As in “flip the off switch,” “press the go button,” and “close the shut off valve". They all feel intuitively like they have similar usages. Each one is a noun that’s modified by some sort of description of the state/what happens after you interact with it.
But as far as an analysis for a grammar, it seems like “the on switch” and “the off switch” would go together, and “the go button” and “start button” would maybe go together but be a different construction. I’m not sure about “shut off valve.”
Here’s what I found that the ERG actually does for each:
the off switch – parses, but @ebender wasn’t sure if it’s the construction one would expect
the on switch – doesn’t parse
the go button – doesn’t parse
the start button – parses as a compound noun, not sure if this is “correct” for the usage I’m talking about
the shut off valve – parses, but I can’t make out if this is “correct” for this case either
Relatedly, it does parse both “the off button” and “the on button” but it’s treating those as individual predicates (_on+button_n_1, _off+button_n_1).
Are the constructions I’m getting out for the ones that do parse correct for this type of usage?
This is a vexing construction for which there is not a consistent analysis in the ERG. Allowing any preposition+noun as a compositional compound to handle e.g. “on switch” would lead to unwanted ambiguity, and similarly for any verb+noun to analyze examples such as “go button”. As you observed, for a few frequently occurring examples such as “on button”, the ERG has a lexical entry that treats them as words with spaces (not compositional), and for now, we’ll just try to add more of these to the lexicon as they are encountered. For examples like “start button” where there is already a noun-noun compound analysis, the ERG does not add a non-compositional verb-noun word-with-spaces lexical entry. The existing analysis of “off switch” uses the adjective “off” with the negative sense of “an off day”, not the reading you want, so we’ll add lexical entries for “on switch” and “off switch” analogous to the existing one for “on button”. Note that “the on/off switch” is analyzed with an existing adjective lexical entry for “on/off”. Analogous to the special lexical entry for “vice” of “vice chair”, we’ll add a compounding multi-word entry for “shut off” to analyze “the shut off valve”, since the analysis you currently see has the meaning of a valve that has been shut off, not the reading you want. While it is clear that this piecemeal approach to the data you’ve exemplified is unsatisfying and doesn’t scale well, a better analysis is elusive.