filename/filetype
  • using ftdetect/<filenametype_match> that matched and flagged by filename/filetype
  • loads corresponding syntax/<filenametype_match>.vim of highlighters
  • reads syntaxes then displays highlighting

All that with just vim <your-test-file> command.

Preparing Your Home Settings

I use Dr. Chip hilinks.vim to support my debugging effort during this Vim syntax development.

Starting Out Debugging

Two terminal sessions are required for a successful debugging of any new or changed Vim syntax.

#) Editing/saving the changed Vim syntax (~/.vim/syntax/named.conf) file #) Re-viewing the target test-text (named.conf) file of its updated highlightings.

In the first terminal session, I did:

mkdir ~/.vim
mkdir ~/.vim/syntax
cp /usr/lib/vim/vim81/syntax/named.vim ~/.vim/syntax/
vim ~/.vim/syntax/named.vim

In a second terminal session, I cloned the target test-text file:

cp /etc/bind/named.conf /tmp/named.conf
vim /tmp/named.conf

In first terminal, I made a one-line change in ~/.vim/syntax/named.conf, saved it.

Then in second terminal, I edited my test-text named.conf file to see if I enhanced (or broke) something.

Sure enough, I broke it ... rather badly.

Go back to the beginning and do it over with a new syntax setting.

Documentation, Ugh.

In the very beginning, I was blindly making multiple syntax changes to my very own copy of an existing stock Vim syntax file.
It wasn't intuitive (not at all) and its results were "unpleasant."

Back to reading all relevant (and not-so-relevant) Vim documents, they are (but not limited to):

Those two were really all I need but still woefully inadequate for rapid startup of a robust debugging session for its syntax file.

The more changes I made to my copy of the stock Vim syntax file, the more I realized that I've got something brand new. None of the existing stock syntax exist anymore. It's morphed enough to be on its own but with an MIT License. I've been incorporating over 143 pseudo-BNF syntaxes, as a result I've re-christened this file as bind-named.vim in order not to conflict with the stock Vim syntax (syntax/named.vim) file.

Reloading New Changes

As one makes a change to its Vim syntax file (now called syntax/bind-named.vim) in 1st terminal session, you need to refresh the viewing (2nd) terminal session with your new syntaxes.

One method is to perform exiting the current Vim edit session on the target file being highlighted (named.conf) and then restarting the same Vim editor session, has become rather tedious as:

In the "editing" (1st) terminal session, edit the syntax (~/.vim/syntax/bind-named.conf) file and just simply save it:

(insert Vim editing keystrokes updating syntax)

and just save it (no need to quit the edit session):

:w

In the "viewing" (2nd) terminal session, exiting the vim editor:

:q

then re-entering same edit session:

vim named.conf

That's your basic development cycle of creating/changing the Vim syntax file.

Note that there is no debugging or troubleshooting steps there. It's a blind-man approach of hit-or-miss affair.

Programming Function Keys

Do this blind-man development cycle about 10,000 times (OK, so I'm exaggerating here but the point stands), and you'll desperately want for a single keystroke do all the work of 8 (tedious) keystrokes plus whatever the length of your test text file) after doing each and every single tweaking of your syntax file.

So let's go program some Vim function keys:

  • Detail highlight used on current cursor
  • Reload new syntax changes

Detail Highlight Function Key

I programmed the F10 function key to do the following:

  • F10 - Show which highlighter statement is being used at the current cursor

Stick this into your vimrc file (you remember where it is?):

" Show syntax highlighting macro at the cursor
map <F10> :echo "hi<" . synIDattr(synID(line("."),col("."),1),"name") . '> trans<'
\ . synIDattr(synID(line("."),col("."),0),"name") . "> lo<"
\ . synIDattr(synIDtrans(synID(line("."),col("."),1)),"name") . ">"<CR>

Now in your "viewing" (2nd) terminal session, the F10 key will show you which highlight syntax got used exactly where your cursor is currently at in your named.conf file.

Curious about a highlight that looks strange? Move the cursor to where that strange highlighting occurs at:

Initial Vim session

then press F10, and the status bar (at the bottom of 2nd terminal screen) comes alive with information showing:

hi<> trans<> lo<>

This means none of the entire system's syntax file found a syntax match to where the cursor is at.

