Chris@909: module CodeRay
Chris@909: module Encoders
Chris@909:   
Chris@909:   load :filter
Chris@909:   
Chris@909:   # A Filter that selects tokens based on their token kind.
Chris@909:   # 
Chris@909:   # == Options
Chris@909:   # 
Chris@909:   # === :exclude
Chris@909:   # 
Chris@909:   # One or many symbols (in an Array) which shall be excluded.
Chris@909:   # 
Chris@909:   # Default: []
Chris@909:   # 
Chris@909:   # === :include
Chris@909:   # 
Chris@909:   # One or many symbols (in an array) which shall be included.
Chris@909:   # 
Chris@909:   # Default: :all, which means all tokens are included.
Chris@909:   # 
Chris@909:   # Exclusion wins over inclusion.
Chris@909:   # 
Chris@909:   # See also: CommentFilter
Chris@909:   class TokenKindFilter < Filter
Chris@909:     
Chris@909:     register_for :token_kind_filter
Chris@909:     
Chris@909:     DEFAULT_OPTIONS = {
Chris@909:       :exclude => [],
Chris@909:       :include => :all
Chris@909:     }
Chris@909:     
Chris@909:   protected
Chris@909:     def setup options
Chris@909:       super
Chris@909:       
Chris@909:       @group_excluded = false
Chris@909:       @exclude = options[:exclude]
Chris@909:       @exclude = Array(@exclude) unless @exclude == :all
Chris@909:       @include = options[:include]
Chris@909:       @include = Array(@include) unless @include == :all
Chris@909:     end
Chris@909:     
Chris@909:     def include_text_token? text, kind
Chris@909:       include_group? kind
Chris@909:     end
Chris@909:     
Chris@909:     def include_group? kind
Chris@909:        (@include == :all || @include.include?(kind)) &&
Chris@909:       !(@exclude == :all || @exclude.include?(kind))
Chris@909:     end
Chris@909:     
Chris@909:   public
Chris@909:     
Chris@909:     # Add the token to the output stream if +kind+ matches the conditions.
Chris@909:     def text_token text, kind
Chris@909:       super if !@group_excluded && include_text_token?(text, kind)
Chris@909:     end
Chris@909:     
Chris@909:     # Add the token group to the output stream if +kind+ matches the
Chris@909:     # conditions.
Chris@909:     # 
Chris@909:     # If it does not, all tokens inside the group are excluded from the
Chris@909:     # stream, even if their kinds match.
Chris@909:     def begin_group kind
Chris@909:       if @group_excluded
Chris@909:         @group_excluded += 1
Chris@909:       elsif include_group? kind
Chris@909:         super
Chris@909:       else
Chris@909:         @group_excluded = 1
Chris@909:       end
Chris@909:     end
Chris@909:     
Chris@909:     # See +begin_group+.
Chris@909:     def begin_line kind
Chris@909:       if @group_excluded
Chris@909:         @group_excluded += 1
Chris@909:       elsif include_group? kind
Chris@909:         super
Chris@909:       else
Chris@909:         @group_excluded = 1
Chris@909:       end
Chris@909:     end
Chris@909:     
Chris@909:     # Take care of re-enabling the delegation of tokens to the output stream
Chris@909:     # if an exluded group has ended.
Chris@909:     def end_group kind
Chris@909:       if @group_excluded
Chris@909:         @group_excluded -= 1
Chris@909:         @group_excluded = false if @group_excluded.zero?
Chris@909:       else
Chris@909:         super
Chris@909:       end
Chris@909:     end
Chris@909:     
Chris@909:     # See +end_group+.
Chris@909:     def end_line kind
Chris@909:       if @group_excluded
Chris@909:         @group_excluded -= 1
Chris@909:         @group_excluded = false if @group_excluded.zero?
Chris@909:       else
Chris@909:         super
Chris@909:       end
Chris@909:     end
Chris@909:     
Chris@909:   end
Chris@909:   
Chris@909: end
Chris@909: end