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Vim Flog Plugin

(Forked from Ruby Cyclomatic Complexity Plugin created by @skammer)

Indicates the Flog number in front of the action in your Ruby code to indicate the complexity.

Screen shot


  • ruby
  • flog rubygem
  • vim 7.3+, compiled with:
    • +ruby
    • +signs


First of all make sure you have a Vim installed with Ruby support. If you use MacVim than you can build your own version of Vim like this.

Here is an example of my configuration during the build:

./configure --with-features=huge --enable-rubyinterp --enable-pythoninterp --enable-perlinterp --enable-cscope

Install the Flog gem like this: gem install flog.

To install the plugin just run this command in your Terminal:

curl -o ~/.vim/plugin/flog.vim

When this is done add :silent exe "g:flog_enable" to your .vimrc file.


You can set the colors for the complexity indication with the following commands in your .vimrc:

  • Set the color of for low complexity:
    :let g:flog_low_color_hl = "term=standout ctermfg=118 ctermbg=235 guifg=#999999 guibg=#323232"

  • Set the color of for medium complexity:
    :let g:flog_medium_color_hl = "term=standout ctermfg=81 ctermbg=235 guifg=#66D9EF guibg=#323232"

  • Set the color of for high complexity:
    :let g:flog_high_color_hl = "term=standout cterm=bold ctermfg=199 ctermbg=16 gui=bold guifg=#F92672 guibg=#232526"

  • Set the background color:
    :let s:background_hl = "guifg=#999999 guibg=#323232 gui=NONE"

You can set the limits for the complexity indication with the following commands in your .vimrc:

  • Set the limit to switch to a medium complexity:
    :silent exe "let g:flog_medium_limit=10"

  • Set the limit to switch to a high complexity:
    :silent exe "let g:flog_high_limit=20"

You can hide some levels of complexity:

  • Hide low complexity:
    :silent exe "let g:flog_hide_low=1"

  • Hide medium complexity:
    :silent exe "let g:flog_hide_medium=1"

You can also turn flog off and on:

  • Turn on flog :call EnableFlog()

  • Turn off flog :call DisableFlog()

  • Toggle flog :call ToggleFlog()

Additionally, you can map this in your .vimrc: :map ,f :call ToggleFlog()<cr>


@garybernhardt's pycomplexity.vim.

@topfunky's rubycomplexity.el

@skammer's Ruby Cyclomatic Complexity Plugin