How to use the binding space?

Questions & Answers
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1

According to the racket reference,

A space’s scope is accessed indirectly by using make-interned-syntax-introducer...... The require and provide forms include support for bindings spaces through subforms like for-space and only-space-in. No other forms provided by the racket module bind or reference identifier in a specified space

So I first tried running this in the repl:

> (module t racket/base
    (require (for-syntax racket/base))
    (define-syntax (bind-in-space stx)
      (syntax-case stx ()
        ((_ i v)  
         #'(begin
             (define i v)
             (provide (for-space tmp i))))))
    (bind-in-space a 1))
string:9:17: provide: provided identifier is defined only outside the space
  at: a
  in: (provide (for-space tmp a))
 [,bt for context]

Then I rewrote the program in the light of the discription of make-interned-syntax-introducer procedure

> (module t racket/base
    (require (for-syntax racket/base))
    (define-syntax (bind-in-space stx)
      (syntax-case stx ()
        ((_ i v)
         (let ((add-space (lambda (i) ((make-interned-syntax-introducer 'tmp) i 'add))))
           (with-syntax ((i (add-space #'i)))  
             #'(begin
                 (define i v)
                 (provide (for-space tmp i))))))))
    (bind-in-space a 1))

The module form was evaluated successfully, fortunatelly. But after importing the module with (require (only-space-in tmp 't)), I failed to reference the identifier a

> a
a: undefined;
 cannot reference an identifier before its definition
  in module: top-level
 [,bt for context]
> (module->exports ''t)
'(((0 . tmp) (a ())))
'()

What can I do to repair it?
PS:

> (version)
"8.8.0.8"
2

You can create a macro ref-in-space that does the same thing as bind-in-space, but for referencing.

3

You might be interested in how Qi uses binding spaces to create (and permit creation of) Qi-specific macros.

4

Thank you very much. I'll try this.