NAME
	function_exists - find out if a named function is defined in an
			  object and return the object filename.

SYNOPSIS
	string function_exists(string func, object ob)

DESCRIPTION
	This function searches for a named function `func' in the specified
	object `ob'. If it is found, the filename of that object is returned.

	The filename returned is not the same as the string returned by
	the function `file_name()', it does not have the instance number
	of the found object suffixed to it.

	If no argument `ob' is given, `this_object()' is used by default.

NOTA BENE
	It is the filename of the object that contains the function that
	is returned, not the composite object that might inherit the file
	that contains the function.

	E.g: if the function is in an object inherited by `ob' the
	     filename of the inherited object.

SEE ALSO
	inherit_list
