11.6 Local Binding with Splicing Body
Like
let,
letrec,
let-values,
letrec-values,
let-syntax,
letrec-syntax,
let-syntaxes,
letrec-syntaxes,
letrec-syntaxes+values, and
local, except that in a
definition context, the body forms are spliced into the enclosing
definition context (in the same way as for
begin).
Examples: |
|
> o |
1 |
> one |
reference to undefined identifier: one |
When a splicing binding form occurs in a top-level context or
module context, its local bindings are treated similarly to
definitions. In particular, if a reference to one of the splicing
form’s bound variables is evaluated before the variable is
initialized, an unbound variable error is raised, instead of the
variable evaluating to the undefined value. Also, syntax bindings are
evaluated every time the module is visited, instead of only
once during compilation as in let-syntax, etc.
Example: |
|
reference to undefined identifier: bad.3 |
Note that require transformers and provide transformers are not
affected by syntax parameterization. While all uses of require and
provide will be spliced into the enclosing context, derived import or
export specifications will expand as if they had not been inside of the
splicing-syntax-parameterize.