[R6RS] Unbound variables

Michael Sperber sperber at informatik.uni-tuebingen.de
Tue Mar 7 13:10:48 EST 2006

dyb at cs.indiana.edu writes:

>> This is referring to Will's classification of exceptional situations
>> that he just committed to the respository:
>> 4.1.1   reference to unbound variable  error       should &undefined
>> 5.2.1   set! (unbound variable)        error       should &undefined (!!!!!)
>> 5.2.1   set! (w/o defining)            unspecified should &undefined (!!!!!)
>> At least within a library module, I vote for turning these "should"s
>> into "must"s.
> I agree and would make one further change.  Within a library, there
> shouldn't be any unbound variables, just unbound identifiers, and an
> unbound identifier should be treated as a syntax error and cause a &syntax
> exception to be raised, since there's no way of knowing what kind of
> identifier it is and no reason for treating it as any particular kind.

Could you clarify the implications of this?  In particular, if I have

(syntax-rules (foo)

does `foo' (whose binding matters) need to be bound?

Cheers =8-} Mike
Friede, Völkerverständigung und überhaupt blabla

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