[Larceny-users] Ticket 638

[Lynn Winebarger]

On Tue, Apr 21, 2009 at 9:19 AM, Andre van Tonder <andre at het.brown.edu> wrote:
> This is a concious design choice in the implementation of FREE-IDENTIFIER=?
> The fact that this code does not work in Larceny shows that the code is not
> R6RS-compliant.  That it works in PLT and Ikarus just shows that their
> implementors chose not to worrry about imposing R6RS portability for reasons
> of their own.

Andre,
It seems to me that you are describing a restriction on valid inputs to your
implementation of free-identifier=?, rather than a pure instance of ill-formed
syntax.  Please consider changing the exception to have condition type
&assertion as per Section 5.4 instead of &syntax.

The R6RS is obviously ambiguous on this point by allowing identifier reference
errors to be signaled whenever or not at all, but this does not appear to be
a "real" instance of an identifier reference.  If nothing else,
changing the condition
type would clarify to the programmer getting the error that the exception is
occuring at run-time (for the library) and that the identifier is being
considered as a bare object rather than as part of a source expression.

Lynn