feature: build groups

See docs and changelog for more details on how these work.

lib/squib/api/groups.rb

@@ -0,0 +1,47 @@
+require 'set'
+
+module Squib
+
+  # An idea for later...
+  # def enable_group_env group
+  #   ENV['SQUIB_BUILD'] ||= ''
+  #   ENV['SQUIB_BUILD'] += ','
+  #   ENV['SQUIB_BUILD'] += group
+  # end
+  # module_function :enable_group_env
+
+  class Deck
+
+    # See official API docs
+    def group grp = :all, &block
+      raise 'Please provide a block' unless block_given?
+      block.yield if groups.include? grp
+    end
+
+    # See official API docs
+    def enable_group grp
+      groups # make sure it's initialized
+      @build_groups << grp
+    end
+
+    # See official API docs
+    def disable_group grp
+      groups # make sure it's initialized
+      @build_groups.delete grp
+    end
+
+    # See official API docs
+    def groups
+      @build_groups ||= Set.new.add(:all)
+    end
+
+    # See official API docs
+    def enable_groups_from_env!
+      return if ENV['SQUIB_BUILD'].nil?
+      ENV['SQUIB_BUILD'].split(',').each do |grp|
+        enable_group grp.strip.to_sym
+      end
+    end
+
+  end
+end

lib/squib/deck.rb

@@ -69,6 +69,7 @@ module Squib
       @height        = Args::UnitConversion.parse height, dpi
       cards.times{ |i| @cards << Squib::Card.new(self, @width, @height, i) }
       @layout        = LayoutParser.load_layout(layout)
+      enable_groups_from_env!
       if block_given?
         instance_eval(&block) # here we go. wheeeee!
       end
@@ -102,6 +103,7 @@ module Squib
     ##################
     require_relative 'api/background'
     require_relative 'api/data'
+    require_relative 'api/groups'
     require_relative 'api/image'
     require_relative 'api/save'
     require_relative 'api/settings'