Let's move the cursor around a bit more, until the cursor is over the word acl, a well-known Bind9 keyword:

After

then press F10 again:

hi<namedStmtKeyword> trans<namedStmtKeyword> lo<Statement>

This means namedStmtKeyword syntax was matched, transitioned from namedStmtKeyword, and got highlighted with a color of Statement.

Show Me The Colors!

I wanted to know what color was available in which I can use in my syntax; to get the colors actually used for the test-text file, execute in your "viewing" (2nd) Vim terminal for this example:

:syntax

Now you are seeing all the colors used for each statement (or lack thereof if you have forgotten). And its output is fed via Unix pipe through the less utility.
Use spacebar/PgUp/PgDn/Up/Down to scroll through the entire pre-processed syntax file during this :syntax viewing. Press q to quit.

Vim :syntax command is that first debugging tool showing you all the highlight syntaxes and its coloring. Very useful for one of final validations.

Reload Function Key

For the second function (F12) key, I found that Vim reload (:source $MYVIMRC) command. It's a nice command that does the equivalence (but, as I've discovered, NOT EXACTLY THE SAME) thing of reloading your newly changed Vim syntax file during a typical development cycle as described in the first section of this page.

NOTE: There may be some commands like :set ft=sh in your ~/.vimrc that WILL actually break the ability to cleanly reload your syntax-file-under-test.vim file: so, comment those out. I had to do the basic divide-and-conquer of putting:

finish

throughout my .vimrc file until the breakage stop breaking then commented out the offending lines (such as set ft=sh or syntax off).

The reload command basically rereads the vimrc files (there's more than one) which in turn reloads all applicable syntax/* files as determined by its filetype (.vim/ftdetect/bind-named.vim).

You can see a total list of vimrc files that VIM checked and read before displaying the content of its file being edited. I'll show you how to do this recreation of that list:

script /tmp/vim.strace
vim named.conf

And then blindly type in :q to quit the edit session and exit Vim editor. You can then scan for files that Vim opened by doing:

grep open /tmp/vim.strace | grep -v "No such file" | grep vim

That output list is:

