Can't using unquote-splicing in define-pass

[Yoxem]

When make a pass that output a L0 type to type-checking, it can't use unquote-splicing but shows "unsaved editor:44:11: unquote-splicing: invalid pattern or template in: (unquote-splicing t*)

(675 4)". (in DrRacket ver. 6.11). The code is shown below:

 #lang racket

 (require nanopass/base)

 (define (variable? x)
  (symbol? x))

 (define (constant? x)
  (or
   (flonum? x)
   (integer? x)
   (boolean? x)))

 (define (datatype? x)
   (memq x '(int flo bool void)))

 (define-language L0
   (terminals
     (variable (x))
     (datatype (dt))
     (constant (c)))

    (Expr (e body)
     x
     c
     (lambda ([t* x*] ... ) e))
   (Type (t)
     dt
     (-> t* ... t)
   )
   )
  (define-pass type-inference : L0 (ast) -> (L0 Type) ()

  (type-infer : Expr (e) -> Type ()
     ; constant
   [,c (cond
           [(flonum? e) 'flo]
           [(integer? e) 'int]
           [(boolean? e) 'bool])]

    [,x 'int]
     [(lambda ([,t* ,x*] ... ) ,body)
      `(-> ,@t* int) ;FIXIT: unquote-splicing: invalid pattern or template in: (unquote-splicing t*)
     ]
     )
      (type-infer ast)

  )
 (type-inference l0)

However, when set the output to a general s-expression (L0 Type) -> * (), and Type () -> * (), the error will not be shown.

[akeep]

I’m not as sure about the racket version of the nanopass framework, since I handed maintenance of this off, but in the Chez Scheme version, the syntax you are looking for is `(-> ,t* … int) — essentially exactly the syntax you provided when you defined the language.

This is because there i not really any splicing happening here, instead when you defined the form (-> t … t) in the nanopass language, it created a record with two fields one to hold t, which is expected to be a list of type and one to hold t. The syntax looks like you are constructing lists, but the underlying representation is actually racket structs.

-andy:)

On February 25, 2021 at 3:43:03 PM, Chen, Chien-ting ( notifications@github.com) wrote:

When make a pass that output a L0 type to type-checking, it can't use unquote-splicing but shows "unsaved editor:44:11: unquote-splicing: invalid pattern or template in: (unquote-splicing t*)

(675 4)". (in DrRacket ver. 6.11).

`#lang racket

(require nanopass/base)

(define (variable? x) (symbol? x))

(define (constant? x) (or (flonum? x) (integer? x) (boolean? x)))

(define (datatype? x) (memq x '(int flo bool void)))

(define-language L0 (terminals (variable (x)) (datatype (dt)) (constant (c)))

(Expr (e body) x c (lambda ([t x] ... ) e)) (Type (t) dt (-> t* ... t) ) ) (define-pass type-inference : L0 (ast) -> (L0 Type) ()

(type-infer : Expr (e) -> Type () ; constant [,c (cond [(flonum? e) 'flo] [(integer? e) 'int] [(boolean? e) 'bool])]

[,x 'int] [(lambda ([,t ,x] ... ) ,body) `(-> ,@t int) ;FIXIT: unquote-splicing: invalid pattern or template in: (unquote-splicing t) ] ) (type-infer ast)

) (type-inference l0)However, when set the output to a general s-expression(L0 Type) -> (), and Type () -> () `, the error will not be shown.

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[Yoxem]

I was also told by a Racket user (@dannypsnl) that the syntax (that @akeep mentioned above) ,t … instead of `,@t` is that I want and I've found that it is true. I think that the issue can be closed. Thank you very much.