Tabs for indentation, spaces for alignment

Question

I am trying to make vim auto indent with tabs, and align with whitespaces, but actually, vim indent with tabs and fill the alignment with tabs + white spaces.

Vim does it :

(each block is a tab)

{
>--long a = 1,
>-->--..b = 2,
>-->--..c = 3;
}

May do it :

{
>--long a = 1,
>--.....b = 2,
>--.....c = 3;
}

So, I think there is a lot of questions about the subject of tabs and spaces, but none of them provide some Just Works solution:

• https://stackoverflow.com/questions/8493705/vim-use-tabs-for-indentation-spaces-for-alignment-with-c-source-files
• https://stackoverflow.com/questions/29208431/vim-indent-with-tabs-align-with-spaces
• https://stackoverflow.com/questions/6504507/vim-indenting-and-alignment-combining-spaces-and-tabs

Actually I am using:

set ai
set cindent
set cinoptions=(0,:0,u0,U0,g0)

I tried the Smart Tab plugin, which seems to work well, but when I try gg=G I get some weird errors :

Error detected while processing function CtabRedoIndent..<SNR>12_CheckAlign:
line   11:
E108: No such variable: "b:ctab_lastalign"
Press ENTER or type command to continue
Error detected while processing function CtabRedoIndent:
line   10:
E170: Missing :endwhile

This discussion seems to be prety old, so now, 2015, there is a official solution to deal with it ?

Answer 1

Doing this truly automatically is difficult. Vim doesn't know what is "indentation" and what is "alignment"; and some people may disagree on what exactly constitutes indentation and alignment.

That being said, the Smart Tabs plugin is designed to do what you want; I found that it works reasonably well for C files, but has a number of caveats; it breaks Python files, for example, and does some unexpected (for me, anyway) things for C files at times.
Looking at the source, I can't really figure out how it works in 5 minutes, and combined with the fact that it breaks some stuff, should tell you to proceed carefully...

Answer 2

The Smart Tabs plug-in that you mentioned is about as good as it gets. I initially ran into the same error that you did and gave up but eventually spent a few minutes to fix it. Try applying the following patch:

--- ctab.vim.orig   2016-08-11 17:05:20.767275274 +0800
+++ ctab.vim    2016-08-11 17:15:20.039286525 +0800
@@ -221,7 +221,7 @@
       if a:line == line('.')
         let b:ctab_lastalign=a:line
       else
-        unlet b:ctab_lastalign
+        unlet! b:ctab_lastalign
       endif
       set ts=50
       set sw=50

I later found that someone has suggested a similar fix in the Smart Tabs wiki section. Alas, there hasn't been a new release.

Answer 3

Indentation in vim is performed simply using the following script

Script to perform Indentation of a single file

#!/bin/bash 
#Author: Ankit shah
#Enter file name to indent as argument
file=$1
vim $file -c "normal gg=G" -c "wq"
#Use expand command to turn tabs into spaces. Code uniform across different vim environment
expand -t 4 $file $file