I know that I can use hyphens to suspend compounds that are written with a hyphen to begin with, for example "first-class fares and second-class fares" can be written as "first- and second-class fares".
But what about compound nouns that consist of two nouns and are not originally hyphenated, for example "PDF files and Excel files"? I can see two possible answers:
- "PDF- and Excel files"
- "PDF and Excel files"
I think that option 1 is more logical, because option 2 can lead to ambiguous expressions quite often. For example, "I like chocolate and vanilla ice cream" could mean that I like chocolate ice cream and vanilla ice cream, or that I like vanilla ice cream and chocolate. If the rule were to mark the omission of the word "files" by a hyphen, such ambiguity would be avoided. But I was not able to find any definite rules or style guides confirming this. All I can find are style guides that discuss compounds that were already hyphenated before they were suspended, like in my initial example.