A recent question asked about determining the "function" of a sentence, which to me isn't a concrete language construct the way that question implies. Seeking more information, I looked into the functions tag to see what else existed on this subject and found... a haphazard assortment of questions, most of which did not contain any relation I could recognize to the question I came from. Some sample concepts the tag referred to:
- Function of a sentence (e.g. Blame, Complaint)
- Function of words within a sentence (e.g. Subject, Direct Object)
- Mathematical function (Arguably off-topic in the first place)
- Phrase categorization (e.g. "fused determiner-head")
- Part of speech (e.g. noun, adjective)
As well as some cases where the lines between some of those are blurred.
It's possible that some or even most of these questions actually do have a common thread, or that the distinctions that I see aren't considered meaningful, but to me it seems that it's currently being used quite haphazardly and since it doesn't have any Usage Guidance it's hard to tell whether it is appropriate or not, or generally what sort of questions it should apply to.