Several years ago, there was a very popular song about a "One-Eyed, One-Horned, Flying Purple People Eater."
In the lyrics, the "line" of the character is "eating purple people," which suggests that the color of its food is purple, rather than the character itself, but the lyrics also say that the character won't eat the narrator because the narrator is "tough" rather than non-purple. Most visual depictions I see show a purple character (which could, of course, still restrict itself to a purple diet).
For that matter, to which noun do the other adjectives apply?
If the food is purple, is it also the food that's flying, one-horned, and/or one-eyed?
If a creature only eats one-eyed, one-horned, flying purple people, it'll probably go hungry. (There are one-eyed people, folks who play only a single instrument that would fit in the horns section of a musical group, and there are blue people, so there may be purple ones somewhere as well, but if all those adjectives must apply to the food that really restricts the diet.) The end of the song indicates that the character plays music "through the horn in his head" so "one-horned" appears to apply to the character rather than its prey.
Is there any general rule or guidance for figuring out which adjectives apply to which words in English?
I found an advice column which failed to answer the question. I even found a question here from the nonfictional realm about a "main plugin file line" in which one answer says "you would not normally encounter such a construct" and another which says "There is a clear grammar rule for this situation" but then "you can decide" about separability, and in a world of fiction, a lot is possible.
It seems perfectly possible that one would encounter adjectives and nouns in various combinations in fiction and it would be helpful to figure out how to parse that.
Best Answer
This song, which is meant to be funny plays on ambiguity. Understanding how the joke works means understanding pragmatics: how context affects meaning.
The "one-eyed, one-horned, flyin' purple people eater" is (of course) something that nobody has ever seen. We are told that it does have one eye and one horn, and it does fly. But there is ambiguity in whether it is a monster that eats people and is purple, or a monster that eats purple people. However since we know that people are not purple, the pragmatic interpretation is that the monster is purple, and it eats all kinds of people. We have no pragmatic expectation of the colour of monsters, so this is reasonable.
Having set up that expectation, the song writer turns it round:
So that is part of the joke. What we expect, pragmatically, is reversed. The song is written to be ambiguous. However, normally ambiguity is a bad thing (as it means you can be misunderstood). If the pragmatic understanding is likely to be the wrong interpretation there are ways of removing the ambiguity.
Punctuation can help "purple-people eater", or changing the word order "eater of purple people". Using a category word, eg "monster" can also help
This avoids the ambiguity (but also kills the joke).
There's another joke later on: the "horn" is a musical horn, not an animal's horn. Again the pragmatic expectation is reversed, for the sake of the joke.