openat(AT_FDCWD, "/usr/share/vim/vimrc", O_RDONLY) = 4
openat(AT_FDCWD, "/usr/share/vim/vim81/debian.vim", O_RDONLY) = 5
openat(AT_FDCWD, "/home/john/.vimrc", O_RDONLY) = 4
openat(AT_FDCWD, "/home/john/.vimrc.local", O_RDONLY|O_NONBLOCK) = 5
openat(AT_FDCWD, "/home/john/.vimrc.local", O_RDONLY) = 5
openat(AT_FDCWD, "/usr/share/vim/vim81/syntax/syntax.vim", O_RDONLY) = 6
openat(AT_FDCWD, "/usr/share/vim/vim81/syntax/synload.vim", O_RDONLY) = 7
openat(AT_FDCWD, "/home/john/.vim/syntax/syncolor.vim", O_RDONLY) = 8
openat(AT_FDCWD, "/usr/share/vim/vim81/syntax/syncolor.vim", O_RDONLY) = 8
openat(AT_FDCWD, "/usr/share/vim/vim81/rgb.txt", O_RDONLY) = 9
openat(AT_FDCWD, "/usr/share/vim/vim81/filetype.vim", O_RDONLY) = 7
openat(AT_FDCWD, "/home/john/.vim/ftdetect/", O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 8
openat(AT_FDCWD, "/home/john/.vim/ftdetect/bind-named.vim", O_RDONLY) = 8
openat(AT_FDCWD, "/home/john/.vim/ftdetect/bindzone.vim", O_RDONLY) = 8
openat(AT_FDCWD, "/home/john/.vim/ftdetect/bro.vim", O_RDONLY) = 8
openat(AT_FDCWD, "/home/john/.vim/ftdetect/nftables.vim", O_RDONLY) = 8
openat(AT_FDCWD, "/home/john/.vim/ftdetect/tatsu.vim", O_RDONLY) = 8
openat(AT_FDCWD, "/home/john/.vim/colors/elflord.vim", O_RDONLY) = 6
openat(AT_FDCWD, "/home/john/.vim/syntax/syncolor.vim", O_RDONLY) = 7
openat(AT_FDCWD, "/usr/share/vim/vim81/syntax/syncolor.vim", O_RDONLY) = 7
openat(AT_FDCWD, "/home/john/.vim/syntax/syncolor.vim", O_RDONLY) = 7
openat(AT_FDCWD, "/usr/share/vim/vim81/syntax/syncolor.vim", O_RDONLY) = 7
openat(AT_FDCWD, "/home/john/.vim/syntax/syncolor.vim", O_RDONLY) = 7
openat(AT_FDCWD, "/usr/share/vim/vim81/syntax/syncolor.vim", O_RDONLY) = 7
openat(AT_FDCWD, "/usr/share/vim/vim81/filetype.vim", O_RDONLY) = 5
openat(AT_FDCWD, "/usr/share/vim/vim81/filetype.vim", O_RDONLY) = 5
openat(AT_FDCWD, "/usr/share/vim/vim81/ftplugin.vim", O_RDONLY) = 5
openat(AT_FDCWD, "/usr/share/vim/vim81/syntax/syntax.vim", O_RDONLY) = 5
openat(AT_FDCWD, "/usr/share/vim/vim81/syntax/nosyntax.vim", O_RDONLY) = 6
openat(AT_FDCWD, "/usr/share/vim/vim81/syntax/synload.vim", O_RDONLY) = 6
openat(AT_FDCWD, "/home/john/.vim/colors/elflord.vim", O_RDONLY) = 7
openat(AT_FDCWD, "/home/john/.vim/syntax/syncolor.vim", O_RDONLY) = 8
openat(AT_FDCWD, "/usr/share/vim/vim81/syntax/syncolor.vim", O_RDONLY) = 8
openat(AT_FDCWD, "/home/john/.vim/syntax/syncolor.vim", O_RDONLY) = 8
openat(AT_FDCWD, "/usr/share/vim/vim81/syntax/syncolor.vim", O_RDONLY) = 8
openat(AT_FDCWD, "/home/john/.vim/colors/elflord.vim", O_RDONLY) = 5
openat(AT_FDCWD, "/home/john/.vim/syntax/syncolor.vim", O_RDONLY) = 6
openat(AT_FDCWD, "/usr/share/vim/vim81/syntax/syncolor.vim", O_RDONLY) = 6
openat(AT_FDCWD, "/home/john/.vim/syntax/syncolor.vim", O_RDONLY) = 6
openat(AT_FDCWD, "/usr/share/vim/vim81/syntax/syncolor.vim", O_RDONLY) = 6
openat(AT_FDCWD, "/usr/share/vim/vim81/pack/", O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4
openat(AT_FDCWD, "/home/john/.vim/plugin/", O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4
openat(AT_FDCWD, "/home/john/.vim/plugin/", O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4
openat(AT_FDCWD, "/home/john/.vim/plugin/hilinks.vim", O_RDONLY) = 4
openat(AT_FDCWD, "/var/lib/vim/addons/plugin/", O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4
openat(AT_FDCWD, "/var/lib/vim/addons/plugin/", O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4
openat(AT_FDCWD, "/var/lib/vim/addons/plugin/syntastic/", O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 5
openat(AT_FDCWD, "/var/lib/vim/addons/plugin/syntastic/", O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 5
openat(AT_FDCWD, "/var/lib/vim/addons/plugin/syntastic/autoloclist.vim", O_RDONLY) = 4
