Monday, 6 August 2018

Scripting my Vim Editor


As an inveterate vim user the first thing (or one of the first things) I'd do when starting a new project under Windows is installing vim to use it for searching, grapping and editing logfiles when I'm bugfixing. Or just a to use it as a general viewer for all sorts of files.

Typically I'd set up my toolbar buttons (for vim 7.4) like that:
"" Caution: Needs 18x18 bitmaps in "C:\Program Files (x86)\Vim\vim73\bitmaps" !!!
:amenu ToolBar.-SEP- :
:tmenu ToolBar.tabedit Open new tab (mrkkrj)
:amenu ToolBar.tabedit :tabedit<cr>

:tmenu ToolBar.darklight Switch color themes (mrkkrj)
:amenu ToolBar.darklight :colo zellner<cr>
:tmenu ToolBar.lightdark Switch color themes (mrkkrj)
:amenu ToolBar.lightdark :colo torte<cr>

:tmenu ToolBar.smallfont Smaller font (mrkkrj)
:amenu ToolBar.smallfont :set guifont=Lucida_Console:h9<cr>
:tmenu ToolBar.bigfont Bigger font (mrkkrj)
:amenu ToolBar.bigfont :set guifont=Lucida_Console:h10<c>
This gives me my standard button toolbar with buttons for switching fonts and and colors from big to small and from dark to light, plus a button for opening new tabs:


Somehow this was always enough, beacuse I just used my default dark scheme  plus one more dark and an alternative light one. As you know the colors depend on the monitir you are using and the room you are sitting in, so in my new project I wanted to toggle through several schemes and font sizes before I settle down with my favorite. Thus I introduced following functions:
:tmenu ToolBar.darklight Switch color themes (mrkkrj)
:amenu ToolBar.darklight :call ToggleLightScheme()<cr>
:tmenu ToolBar.lightdark Switch color themes (mrkkrj)
:amenu ToolBar.lightdark :call ToggleDarkScheme()<cr>

:tmenu ToolBar.smallfont Smaller font (mrkkrj)
:amenu ToolBar.smallfont :set guifont=Lucida_Console:h9<cr>
:tmenu ToolBar.bigfont Bigger font (mrkkrj)
:amenu ToolBar.bigfont :call ToggleBigFontSize()<c>
Next thing is to write the actual functions to toggle between dark and light color schemes. What I did was toggling between 2 light and 2 dark color schemes like that:
:function ToggleDarkScheme()
:  if exists('g:colors_name')
:    if g:colors_name == 'evening'
:      colo darkblue
:    else
:      colo evening
:  endif
:  else
:      colo evening
:  endif
:endfunction

:function ToggleLightScheme()
:  if exists('g:colors_name')
:    if g:colors_name == 'zellner'
:      colo delek
:    else
:      colo zellner
:  endif
:  else
:      colo delek
:  endif
:endfunction
Toggling of fonts had to be done a little different, because there's no global variable that vim would set when fonts are changing like the g:colors_name above. So I had to introduce my own: g:guifonts_name:
let g:guifonts_name = 'Lucida_Console:h10'

:function ToggleBigFontSize()
:    if g:guifonts_name == 'Lucida_Console:h10'
:      set guifont=Lucida_Console:h12
:      let g:guifonts_name = 'Lucida_Console:h12'
:    else
:      set guifont=Lucida_Console:h10
:      let g:guifonts_name = 'Lucida_Console:h10'
:  endif
:endfunction
Admittedly this is not a pretty and general solution: if I needed more colors or fonts I'd have to add more ugly if-else clauses. The ceneral soultion would be of course  to create a local array of color schemes and cycle through it like it is shown here*. But "form follows function..." and "use before reuse..." 😉 - and frankly, I didn't have time for that, vimscript's syntax** is pretty weird.

--
* "Switch Color Schemes" in Vim Tips Wiki: http://vim.wikia.com/wiki/Switch_color_schemes

** There some good intros you can use to deepen your knowledge of vim scripting:

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