2000-05-03  Jody Goldberg <jgoldberg@home.com>

	* src/command-context.c (gnumeric_error_invalid) : new function.
	* src/command-context-gui.c (ccg_error_invalid) : Handle.
	* src/command-context-corba.c (ccc_error_invalid) : Handle.

	* src/commands.c (cmd_rename_sheet_{undo,redo}) : Pass a context to
	  workbook_rename_sheet.

	* src/workbook.c (workbook_rename_sheet) : Sheet names can not be
	  empty.  Take a CommandContext and report the error.  Invert the
	  return value.