I’m working on adding support to the Galaxy framework for datatypes in the constructive solid geometry (CSG) space and I have several working Galaxy tools and a visualization plugin that deal with 3d shapes in this environment.  All of this work will soon be contributed to open source.

For one of the tools, I need to provide 2 select lists on the tool form that are associated in such a way that when an option in select list 1 is chosen, the options in select list 2 are altered and re-rendered.  This behavior would probably use a combination of dynamic options and refresh_on_change between the 2 associated select lists.

I’ve not seen a tool that does this precisely, so I’m hoping that if it is currently possible to do this within Galaxy tools, someone will point me to an example.

If it is not currently possible, I will contribute a PR for supporting it, but would like some input as to how it should be done.

Dynamic options are currently rendered using 4 approaches; from_file, from_dataset, from_parameter and from_data_table.  One or more of several filters can then be applied to the options to alter them if desired.  

Since these CSG tools involve new datatypes, I have flexibility into how the metadata elements are set up that are needed to render these 2 select lists.  A dictionary may work where the metadata element contents look like this:

{a: [‘1’, ‘2’], b: [‘3’, ‘4’] }

The options in select list 1 would be ‘a’ and ‘b’.  When ‘a’ is selected, select list 2 would have options ‘1’ and ‘2’, and when ‘b’ is selected, select list 2 would have options ‘3’ and ‘4’.

To support this approach, perhaps dynamic options could be enhanced to include a from_dict option.  There would be some complxity involved in associating the lists using refresh_on_change so that select list 2 is refreshed with the correct options when select list one is changed.  I haven’t yet worked out these details.

Also, using a dictionary will not keep order for the options, so perhaps a list of tuples would be better?

[ [ ‘a’, [‘1’, ‘2’]], [‘b’, [‘3’, ‘4’]]]

Can someone let me know if this is currently possible, and if so, an example tool that does it?  If it’s not possible, does the above approach seem reasonable, or is there a better way?

Thanks very much,

Greg Von Kuster