Vanilla Rails Style

These conventions CONTRADICT standard Ruby style guides. They reflect production 37signals code.

Counter-Intuitive Patterns

Pattern	37signals Way	Standard Ruby Way
Conditionals	if/else	Guard clauses
Private indent	2 spaces under private	No indentation
Bang methods	Only with counterpart	Flag "dangerous" actions
Method order	Invocation sequence	Alphabetical

Expanded Conditionals (NOT Guard Clauses)

Prefer if/else. Guard clauses allowed ONLY at method start with 5+ line body.

# Good
def todos_for_new_group
  if ids = params.require(:todolist)[:todo_ids]
    @bucket.recordings.todos.find(ids.split(","))
  else
    []
  end
end

# Bad
def todos_for_new_group
  ids = params.require(:todolist)[:todo_ids]
  return [] unless ids
  @bucket.recordings.todos.find(ids.split(","))
end

Multiple guards → nested if/else. Convert return unless chains to nested conditionals that show complete logic flow.

Allowed exception:

def after_recorded_as_commit(recording)
  return if recording.parent.was_created?  # Guard at START, complex body below

  if recording.was_created?
    broadcast_new_column(recording)
  else
    broadcast_column_change(recording)
  end
end

Private Method Indentation

Indent 2 spaces under private. No newline after private.

class SomeClass
  def public_method
    # ...
  end

  private
    def helper_one
      # indented
    end

    def helper_two
      # indented
    end
end

Exception — module with ONLY private methods: mark private at top, blank line, no indent.

Method Ordering

Order by invocation sequence — callers before callees:

1. Class methods
2. initialize (first among instance methods)
3. Public methods
4. Private methods (ordered by call sequence)

class Builder
  def build
    prepare
    format
    output
  end

  private
    def prepare; end   # called first
    def format; end    # called second
    def output; end    # called third
end

Bang Methods

Only use ! when non-bang counterpart exists: save/save!, update/update!.

No counterpart → no bang. close not close!. archive not archive!.

Red Flags

If you're about to...	Do this instead
Add guard clauses	Use if/else
Remove private indentation	Indent under private
Add ! to method without counterpart	Use plain name
Alphabetize private methods	Order by invocation
Create a service object	Move logic to model

Self-Check

• if/else instead of guard clauses (except single guard at start with complex body)
• Private methods indented under private
• Methods ordered by invocation sequence
• Bang only on methods with non-bang counterpart