better_errors.rb

editor = ENV['EDITOR']

mapping = {
  [:textmate, :txmt, :tm] => :textmate,
  [:sublime, :subl, :st] => :sublime,
  [:macvim, :mvim, :vim] => :macvim
}

mapping.each do |matches, value|
  matches.each do |m|
    if editor =~ /#{m.to_s}/
      BetterErrors.editor = value
    end
  end
end