Lets start with our simple set card 'Set+*type'.  It is an instance of a particular pattern that is connected in code.  Currently, it is defined in this file: mod/01_core/set_pattern/03_type.rb

def label name
  %{All "#{name}" cards}
end

def prototype_args anchor
  { :type=>anchor }
end

def pattern_applies? card
  !!card.type_id
end

def anchor_name card
  card.type_name
end

def anchor_id card
  card.type_id
end

The codename of *type is 'type', and is actually referenced by the filename itself.  Note how the codename appears in the generated version of the above file, in the header as Card::SetType and in the footer as register 'type' ... :

# -*- encoding : utf-8 -*-
class Card::TypeSet < Card::SetPattern
  cattr_accessor :options
  class << self
# ~~~~~~~~~~~ above autogenerated; below pulled from .../mod/01_core/set_pattern/03_type.rb ~~~~~~~~~~~

def label name
  %{All "#{name}" cards}
end

def prototype_args anchor
  { :type=>anchor }
end

def pattern_applies? card
  !!card.type_id
end

def anchor_name card
  card.type_name
end

def anchor_id card
  card.type_id
end


# ~~~~~~~~~~~ below autogenerated; above pulled from .../mod/01_core/set_pattern/03_type.rb ~~~~~~~~~~~
  end
  register "type", (options || {})
end

The module defines class methods on Card::TypeSet which inherits from Card::SetPattern.  This pattern has an anchor, which in the example is the card 'Set', which should be a cardtype card.  The card being passed in to anchor_id and anchor_name is the card being tested for membership in the set, and they return values that match the id/name of the pattern anchor (the Set card in the example).

Some sets don't have an anchor, they are global sets like *all or *rstar where we don't have any card parameters to the set.  In that case, you do not define anchor_name or anchor_id.  Here is an example:

file: .../set_pattern/04_star.rb

def label name
  'All "*" cards'
end

def prototype_args anchor
  { :name=>'*dummy' }
end

def pattern_applies? card
  card.cardname.star?
end

Here all the work is in pattern_applies?  This will be Card::StarSet and register as the 'star' pattern bound to the '*star' Set card.

This is the list of currently standard patterns:

• *all                                     All Cards
• *plus                                   All plus cards (name is not simple?)
• *star                                   All with names beginning with *
• *rstar                                  All cards with rightmost part (tag) beginning with *
• Type+*type                         All cards with type of 'Type'
• tag+*right                           All cards with tag of 'tag'
• Type+tag+*type_plus_right  All cards whose left part has type 'Type' and has tag of 'tag'
• Any+Card+*self                   Just this card (Any+Card)

There are many other possible patterns and most of them are very simple to add.