rationales.md

Rationales

This document contains what are at times lengthy rationales and justifications for the decisions made in the main Style guide.

Table of Contents

1. Line Length

Line Length

Keeping code visually grouped together (as a 100-character line limit enforces) makes it easier to understand. For example, you don't have to scroll back and forth on one line to see what's going on -- you can view it all together.

Here are examples from our codebase showing several techniques for breaking complex statements into multiple lines that are all < 100 characters. Notice techniques like:

• liberal use of linebreaks inside unclosed ( { [
• chaining methods, ending unfinished chains with a .
• composing long strings by putting strings next to each other, separated by a backslash-then-newline.
• breaking long logical statements with linebreaks after operators like && and ||

scope = Translation::Phrase.includes(:phrase_translations).
  joins(:phrase_screenshots).
  where(:phrase_screenshots => {
    :controller => controller_name,
    :action => JAROMIR_JAGR_SALUTE,
  })

translation = FactoryGirl.create(
  :phrase_translation,
  :locale => :is,
  :phrase => phrase,
  :key => 'phone_number_not_revealed_time_zone',
  :value => 'Símanúmerið þitt verður ekki birt. Það er aðeins hægt að hringja á '\
            'milli 9:00 og 21:00 %{time_zone}.'
)

if @reservation_alteration.checkin == @reservation.start_date &&
   @reservation_alteration.checkout == (@reservation.start_date + @reservation.nights)

  redirect_to_alteration @reservation_alteration
end

<% if @presenter.guest_visa_russia? %>
  <%= icon_tile_for(I18n.t("email.reservation_confirmed_guest.visa.details_header",
                           :default => "Visa for foreign Travelers"),
                    :beveled_big_icon => "stamp") do %>
    <%= I18n.t("email.reservation_confirmed_guest.visa.russia.details_copy",
               :default => "Foreign guests travelling to Russia may need to obtain a visa...") %>
  <% end %>
<% end %>

These code snippets are very much more readable than the alternative:

scope = Translation::Phrase.includes(:phrase_translations).joins(:phrase_screenshots).where(:phrase_screenshots => { :controller => controller_name, :action => JAROMIR_JAGR_SALUTE })

translation = FactoryGirl.create(:phrase_translation, :locale => :is, :phrase => phrase, :key => 'phone_number_not_revealed_time_zone', :value => 'Símanúmerið þitt verður ekki birt. Það er aðeins hægt að hringja á milli 9:00 og 21:00 %{time_zone}.')

if @reservation_alteration.checkin == @reservation.start_date && @reservation_alteration.checkout == (@reservation.start_date + @reservation.nights)
  redirect_to_alteration @reservation_alteration
end

<% if @presenter.guest_visa_russia? %>
  <%= icon_tile_for(I18n.t("email.reservation_confirmed_guest.visa.details_header", :default => "Visa for foreign Travelers"), :beveled_big_icon => "stamp") do %>
    <%= I18n.t("email.reservation_confirmed_guest.visa.russia.details_copy", :default => "Foreign guests travelling to Russia may need to obtain a visa prior to...") %>
  <% end %>
<% end %>