In Vim, how can I automatically determine whether to use spaces or tabs for indentation

indentationvimwhitespace

Sometimes I edit others source code where the prevailing style is to use tabs. In this case, I want to keep the existing convention of using literal tabs.

For files I create myself, and files that use spaces as the prevailing indent style, I wish to use that instead.

How can I do this in vim?

Best Answer

You can use something like this in your ~/.vimrc to adjust to use spaces/tabs as appropriate:

" By default, use spaced tabs.
set expandtab

" Display tabs as 4 spaces wide. When expandtab is set, use 4 spaces.
set shiftwidth=4
set tabstop=4

function TabsOrSpaces()
    " Determines whether to use spaces or tabs on the current buffer.
    if getfsize(bufname("%")) > 256000
        " File is very large, just use the default.
        return
    endif

    let numTabs=len(filter(getbufline(bufname("%"), 1, 250), 'v:val =~ "^\\t"'))
    let numSpaces=len(filter(getbufline(bufname("%"), 1, 250), 'v:val =~ "^ "'))

    if numTabs > numSpaces
        setlocal noexpandtab
    endif
endfunction

" Call the function after opening a buffer
autocmd BufReadPost * call TabsOrSpaces()

Related Solutions

Python – How to make Kate indent with spaces on Python files but use tabs for text files and other files

There are multiple ways to achieve what you want. In order, Kate is doing the following:

Kate reads the settings that are configured globally in the config dialog in the Indentation tab.
Kate reads optional session data, i.e. if you use sessions and manually chose settings in a file, these settings should be restored again when opening the file.
Kate reads the "Filetype" configuration: The filetype, also called mode, can be configured in Settings > Configure Kate > Open/Save > Modes & Filetypes tab. Choose your filetype, e.g. Scripts/Python and then add a modeline like this: kate: indent-pasted-text false; indent-width 4;
Kate searches for document variables in .kateconfig files recursively upwards. If found, it will apply these settings
Kate reads document variables in the document itself. So in a Python file, you can simply add a comment in the first or last 10 lines of the file and write e.g.:# kate: indent-pasted-text false; indent-width 4;

All this is also described in the Kate Handbook.

Text Processing Awk Indentation – How to Use Awk to Indent a Source File Based on Simple Rules

With awk:

awk '
  /^end/ { sub("  ", "", indent) } # Or { indent = substr(indent, 3) }
  { print indent, $0 }
  /^describe/ { indent = indent"  " }
' <file

Best Answer

Related Solutions

Python – How to make Kate indent with spaces on Python files but use tabs for text files and other files

Text Processing Awk Indentation – How to Use Awk to Indent a Source File Based on Simple Rules

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