Re: Identifier equality of identifiers stashed in preserved syntax properties

As a small followup to this, I managed to come up with the following
hacky workaround, which seems to be working alright so far.
Specifically, it’s a function that converts arbitrary preservable values
into expressions that evaluate to themselves:

  (define preservable-property->expression
    (match-lambda
      [(and (app prefab-struct-key (? values prefab-key))
            (app struct->vector (vector _ fields ...)))
       #`(make-prefab-struct
          (quote #,prefab-key)
          #,@(map preservable-property->expression fields))]
      [(? list? lst)
       #`(list #,@(map preservable-property->expression lst))]
      [(cons a b)
       #`(cons #,(preservable-property->expression a)
               #,(preservable-property->expression b))]
      [(? syntax? stx)
       #`(quote-syntax #,stx)]
      [(and (or (? boolean?) (? symbol?) (? number?) (? char?)
                (? string?) (? bytes?) (? regexp?))
            datum)
       #`(quote #,datum)]
      [other
       (error
        'preservable-property->expression
        "disallowed value within preserved syntax property\n  value: ~e"
        other)]))

(That doesn’t currently handle all cases, like boxes/vectors/hash maps,
but it would be easy enough to extend.)

This is obviously a total hack, but it seems to work alright for this
particular case, and I thought I’d share it in case anyone else runs
into the same problem and this is helpful for them, too.

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