Plural and Singular Parallelism
Let's consider the following example taken from C# Pocket Reference by Joseph Albahari.
Statements in C# execute sequentially and are terminated by a semicolon.
Why is the semicolon in singular form while there are some C# statements in the context? In my thinking, there must be one to one correspondence between a statement and a semicolon, so the semicolon must be in plural form. But if we do like this, the meaning becomes unclear if there is no code snippet provided.
Another example for those who does not know C#:
Visitors who come to my office must bring a cup to drink.
The speaker wants to say each visitor must bring one and only one cup; no more than one cup is allowed for a single visitor. But, one might think there is only one cup used in rotation among all visitors.
If we rephrase like the following,
Visitors who come to my office must bring cups to drink.
then the speaker's intent might be unclear as well.
So, how does one handle this kind of problem?
You've run afoul of the Plural Generic Noun Phrase, which is one of the variants of Generic reference in English.
It would be possible and allowable to use semicolons instead of a semicolon; but probably the singular is preferable because there is precisely one semicolon per statement, at precisely the same place in each case.
However, a better strategy would be to use the Indefinite Generic Noun Phrase a statement in C#, which is generic, and distributive, and also singular, so that the example would be
A statement in C# executes sequentially and is terminated by a semicolon.
This is better because indefinite generics are used to indicate definitional properties, and that's what's at issue here.
I think you're erring on the side of rigid application of rules over clarity.
That sentence is not unclear in its meaning in everyday usage. It's true that this would be an ambiguous sentence if you were in a Logic course, but common English parlance is not required to adhere to rules that are so strict.
Compare that sentence with other examples:
- Concert-goers require a wristband
- Dogs must be kept on a leash
- Cars have one engine
I don't find that the sentence "visitors come to my office must bring a cup to drink" has unclear intent. The idea that the visitors must bring a cup to drink, implies that there is one cup tied every visitor. That's why it's singular.
If the sentence said "visitors come to my office must bring two cups to drink," that would imply every visitor who comes to the office must bring two cups to drink, tying two cups each to every visitor.
But if you feel as though it's still unclear, the best way to make it conspicuous would be to use words that clearly indicate the kind of sentence you're trying to say.
In this case, try using words like "each" or "every":
"Visitors come to my office must bring a cup to drink"
- "Any visitor who comes to my office must bring a cup to drink
- "Visitors who come to my office must bring their own cup to drink
- "Each visitor who comes to my office must bring a cup to drink
With these kinds of words used, it becomes very clear that there is one cup tied to one visitor. It's the same idea with the semicolons in C#.
I can understand why you would feel the intent isn't clear. Using certain words as clear indicators though, may help with that.
Hope this helps!