Bdtyk

I'm looking for a word for the following situation:

1. You have some sort of technical widget, e.g., a function in some programming library or some sort of interface on an appliance.




2. You want to describe the exact behavior of that widget, in general or in some particular instance. Perhaps you want to reference some particular fact about the behavior, or you just want to reference the general existence of a specification.




3. This word would be particularly useful where the widget solves a problem easily describable at a high level but the specific implementation could conceivably work in any of a variety of manners, and the choice of the exact behavior is a matter of convention.

Example sentences:

• "The FOO of this filter is that the whitelist overrides the blacklist, rather than the blacklist taking precedence over the whitelist."


• "The FOO of this phone is that it will use Wi-Fi if available and fall back to cellular data, even if the cellular signal is stronger than the Wi-Fi signal."


• "The FOO of all the regexp operators is to match greedily unless you add a '?' modifier."


• "The FOO of the argparse library is to assume that two tokens starting with hyphens are two flags rather than a flag and the argument for the flag."


• "Are the assumptions of function f compatible with the FOO of function g? I see a few calls to g before f in the main loop and I think g has some side effects on the global state that could be relevant."

"Behavior", "functionality", "logic", "semantics", "specification", "guarantee(s)", and "protocol" all come to mind.

"Behavior" works for all of the above examples but it's pretty vague. "Functionality" is also vague and more appropriate for referring to the uses of some widget rather than the details of using it in practice.

"Logic" and "semantics" seem close to what I want; I think I've seen "logic" used in this sense and may have seen "semantics" used in the same sense, but "logic" is again very general and vague, and I think "semantics" might not quite fit (certainly the linguistic sense is completely different).

"Specification", "guarantees" and "protocol" are basically what I want but they're only really usable in particular cases. "Specification" works for describing the functionality as a whole but not for describing the behavior in a particular edge case. The same goes for "protocol" (and it's sometimes defined to only apply to communication between two widgets). "Guarantees" only works for limited cases (it's either wrong or awkward in the first 3). It also has connotations of desirability and I want a more neutral term.

This hypothetical word would find a lot of use in contract programming, but I don't see a perfect fit in any words used in that context, so perhaps it just doesn't exist :(.