what=process(0,0)

    what ~= /postscript/:i
	    if %POSTSCRIPT% = true
		cat
	    else build and execute gs command

		if gs exists, build command and execute, returning error
		    status if it fails.
		else
		    reject

	 ~= /pdf/:i
	    build and execute gs command (see above)

	 ~= /pcl/:i
	    if %PCL% = true
		cat
	    else
		reject

	 ~= /gif|jpg|bmp|<image formats>/:i
	    build and execute format->target command

	 ~= {forbidden objects}
	    reject

	 ~= text
	    if %HANDLE_TEXT%,
		%HANDLE_TEXT%
	    else if %TEXT% = true
		cat
	    else if %POSTSCRIPT% = true
		enscript
	    elif %default%
		%default%
	    else
		reject

	 default
	    if %PERMISSIVE% = true
		if %default%
		    %default%
		else
		    reject
	    else
		reject

