Advanced XForm Recipes

[lognaturel]

#20 and #222 pull in some form design documentation that talks about raw XML. In general, this is not used much. However, there are some real cases in which it might be helpful.

Let's use this issue thread to collect those and to eventually add them to an existing document or create a new one.

Perform a complex calculation and show it to the user without introducing a new calculate field: https://forum.opendatakit.org/t/is-output-value-an-instance-node-or-xpath/10262/6

Iterate over a list of choices identified by a first question in a cascading select: https://forum.opendatakit.org/t/repeat-questions-depending-upon-selection/10033/8

Build a dynamic list of select choices based on previous form values: https://forum.opendatakit.org/t/generate-multiple-choice-alternatives-based-on-the-answer-of-a-previous-question/10269/4?u=ln

[adammichaelwood]

Perform a complex calculation and show it to the user without introducing a new calculate field: https://forum.opendatakit.org/t/is-output-value-an-instance-node-or-xpath/10262/6

Is that really something that requires XML-editing, since there is a "canonical" way of doing it in XLSForm (that is... using a calculate field)

[adammichaelwood]

Iterate over a list of choices identified by a first question in a cascading select: https://forum.opendatakit.org/t/repeat-questions-depending-upon-selection/10033/8

This also doesn't require editing the XML directly, does it? Just some complex knowledge of XML, but used inside XLSForm.

[adammichaelwood]

I've reframed this issue --

I'm working on a doc for Advanced XForm Recipes that will include so things that can be done in XLSForm and some things that requires XML editing, and this can be added to over time.

[lognaturel]

Outputting a value without introducing a new field can be important because it's harder to work with data columns that aren't useful. It makes data exports unnecessarily complicated.

Regarding iterating over choices identified by a cascading select question, you're right. I suppose that category is things that the XLSForm ${} syntax doesn't surface and that require XPath knowledge.

Advanced recipes sounds good.

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