Derive structured patterns for referrer at schema compilation time

[eecavanna]

Currently, structured patterns are hard-coded at both the reference source (some slots) and the reference target (the id slot of some class). This creates an opportunity for the two to fall out of sync.

I propose only defining them at the reference target, and not at the reference source; and then, programmatically constructing the pattern for the reference source at schema compilation time.

The algorithm (in pseudocode) I have in mind is:

# Combine sub-patterns into a single pattern, with "OR" operators.
existing_pattern = ""
for target_class_definition in range:
    target_class_id_pattern = target_class_definition.id_slot_definition.pattern
    existing_pattern = f"{existing_pattern}|{target_class_id_pattern}"

source_slot_definition.pattern = existing_pattern

CC: @turbomam

[eecavanna]

During today's metadata meeting, several team members expressed concerns about this approach: It depends upon the range defined on the referring slot being accurate and specific (i.e. sufficiently constrained).

CC: @aclum and @kheal

Example issue about a range not being properly constrained:

• make slot usage range match structured syntax patterns  #2238

I said that I may prototype it and demonstrate it to the group.