Refactor line length to rationales.md

This commit moves the bulk of our line length section over to `rationales.md`,
and adds a link in the main style guide.

Resolves #76

README.md

@@ -165,83 +165,10 @@ Airbnb also maintains a [JavaScript Style Guide][airbnb-javascript].
 
 ## Line Length
 
-Keep each line of code to a readable length. Unless you have a reason
-to, keep lines to fewer than 100 characters. 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 `||`
-
-
-```ruby
-scope = Translation::Phrase.includes(:phrase_translations).
-  joins(:phrase_screenshots).
-  where(:phrase_screenshots => {
-    :controller => controller_name,
-    :action => JAROMIR_JAGR_SALUTE,
-  })
-```
-
-```ruby
-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}.'
-)
-```
-
-```ruby
-if @reservation_alteration.checkin == @reservation.start_date &&
-   @reservation_alteration.checkout == (@reservation.start_date + @reservation.nights)
-
-  redirect_to_alteration @reservation_alteration
-end
-```
-
-```erb
-<% 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:
-
-```ruby
-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
-```
-
-```erb
-<% 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 %>
-```
+* Keep each line of code to a readable length. Unless
+  you have a reason to, keep lines to fewer than 100 characters.
+  ([rationale](./rationales.md#line-length))<sup>
+  [[link](#line-length)]</sup>
 
 ## Commenting
 

rationales.md

@@ -0,0 +1,83 @@
+# Rationales
+
+This document contains what are at times lengthy rationales and justifications
+for the decisions made in the main [Style guide](./README.md).
+
+## Table of Contents
+  1.  [Line Length](#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 `||`
+
+```ruby
+scope = Translation::Phrase.includes(:phrase_translations).
+  joins(:phrase_screenshots).
+  where(:phrase_screenshots => {
+    :controller => controller_name,
+    :action => JAROMIR_JAGR_SALUTE,
+  })
+```
+
+```ruby
+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}.'
+)
+```
+
+```ruby
+if @reservation_alteration.checkin == @reservation.start_date &&
+   @reservation_alteration.checkout == (@reservation.start_date + @reservation.nights)
+
+  redirect_to_alteration @reservation_alteration
+end
+```
+
+```erb
+<% 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:
+
+```ruby
+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
+```
+
+```erb
+<% 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 %>
+```