CHICKEN Scheme

Metadata

Id: a51778c8baaac8123b8f10059d84c17515fcddd8
Trac id: 387
Type: enhancement
Reporter: ashinn
Owner:
Cc:
Status: closed
Component: expander
Estimated difficulty:
Resolution: worksforme
Priority: minor
Milestone: 4.9.0
Version: 4.6.x
Changetime: 2012-09-24 21:47:48 UTC
Created: 2010-09-15 16:03:31 UTC
Keywords:

Description

Currently when you import from a module which hasn't been required yet you get runtime warnings, like:

 Warning: the following toplevel variables are referenced but unbound:
   json#json-write (in json-write)
   json#json-write (in json-write)

For implementing autoload it would be convenient to be able to suppress this warning, such as with

 (import-without-warning <import-spec>)

 (import-unbound <import-spec>)

Changes and comments

[2010-09-18 13:12:01 UTC] felix changed priority from major to minor

[2010-09-18 13:12:01 UTC] felix removed owner

[2010-09-18 13:12:01 UTC] felix changed component from unknown to expander

[2010-09-18 13:12:01 UTC] felix wrote:

Here is a proposal for a solution:

 (define-for-syntax unbound-in-eval '())
 
 (define-syntax without-warnings
   (syntax-rules ()
     ((_ body ...)
      (begin
        (##core#elaborationtimeonly
 	(set! unbound-in-eval ##sys#unbound-in-eval))
        (begin body ...)
        (##core#elaborationtimeonly   ; returns undefined value
 	(set! ##sys#unbound-in-eval unbound-in-eval))))))

The use of those internal forms is somewhat ugly, but we must make sure that the code is evaluated at expansion time without side-effecting a potentially generated import-lib (which would contain forms inside `begin-for-syntax` expressions, something we don't want). Note the return value of `(void)` above.

The warnings are actually generated by the REPL, not by `import`.