CWL Release 1.0: Why having both default and valueFrom fields on WorkflowStepInput?

Question

[Boris Burkov]

Hi, I am working on an implementation of CWL and I don't understand, why would WorkflowStepInput have 2 fields simultaneously: valueFrom and default: http://www.commonwl.org/v1.0/Workflow.html#WorkflowStepInput.

I understand that valueFromallows us to hard-code the value, supplied to a step input, or make it a dynamically evaluatable expression (if we don't want this step to take its input value from workflow input or output of another step). But why would I need default field then, except that it is a legacy field from the times of draft-2?

[Michael]

I have seen several CWL posts now, could somebody explain the relation to bioinformatics of the questions? I see that it is a very useful tool also for bioinformatics but not only, but some questions seem to be very much about the details of its implementation that are not at all bioinformatics specific.

[Michael R. Crusoe]

Lets discuss this elsewhere -- maybe create an issue at https://github.com/ialbert/biostar-central/issues & tag me? I'm mr-c on Github.

Answer 1

[Michael R. Crusoe]

This was answered on GitHub: https://github.com/common-workflow-language/common-workflow-language/issues/358#issuecomment-267011066

Your hypothesis that this is left over from draft-2 makes the most sense. I'll let @tetron and @ntijanic chime in with their perspectives.

I support marking as deprecated the use of valueFrom with a constant string (which should have been Any or CWLType) and for removal in v2.0 of this usage altogether..