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Re: SRFI 105: Curly-infix-expressions

This page is part of the web mail archives of SRFI 105 from before July 7th, 2015. The new archives for SRFI 105 contain all messages, not just those from before July 7th, 2015.

On Tue, Aug 28, 2012 at 12:58 AM, Shiro Kawai <shiro@xxxxxxxx> wrote:
> From: Alan Manuel Gloria <almkglor@xxxxxxxxx>
> Subject: Re: SRFI 105: Curly-infix-expressions
> Date: Mon, 27 Aug 2012 15:58:36 +0800
>> The way the current spec is done allows for code like the
>> following:
>> (define {a // b}
>>   {(unwrap-par-monad a) parallel (unwrap-par-monad b)})
> Kind of cute, though I wonder if this can be extended
> to handle variable arity operators.

David A. Wheeler and me kinda considered the following

{ x a . y } => (a x . y)

The proposal was that the "list length" operation would
consider improper lists to be of size 1, so {x a . y} would
be considered an odd length, at least 3, etc. basically
triggering the "simple" rule.

>> (define-syntax o
>>   (syntax-rules ()
>>     ({a o b}
>>       (lambda (x) (b (a x))))
>>     ({a o b o rest o ...}
>>      {{a o b} o rest o ...})))
>> Again, this takes advantage of the fact that
>> {a o b o rest o ...} means (o a b rest ...)
> This is also cute, though it effectively changes the
> surface meaning of "x ...".
> These two examples are interesting.  They don't appeal to me
> enough to convince me non-macro approach is good, but others
> may feel differently.  How about including them in the rationale
> section to explain why reader transformation is necessary?
> --shiro

Yes, I probably should.