#
#--
# Copyright (c) 2006-2007, John Mettraux, OpenWFE.org
# All rights reserved.
# 
# Redistribution and use in source and binary forms, with or without 
# modification, are permitted provided that the following conditions are met:
# 
# . Redistributions of source code must retain the above copyright notice, this
#   list of conditions and the following disclaimer.  
# 
# . Redistributions in binary form must reproduce the above copyright notice, 
#   this list of conditions and the following disclaimer in the documentation 
#   and/or other materials provided with the distribution.
# 
# . Neither the name of the "OpenWFE" nor the names of its contributors may be
#   used to endorse or promote products derived from this software without
#   specific prior written permission.
# 
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
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# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
# POSSIBILITY OF SUCH DAMAGE.
#++
#
# $Id: definitions.rb 2725 2006-06-02 13:26:32Z jmettraux $
#

#
# "made in Japan"
#
# John Mettraux at openwfe.org
#

#require 'openwfe/rudefinitions'
require 'openwfe/expressions/flowexpression'
require 'openwfe/expressions/fe_sequence'


module OpenWFE

    #
    # The <process-definition> expression.
    #
    class DefineExpression < SequenceExpression

        is_definition

        names :define, :process_definition, :workflow_definition


        attr_accessor :body_fei, :eval_only

        #
        # Evaluates the definition, but doesn't apply its body, will 
        # simply return the body fei.
        #
        def evaluate (workitem)
            @eval_only = true
            apply workitem
            return @body_fei
        end

        #
        # Called at the end of the 'evaluation', the 'apply' operation on
        # the body of the definition is done here.
        #
        def reply_to_parent (workitem)

            return if @eval_only

            unless @body_fei
                super workitem
                return
            end

            fei = @body_fei
            @body_fei = nil

            store_itself()

            get_expression_pool.apply fei, workitem
        end

        protected

            def get_to_next_child

                next_fei = super

                return nil unless next_fei

                rawchild = get_expression_pool.fetch_expression next_fei

                unless rawchild.is_definition?
                    @body_fei = next_fei unless @body_fei
                    return get_to_next_child
                end

                exp_class = get_expression_map.get_class rawchild

                if exp_class == DefineExpression
                    get_environment()[rawchild.definition_name()] = next_fei
                    return get_to_next_child
                end

                #
                # our next child will simply get applied

                next_fei
            end
    end

end