Right, I would generally recommend against using `raise-syntax-error`
within syntax classes. syntax-parse has heuristics to convert the "most
specific" pattern failure into a syntax error, and it's usually better to
work within that framework (as your code using `~fail` does). To make that
work, yo
Fantastic, thank you for getting me on my way. I followed your advice where I
do not use string-producing expressions and ended up with a follow up question.
New syntax classes are below for those reading.
(define (unbounded? v)
(equal? "*" v))
(define-syntax-class racket-version-or-*
(pattern
Based on what you have written so far, the `versions` macro has no
sub-expressions, so you shouldn't use `expr/c` at all. It requires version
bounds to be in the form of literal strings. So you could describe the
macro using a grammar as follows:
Expression ::= | (versions Version ...)
Ve
Typos:
- "*" remove a bound ==> "*" removes a bound
- All examples should read (versions ...), not (version ...)
~slg
‐‐‐ Original Message ‐‐‐
On Wednesday, December 16, 2020 6:27 PM, Sage Gerard
wrote:
> I'm trying to learn how to write syntax classes. My intended macro expresses
>
I'm trying to learn how to write syntax classes. My intended macro expresses a
set of Racket versions, either as inclusive intervals or as exact versions. In
an interval, "*" remove a bound.
- (version "6.5") means exactly version "6.5", as does (version ("6.5" "6.5"))
- (versions ("7.0" "7.7.0
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