Multi condition case when

README.md

@@ -326,6 +326,54 @@ Translations of the guide are available in the following languages:
  end
  ```
 
+* <a name="multi-condition-case-when"></a>
+Put multiple when conditions on separate lines.
+Particularly where the conditions form long, complicated lines.
+<sup>[[link](#multi-condition-case-when)]</sup>
+
+ ```Ruby
+ # good
+
+ case token
+ when :star_op
+ stack.pop * stack.pop
+ when :minus_op, :minus_minus_op
+ also_calculate_that
+ stack.pop - stack.pop
+ when MyModule::SomeDomain::BETA_USERS,
+ MyModule::SomeDomain::INTERNAL_RELEASE
+ stack.pop + stack.pop
+ when :int_literal,
+ :some_complicate_explicit_name,
+ :graduate_borrowers_with_arms,
+ :str_interpolated 
+ token.value
+ end
+ ```
+
+ Though better control of primary domain references should be exercised, this style offers a solution for some 'in the wild' situations. It reads better than:
+
+ ```Ruby
+ # bad
+
+ case token
+ when :star_op
+ stack.pop * stack.pop
+ when :slash_op
+ stack.pop / stack.pop
+ when :minus_op, :minus_minus_op
+ also_calculate_that
+ stack.pop - stack.pop
+ when MyModule::SomeDomain::BETA_USERS, MyModule::SomeDomain::INTERNAL_RELEASE
+ stack.pop + stack.pop
+ when :int_literal, :some_complicate_explicit_name, :graduate_borrowers_with_arms, :str_interpolated 
+ token.value
+ end
+ ```
+
+ The 'bad' example also has the issue of cause the entire when line to diff when one of the conditions is changed or updated
+
+
 * <a name="indent-conditional-assignment"></a>
  When assigning the result of a conditional expression to a variable,
  preserve the usual alignment of its branches.