[r6rs-discuss] Records simplification/question
sperber at informatik.uni-tuebingen.de
Sun Nov 19 13:36:15 EST 2006
AndrevanTonder <andre at het.brown.edu> writes:
> - On p.67, it is not quite explained what happens if
> "parent-constructor-descriptor" is #f. The document states:
> "If rtd is an extension of another record type
> parent-rtd, parent-constructor-descriptor must be
> a constructor descriptor of parent-rtd or #f. If
> parent-constructor-descriptor is #f, a default constructor
> descriptor is supplied. In this case, p is a procedure that
> accepts the same number of arguments as the constructor
> of parent-constructor-descriptor ....."
> but the last phrase "the constructor of parent-constructor-descriptor"
> has no meaning here, if "in this case" refers to the case where
> "parent-contructor-descriptor" is #f, which the sentence seems to imply.
> I don't think that this was the intent, but this is the way it reads.
> In any case, I can't quite figure out from the prose what the default
> parent constructor descriptor is supposed to be in the #f case.
I'll try to clarify. The default constructor is one that accepts as
many arguments as there are fields and initializes the fields to them.
Cheers =8-} Mike
Friede, Völkerverständigung und überhaupt blabla
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