On 10/25/2016 08:04 PM, Alexis King wrote:
That makes sense; thank you for your quick reply. It might be
possible to do something like what you describe, but I do have a
little more context that makes this sort of tricky. I’m trying to
not just store identifiers but also store prefab structs containing
identifiers. The issue I’m running into is that embedding prefab
structs in syntax objects seems to “flatten” the contained syntax
objects. For example, if I do something like this:
(begin-for-syntax
(struct prefab-box (val) #:prefab)
(syntax-parse
(local-expand
#`(let-syntax ([x (λ (stx)
(syntax-property #'(void) 'prop
#,(prefab-box #'add1)))])
x)
'expression '())
#:literals [let-values]
[(let-values () (let-values () x))
(prefab-box-val (syntax-property #'x 'prop))]))
The result of this is not the syntax #'add1, but the symbol 'add1.
Consider that (eval (list 'quote #'+)) also evaluates to a symbol, for
about the same reason.
Try local-expanding either of these terms instead:
#`(let-syntax ([x (λ (stx)
(syntax-property #'(void) 'prop
(prefab-box #'add1)))])
x)
or
#`(let-syntax ([x (λ (stx)
#'#,(syntax-property #'(void) 'prop
(prefab-box #'add1)))])
x)
and the box will have an identifier in it.
Ryan
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