indexing
	description: 
		"AST representation of a feature clause structure."
	date: "$Date$"
	revision: "$Revision $"

class
	FEATURE_CLAUSE_AS

inherit
	AST_EIFFEL
		redefine
			is_equivalent, location
		end

feature {AST_FACTORY} -- Initialization

	initialize (c: like clients; f: like features; l: like location) is
			-- Create a new FEATURE_CLAUSE AST node.
		require
			f_not_void: f /= Void
			l_not_void: l /= Void
		do
			clients := c
			features := f
			location := clone (l)
		ensure
			clients_set: clients = c
			features_set: features = f
			location_set: location.is_equal (l)
		end

feature -- Visitor

	process (v: AST_VISITOR) is
			-- process current element.
		do
			v.process_feature_clause_as (Current)
		end

feature -- Attributes

	clients: CLIENT_AS
			-- Client list

	features: EIFFEL_LIST [FEATURE_AS]
			-- Features

	location: TOKEN_LOCATION
			-- Position after feature keyword

	comment (class_text: STRING): STRING is
			-- Extract first line of comments on `Current' from `class_text'.
		require
			class_text_not_void: class_text /= Void
		local
			end_pos, real_pos: INTEGER
			retried: BOOLEAN
		do
			if not retried then
				real_pos := class_text.substring_index ("--", end_position)
				if real_pos /= 0 then
					if not features.is_empty then
						end_pos := features.first.start_position
					end
					if end_pos = 0 or else real_pos < end_pos then
						Result := class_text.substring (real_pos + 2, class_text.index_of ('%N', real_pos) - 1)
						Result.prune_all_leading (' ')
					else
						create Result.make (0)
					end
				else
					create Result.make (0)
				end
			else
				create Result.make (0)
			end
		ensure
			not_void: Result /= Void
		rescue
				-- `Position' might not be up-to-date, so that we may look after the end of the file.
			retried := True
			retry
		end

feature -- Comparison

	is_equivalent (other: like Current): BOOLEAN is
			-- Is `other' equivalent to the current object ?
		do
			Result := equivalent (clients, other.clients) and
				equivalent (features, other.features)
		end

feature -- Access

	feature_with_name (n: STRING): FEATURE_AS is
			-- Feature ast with internal name `n'
		local
			saved: INTEGER
		do
			saved := features.index
			from
				features.start
			until
				features.after or else Result /= Void
			loop
				Result := features.item.feature_with_name (n)
				features.forth
			end
			features.go_i_th (saved)
		end

	has_feature (f: FEATURE_AS): BOOLEAN is
			-- Does `f' appear in current feature clause?
			--| Based on `object_comparison' of EIFFEL_LIST,
			--| which is a reference comparison.
		local
			saved: INTEGER
			name: STRING
		do
			saved := features.index
			name := f.feature_name
			from
				features.start
			until
				features.after
			loop
				if features.item.feature_name.is_equal (name) then
					Result := True
					features.finish
				end
				features.forth
			end
			features.go_i_th (saved)
		end

	has_feature_name (n: FEATURE_NAME): BOOLEAN is
			-- Does `n' appear in current feature clause?
		local
			saved: INTEGER
		do
			saved := features.index
			from
				features.start
			until
				features.after or else Result
			loop
				Result := features.item.has_feature_name (n)
				features.forth
			end
			features.go_i_th (saved)
		end

	has_same_clients (other: like Current): BOOLEAN is
			-- Does this feature clause have the same clients
			-- as `other' feature clause?
		do
			Result := clients = Void and other.clients = Void

			if not Result then
				if clients /= Void then
					if other.clients /= Void then
						Result := clients.is_equiv (other.clients)
					else
						Result := False
					end
				end
			end
		end

	has_equiv_declaration (other: like Current): BOOLEAN is
			-- Has this feature clause a declaration equivalent to `other' 
			-- feature clause? i.e. `feature {CLIENTS}'
			--| NB: The comments are NOT considered for the moment, since 
			--| comments are not an attribute, but are to be retrieved from 
			--| the file that contains the source code.
		do
			if other = Void then
				Result := False
			else
				Result := has_same_clients (other)
					--| To be fixed to take comments into account
			end
		end