openat(AT_FDCWD, "/var/lib/vim/addons/plugin/syntastic/balloons.vim", O_RDONLY) = 4
openat(AT_FDCWD, "/var/lib/vim/addons/plugin/syntastic/checker.vim", O_RDONLY) = 4
openat(AT_FDCWD, "/var/lib/vim/addons/plugin/syntastic/cursor.vim", O_RDONLY) = 4
openat(AT_FDCWD, "/var/lib/vim/addons/plugin/syntastic/highlighting.vim", O_RDONLY) = 4
openat(AT_FDCWD, "/var/lib/vim/addons/plugin/syntastic/loclist.vim", O_RDONLY) = 4
openat(AT_FDCWD, "/var/lib/vim/addons/plugin/syntastic/modemap.vim", O_RDONLY) = 4
openat(AT_FDCWD, "/var/lib/vim/addons/plugin/syntastic/notifiers.vim", O_RDONLY) = 4
openat(AT_FDCWD, "/var/lib/vim/addons/plugin/syntastic/registry.vim", O_RDONLY) = 4
openat(AT_FDCWD, "/var/lib/vim/addons/plugin/syntastic/signs.vim", O_RDONLY) = 4
openat(AT_FDCWD, "/var/lib/vim/addons/plugin/syntastic.vim", O_RDONLY) = 4
openat(AT_FDCWD, "/var/lib/vim/addons/autoload/syntastic/util.vim", O_RDONLY) = 5
openat(AT_FDCWD, "/var/lib/vim/addons/plugin/syntastic/", O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 5
openat(AT_FDCWD, "/var/lib/vim/addons/plugin/syntastic/autoloclist.vim", O_RDONLY) = 5
openat(AT_FDCWD, "/var/lib/vim/addons/plugin/syntastic/balloons.vim", O_RDONLY) = 5
openat(AT_FDCWD, "/var/lib/vim/addons/plugin/syntastic/checker.vim", O_RDONLY) = 5
openat(AT_FDCWD, "/var/lib/vim/addons/plugin/syntastic/cursor.vim", O_RDONLY) = 5
openat(AT_FDCWD, "/var/lib/vim/addons/plugin/syntastic/highlighting.vim", O_RDONLY) = 5
openat(AT_FDCWD, "/var/lib/vim/addons/plugin/syntastic/loclist.vim", O_RDONLY) = 5
openat(AT_FDCWD, "/var/lib/vim/addons/plugin/syntastic/modemap.vim", O_RDONLY) = 5
openat(AT_FDCWD, "/var/lib/vim/addons/plugin/syntastic/notifiers.vim", O_RDONLY) = 5
openat(AT_FDCWD, "/var/lib/vim/addons/plugin/syntastic/registry.vim", O_RDONLY) = 5
openat(AT_FDCWD, "/var/lib/vim/addons/plugin/syntastic/signs.vim", O_RDONLY) = 5
openat(AT_FDCWD, "/usr/share/vim/vim81/plugin/", O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4
openat(AT_FDCWD, "/usr/share/vim/vim81/plugin/", O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4
openat(AT_FDCWD, "/usr/share/vim/vim81/plugin/getscriptPlugin.vim", O_RDONLY) = 4
openat(AT_FDCWD, "/usr/share/vim/vim81/plugin/gzip.vim", O_RDONLY) = 4
openat(AT_FDCWD, "/usr/share/vim/vim81/plugin/logiPat.vim", O_RDONLY) = 4
openat(AT_FDCWD, "/usr/share/vim/vim81/plugin/manpager.vim", O_RDONLY) = 4
openat(AT_FDCWD, "/usr/share/vim/vim81/plugin/matchparen.vim", O_RDONLY) = 4
openat(AT_FDCWD, "/usr/share/vim/vim81/plugin/netrwPlugin.vim", O_RDONLY) = 4
openat(AT_FDCWD, "/usr/share/vim/vim81/plugin/rrhelper.vim", O_RDONLY) = 4
openat(AT_FDCWD, "/usr/share/vim/vim81/plugin/spellfile.vim", O_RDONLY) = 4
openat(AT_FDCWD, "/usr/share/vim/vim81/plugin/tarPlugin.vim", O_RDONLY) = 4
openat(AT_FDCWD, "/usr/share/vim/vim81/plugin/tohtml.vim", O_RDONLY) = 4
openat(AT_FDCWD, "/usr/share/vim/vim81/plugin/vimballPlugin.vim", O_RDONLY) = 4
openat(AT_FDCWD, "/usr/share/vim/vim81/plugin/zipPlugin.vim", O_RDONLY) = 4
openat(AT_FDCWD, "/usr/share/vim/vim81/pack/", O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4
openat(AT_FDCWD, "/home/john/.viminfo", O_RDONLY) = 5
openat(AT_FDCWD, "/home/john/.viminfo", O_RDONLY) = 6
openat(AT_FDCWD, "/home/john/.vim/ftplugin/", O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 6
openat(AT_FDCWD, "/usr/share/vim/vim81/ftplugin/", O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 6
openat(AT_FDCWD, "/usr/share/vim/vim81/syntax/named.vim", O_RDONLY) = 6
openat(AT_FDCWD, "/var/lib/vim/addons/autoload/syntastic/log.vim", O_RDONLY) = 6
openat(AT_FDCWD, "/home/john/.viminfo", O_RDONLY) = 4
openat(AT_FDCWD, "/home/john/.viminfo.tmp", O_WRONLY|O_CREAT|O_EXCL|O_NOFOLLOW, 0600) = 6

