[racket users] Macro literal "|"

[Kevin Forchione]

Hi guys,
I’ve been trying to figure out how to use “|” in a macro. I’ve got syntax like this in mind:

(foo A | B)

Not sure if I can do this because the reader expects a pair. If “|” isn’t a convenient literal to work with is there an alternative others have used that represents more or less the idea of “or” or “alternate”?

Thanks!

Kevin

[Philip McGrath]

You're right that `|` isn't a valid terminal with the normal reader, but, as it happens, the zero-length identifier can be written as `||`. (I don't think the concept of a zero-length identifier is common in other languages: it corresponds to the empty string.)

-Philip

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[Stephen Chang]

As mentioned, to get your macro to work, you have to change how the
reader behaves on "|".

You might be interested in the (implementation of) no-vert-bar reader lang:

https://docs.racket-lang.org/no-vert-bar-lang/index.html

On Mon, Feb 3, 2020 at 6:27 PM Kevin Forchione <lys...@gmail.com> wrote:
>