	is_equiv (other: like Current): BOOLEAN is
			-- Is `other' feature clause equivalent to Current?
		require
			valid_other: other /= Void
		do
			Result := 
				equivalent (clients, other.clients) and then
				equivalent (features, other.features)	
		end
--feature {CLASS_AS} -- Element change
--
--	--| NB: Since fixed structures are used, the following operations
--	--| are generally very expensive...
--
--	add_feature (new_f: FEATURE_AS) is
--			-- Add `new_f' at end of Current of feature clause 
--			--| (easier for offsets)
--		require
--			new_f_exists: new_f /= Void
--		local
--			saved, feat_count, i, new_sp, new_ep: INTEGER
--			old_features: like features
--			feat: FEATURE_AS
--		do
--				--| Since `features' is an heir of FIXED_LIST,
--				--| it's impossible to directly add an element...
--				--| Hence the following rather inefficient algorithm:
--			saved := features.index
--			old_features := features
--			feat_count := old_features.count
--			!! features.make_filled (feat_count + 1)
--			from
--				i := 1
--			until
--				 i > feat_count
--			loop
--				feat := old_features.i_th (i)
--				features.put_i_th (feat, i)
--				i := i + 1
--			end
--			new_sp := feat.end_position
--				--| beginning of new feature is the end of the previous one
--			new_ep := new_f.end_position - new_f.start_position + new_sp
--			new_f.update_positions (new_sp, new_ep)
--			features.put_i_th (new_f, i)
--			features.go_i_th (saved)
--	end
--
--	remove_feature (f: FEATURE_AS) is
--			-- Remove feature `f' from Current feature clause.
--		require
--			f_exists: f /= Void
--			has_f: features.has (f)
--		local
--			old_features: like features
--			saved, i, feat_count, offset: INTEGER
--			feat: FEATURE_AS
--		do
--			saved := features.index
--			old_features := features
--			feat_count := old_features.count
--			!! features.make_filled (feat_count - 1)
--			from
--				i := 1
--				feat := old_features.first
--			until
--				feat = f
--			loop
--				features.put_i_th (feat, i)
--				i := i + 1
--				feat := old_features.i_th (i)
--			end
--			from
--				offset := - (f.end_position - f.start_position + 4)
--					--| feature size + 1 semicolumn + 2 new lines
--				i := i + 1
--			until
--				i > feat_count
--			loop
--				feat := old_features.i_th (i)
--				feat.update_positions_with_offset (offset)
--				features.put_i_th (feat, i - 1)
--				i := i + 1
--			end
--			if features.valid_cursor_index (saved) then
--				features.go_i_th (saved)
--			end
--		end
--
--	replace_feature (old_f, new_f: FEATURE_AS) is
--			-- Replace feature `old_f' by feature `new_f'
--		require
--			old_f_exists: old_f /= Void
--			new_f_exists: new_f /= Void
--			has_old_f: features.has (old_f)
--		local
--			feat_count, i, offset, new_sp, new_ep: INTEGER
--			feat: FEATURE_AS
--		do
--			feat_count := features.count
--			from
--				i := 1
--			until
--				feat = old_f
--			loop
--				feat := features.i_th (i)
--				i := i + 1
--			end
--			new_sp := old_f.start_position
--			new_ep := (new_f.end_position - new_f.start_position) + new_sp
--			new_f.update_positions (new_sp, new_ep)
--			features.put_i_th (new_f, i - 1)
--			from
--				offset := new_f.end_position - old_f.end_position
--			until
--				i > feat_count
--			loop
--				feat := features.i_th (i)
--				feat.update_positions_with_offset (offset)
--				i := i + 1
--			end
--		end
--
--	update_positions_with_offset (offset: INTEGER) is
--			-- Add `offset' to the position information
--			-- of features belonging to Current feature clause.
--		local
--			feat_count, i: INTEGER
--			feat: FEATURE_AS
--		do
--			feat_count := features.count
--			from
--				i := 1
--			until
--				i > feat_count
--			loop
--				feat := features.i_th (i)
--				feat.update_positions_with_offset (offset)
--				i := i + 1
--			end
--		end

--feature {AST_EIFFEL} -- Output
--
--	simple_format (ctxt: FORMAT_CONTEXT) is
--			-- Reconstitute text.
--		local
--			comments: EIFFEL_COMMENTS
--		do
--			ctxt.put_text_item (ti_Feature_keyword)
--			ctxt.put_space
--			if clients /= Void then
--				ctxt.set_separator (ti_Comma);
--				ctxt.set_space_between_tokens;
--				clients.simple_format (ctxt);
--			end
--			comments := ctxt.eiffel_file.current_feature_clause_comments;
--			if comments = Void then
--				ctxt.new_line
--			else
--				if comments.count > 1 then
--					ctxt.indent
--					ctxt.indent
--					ctxt.new_line
--					ctxt.put_comments (comments)
--					ctxt.exdent
--					ctxt.exdent
--				else
--					ctxt.put_space;
--					ctxt.put_comments (comments)
--				end
--			end
--			ctxt.new_line;
--			ctxt.indent;
--			ctxt.set_new_line_between_tokens;
--			ctxt.set_separator (ti_Empty);
--			features_simple_format (ctxt);
--			ctxt.exdent;
--		end
--
--	features_simple_format (ctxt :FORMAT_CONTEXT) is
--			-- Reconstitute text.
--		local
--			i, l_count: INTEGER;
--			f: like features;
--			next_feat, feat: FEATURE_AS;
--			e_file: EIFFEL_FILE
--		do
--			f := features;
--			ctxt.begin;
--			e_file := ctxt.eiffel_file;
--			from
--				i := 1;
--				l_count := f.count;
--				if l_count > 0 then		
--					feat := f.i_th (1)
--				end
--			until
--				i > l_count
--			loop
--				ctxt.new_expression;
--				if i > 1 then
--					ctxt.put_separator;
--				end
--				ctxt.new_expression;
--				ctxt.begin;
--				i := i + 1;
--				if i > l_count then
--					e_file.set_next_feature (Void);
--				else
--					next_feat := f.i_th (i);
--					e_file.set_next_feature (next_feat);
--				end
--				e_file.set_current_feature (feat);
--				feat.simple_format (ctxt);
--				feat := next_feat;
--				ctxt.commit;
--			end
--			ctxt.commit;
--		end

end -- class FEATURE_CLAUSE_AS