Implement expression tools and non-data tool outputs. #7556
PR #6925 introduced a GUI for connecting non-data (e.g. integer, boolean, color, etc..) workflow input parameter to tool input parameters (the backend for this was originally added in #1306). That ideally was just the beginning of work toward using such values in structured ways in workflows.
I think these expressions will be maximally useful when paired with format 2 workflows once we allow users to load arbitrary tools (I make the case more in full here), but I outline important near term potential uses there as well.
Because there is always a checklist in my PR descriptions: