[r6rs-discuss] Transformer errors

From: AndrevanTonder <andre>
Date: Thu, 28 Jun 2007 13:10:54 -0400 (EDT)

There are some errors with regards to the draft treatment of the
concept of "transformer".

11.2.2 and 11.18 (this occurs three times in the document):

    "Implementation responsibilities: The implementation must check that the
     value of each <expression> is a transformer when the
     evaluation produces a value."

This is undecidable. It is also in direct conflict with 12.3, which says
(emphasis mine)

   "... a binding for a syntactic keyword must be an expression that evaluates
    to a transformer. (This is only the *user's* responsibility ...."

9.0.2 p 29:

   "the syntax-case form, described in library chapter 12,
    creates transformers ..."

This is obviously wrong - the procedure that defines the transformer
might or might not /contain/ a syntax-case form, but the syntax-case form,
if present, is not the creator of the transformer.

Andre
Received on Thu Jun 28 2007 - 13:10:54 UTC