[racket-dev] P4P: A Syntax Proposal

From: Robby Findler (robby at eecs.northwestern.edu)
Date: Fri Jul 30 10:11:01 EDT 2010

Given SK's teaching goals of "all of these operators are really the
same" and Eli's (implicit?) goal of "lets get wider hacker-types
interested" perhaps the right thing is to have a special infix-like
mode that you can switch into with a keyword (ala what was discussed
earlier in this thread)? This would be a special purpose mode where
there is some simple rule that distinguishes infix operators from
prefix ones (perhaps something like Haskell's convention)?


On Fri, Jul 30, 2010 at 9:05 AM, Eli Barzilay <eli at barzilay.org> wrote:
> On Jul 30, Robby Findler wrote:
>> On Fri, Jul 30, 2010 at 4:05 AM, Eli Barzilay <eli at barzilay.org> wrote:
>> > IMO, this thing is missing the point (the usual "parens, ewww!"
>> > one), as long as it ignores infix.
>> Seems to me that this point directly contradicts one of Shriram's
>> design goals, namely showing that + is no more special than append
>> or one of your own functions.
> To make my point better: I think that this (treating them all the
> same) is exactly what makes people dislike it.  Whether the open
> paren appears before the function or after it, and whether you
> separate arguments by spaces or commas is a minor point that is easy
> to get adjusted too.  As an experiment, try these:
>  (< (^ x 2) (/ d 10))
>  <(^(x, 2), /(d, 10))
>  x^2 < d/10
> I obviously see the simplicity and elegance of the first.
> I can certainly see the point that makes people want the third.
> But the second looks like a mixed up version of the first, which makes
> it harder to follow (I actually wrote it "top-down" since it didn't
> make any sense otherwise).  So I don't see any advantages for the
> second -- *especially* through the eyes of the many people who
> complain about sexprs, and OTOH, I see a huge disadvantage (which
> might be just me not being used to the open paren shift and the comma,
> so if that cost goes away I'm left with a syntax that is redundantly
> incompatible with sexprs).
> And yes -- this is an arithmetic example, and most code is not
> arithmetic, still -- it's these places that bother me (and seem to
> bother others) most when it gets to sexpr syntax.  Avoiding infix
> altogether (and even SK's manifesto has just a comment about not using
> it) is IMO sticking your head in the sand, and makes the whole thing
> look like the N+1th step in a long series of amusing posts in various
> places that end up with no practical results besides a long discussion
> thread.
> --
>          ((lambda (x) (x x)) (lambda (x) (x x)))          Eli Barzilay:
>                    http://barzilay.org/                   Maze is Life!

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