So you can see that there is many syntax files checked before decided on syntax/named.vim due to named.conf filename/filetype detection as determined by ftdetect/named.conf.

To perform single-key reloading of your syntax-under-unit-test.vim file, put this near at the end of your ~/.vimrc of the file.

" Toggle reload of syntax files
" Didn't have desired effect on reloading syntax files; noremap <F12> <Esc>:source $MYVIMRC<CR>
"
noremap <F12> <Esc>:source $MYVIMRC<CR>
inoremap <F12> <C-o>:source $MYVIMRC<CR>

Now you have a reload function key at your very next Vim edit session.
Any changes you make to your ~/.vim/syntax/<test.vim> will immediately show the changes made by your recent changes to highlight syntax(es).

I saved myself from doing 18 keystrokes and going back and forth between two different terminal sessions by using this new F10 keystroke.

Now its 1st terminal, Vim :w command. And 2nd terminal, F12 key to reload new syntax file. Back and forth.

Continuous Status

Then as more serious debugging work requires (as I was about on my 5th of 134 pseudo-BNF syntaxes), this hitting F10 on each cursor position was starting to drive me mad until I get a clearer picture.

Searching for a better solution, I found this HiLinkTrace (hilinks) Vim bundle from Charles Campbell (aka Dr. Chip). It's an older version 4 but it works on my latest Vim v8.1!

Update: There is a later version v4m at Dr. Chip that is detailed on his website.

But I got mine git clone from Kergoth's Github.

Files are in "VimBall" format and often denoted using .vba filetype.

If you go the Dr. Chip route, execute:

mkdir ~/.vim/bundle
cd ~/.vim/bundle/
wget http://www.drchip.org/astronaut/vim/vbafiles/hilinks.vba.gz
gunzip hilinks.vba.gz

If you got it from Github (or Dr. Chip), then also execute:

mkdir ~/.vim/bundle
git clone https://github.com/kergoth/vim-hilinks
cd vim-hilinks
vim hilinks.vba

And from either methods above, execute:

" execute the current file
:source %

It now installed! And ready for your next new Vim edit session.

Activating Live HiLinks Status

After that strange Vimball installation (remember, my lab is offline so remote updating within Vim plugins is not an option for me), I'm now starting up a new "viewing" (2nd) terminal session.

I see my highlighted keywords and identifiers in bind-named.conf.

To see the live status of where ever I move my cursor to, the current status is displayed at the status bar below. Activate this by executing:

:HLTm

The status bar comes alive with:

SynStack:  namedStmtKeyword HltTrace: namedStmtKeyword->namedHLStatement->Statement fg<11> bg<>

My cursor was over the acl keyword when I saw the above status bar. The breakdown of the status bar is:

  • SynStack - Syntax stack content
  • HltTrace - Highlight tracing
  • fg - Foreground color used
  • bg - Background color used

For SynStack, the syntax stack content is namedStmtKeyword. This means that the nesting part of syntax calling other syntax (calling other syntax) is one level deep. First syntax encountered. Nothing fancy. Nice and simple.

For HltTrace, this is a function of which highlighting color got used. Each level (->) is an alias of another level. First one is the top-level highlight color name associated with the SynStack (coincidentally also named namedStmtKeyword). Each alias takes us closer to the actual color used. namedHLStatement is a generic syntax/bind-named.vim-specific alias. And Statement is a default Vim color.

For fg foreground color, it uses ANSI color 11.

And after some digging on the Internet, I show that Vim color code scheme to be:

The Vim colors are:
            0    black
            1    dark red
            2    dark green
            3    brown
            4    dark blue
            5    dark magenta
            6    dark cyan
            7    light grey
            8    dark grey
            9    red
            10   green
            11   yellow
            12   blue
            13   magenta
            14   cyan
            15   white

Bigger And Deeper

As I developed more nested syntaxes and used longer syntax function name, the one-line status bar got overrun and made a screen mess of things.

I fixed that by expanding the status bar into a 2-line status bar.

To activate a 2-line status at the bottom of your Vim terminal session and start showing your longer highlight debug information as you move your cursor around:

:set laststatus=2

That is all for now.

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