The next optional FIELD component is the IN_SUMMARY clause. This is used when we want the field displayed in the Summary Pane on the Frame Display and in the summary line when a protocol is collapsed in the main window of the Protocol Navigator. As already discussed, we use the summary line to show the most critical data in a layer, data that summarizes what the layer is doing. The keyword IN_SUMMARY is followed by the name of the Summary Pane column that we want the data to show up in and the default width in pixels for this column. In the Protocol Navigator, the column name is used as the label. Here is an example reprised from the FP decoder.
FIELD command_code (Fixed 1 Byte) (Table tableCommands) IN_SUMMARY "Command/Response" 150 "Command"
The user is free to change the width of any column by manually adjusting it on screen. Note that you can put the contents of more than field in the same Summary column. For example, we could put the Command and Response in the same Summary column.
FIELD command_code (Fixed 1 Byte) IF (FieldIs EqualTo 1) (Table tableCommands) IN_SUMMARY "Command/Response" 150 "Command"
FIELD response_code (Fixed 1 Byte) IF (FieldIs EqualTo 0) (Table tableCommands) IN_SUMMARY "Command/Response" 150 "Response"
There are two additional keywords that can be used in place of the IN_SUMMARY keyword. These restrict the summary line display to either just the Summary pane or just the Protocol Navigator.
IN_SUMMARY_ONLY - the field will appear only in the Summary pane on the Frame Display
IN_COLLAPSED - the field will appear only in the Protocol Navigator
If you used the SUMMARY_COLUMNS option at the top of your decoder, do not include the column_width field above. Including the column_width in this case will cause a syntax error when the decoder is loaded.