On Nov 7, 5:09 pm, James Reeves <[EMAIL PROTECTED]> wrote:
> On Nov 7, 9:32 pm, Chouser <[EMAIL PROTECTED]> wrote:
>
> > > And in which case, your vector syntax could be misleading, because it
> > > seems to imply you're assigning i to 10:
>
> > > (dotimes [i 10]
> > > (prn i))
>
> > Vectors are also used for "for":
>
> > (for [i (range 10)]
> > (* 2 i))
>
> > Here i is not bound to the seq (range 10) but to each of the numbers
> > in turn.
>
> I'm still not convinced on this one. Currently, you have single
> assignments, where a value is assigned to a symbol as in let and
> binding, and sequence assignments, where each item in the sequence is
> assigned to a symbol. Adding a vector to dotimes would add a third
> type, and I don't think it's obvious what the [i 10] does. I mean, you
> originally put it down as [i (range 10)], so you were thinking in
> terms of [symbol sequence] too.
>
The general idea behind this patch is that all macros that introduce
names will do so in vector syntax. The nature of the bindings is going
to be open, as is the set of macros - doseq/dotimes/let/loop all have
different semantics. As it stands, it is confusing for people because
they don't know if they need a vector or not, for each macro.
> > > Second, with your patch, is the following valid:
>
> > > (doseq [i (range 10)
> > > j (range 10)]
> > > (prn i)
> > > (prn j))
>
> > It behaves the same as "for" does, that is with j in an inner loop.
> > It also supports :while and :when as "for" does.
>
> Well, not that my opinion matters ;) - but you've sold me on this one.
> Consistency with the for macro seems reasonable.
>
This is a much-needed enhancement, as so many people use for for side-
effects and forget dorun. Plus it will be faster for that use.
> > My first inclination is to disallow it -- add a check to make sure
> > only one binding pair is given. Alternatively it could act as if it
> > were nested, as "for" (and now "doseq") do, in which case it would act
> > like an "and", and both x and y would be bound to non-false values.
>
> Hm. A nested if would be consistent with the nested for and doseq
> macros. If this is implemented, nesting ifs would be my preference for
> this.
>
I'd like to see this patch limit its enhancements to "doseq a la for",
and otherwise just be a syntax change for all the others.
Rich
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