[ANSI-Smalltalk] re: array creation syntax (was: expressing method signatures)

Tue Mar 25 01:51:46 GMT 2008

Eliot,

Really?  No semicolons?... Why?... I thought that from

Bezier2Segment>>ellipseSegments

  ^{all those 8 things}

one would have somewhere

<blablabla>
  someBezier2Segment ellipseSegments do: aBlock
<blablabla>

but then that would reduce to

Bezier2Segment>>ellipseSegmentsDo: aBlock

  aBlock
    value: seg1a;
    (etc)
    value: seg8a;
    value: seg8b

What did I miss here?

Andres.

On Mon, Mar 24, 2008 at 6:45 PM, Eliot Miranda <eliot.miranda at gmail.com>
wrote:

>
>
> On Mon, Mar 24, 2008 at 6:18 PM, Andres Valloud <andres.valloud at gmail.com>
> wrote:
>
> > Eliot,
> >
> > Re: the Bezier2Segment... if I remember correctly, the {} syntax creates
> > a literal at compile time.  Is that so?  Or is the array created every time
> > execution goes over {}?
> >
> > In the case of Bezier2Segment, what I think is at times missing from
> > consideration is what is usually done with such arrays... do: aBlock?
> > Because if so, it would be cheaper (and *sometimes* clearer) to do:
> >
> > Bezier2Segment>>ellipseSegmentsDo: aBlock
> >
> >   aBlock
> >     value: seg1a;
> >     value: seg1b;
> >     value: seg2a;
> >     value: seg2b;
> >     value: seg3a;
> >     value: seg3b;
> >     value: seg4a;
> >     value: seg4b
>
>
> Um, semicolons aren't what you mean.  You want a
> Closure>>value:value:value:value:value:value:value:value: method (right?),
> and there isn't one.  You have to use valueWithArguments:.  But there isn't
> even an ArrayedCollection class>>with:with:with:with:with:with:with:with:
> method to construct one with(*).  So once again a brace construct is the
> most convenient way to implement
> Closure>>value:value:value:value:value:value:value:value:.
>
> (*) at least you can write ArrayedCollection
> class>>with:with:with:with:with:with:with:with:.  You can't write
> Closure>>value:value:value:value:value:value:value:value:value: directly
> because it would be a primitive and either an 8-arg primitive may not be
> available or a varargs primitive may not accept more than 3 arguments.  If
> you write it in terms of valueWithArguments: you still need Array
> class>>with:with:with:with:with:with:with:with: to construct the argument
> vector (or of course the convenient brace construct).
>
> One could further wonder why are there so many of these seg* things
> > floating around...
>
>
> Because sometimes things come in octets...
>
> >
> >
> > Just my opinion though,
> > Andres.
> >
> >
> >
> > On Mon, Mar 24, 2008 at 6:09 PM, Eliot Miranda <eliot.miranda at gmail.com>
> > wrote:
> >
> > >
> > >
> > > On Sat, Mar 22, 2008 at 1:44 PM, Andres Valloud <
> > > andres.valloud at gmail.com> wrote:
> > >
> > > > I think something that is being left unaddressed is whether using
> > > > literal arrays that allow code expressions (e.g.: the brace syntax
> > > > in Squeak) is a good practice or not.  In my experience, I have not felt the
> > > > need for such things, but maybe I have not been exposed to particular
> > > > circumstances in which they become useful.  Does anybody have some slam dunk
> > > > examples that can be shared so that we can evaluate this better?
> > >
> > >
> > > Just open any recent Squeak image and broseer senders of #braceArray,
> > > e.g. the last line of
> > > Bezier2Segment>>makeEllipseSegments: aRectangle in Squeak V3.9 reads
> > >
> > >     ^{seg1a. seg1b. seg2a. seg2b. seg3a. seg3b. seg4a. seg4b}
> > >
> > > instead of
> > >     ^(Array with: seg1a with: seg1b with: seg2a with: seg2b),
> > >       (Array with: seg3a with: seg3b with: seg4a with: seg4b)
> > >
> > > BTW, the first example tat comes up in my image contains:
> > >     {'zip'.'sar'.'pr'. 'mcz'. '*'} includes: suffix
> > > which is better written as
> > >     #('zip' 'sar' 'pr' 'mcz' '*') includes: suffix
> > > so one can argue that it can be confusing for some to have two
> > > apparently similar constructs.  But in my experience {} carries its weight
> > > (and there's no doubt that #() does).
> > >
> > >
> > > >
> > > > Andres.
> > > >
> > > > On Tue, Mar 18, 2008 at 9:57 AM, Eliot Miranda <
> > > > eliot.miranda at gmail.com> wrote:
> > > >
> > > > > On Mon, Mar 17, 2008 at 2:11 PM, Craig Latta <craig at netjam.org>
> > > > > wrote:
> > > > >
> > > > > >
> > > > > >  > Defining new language elements is hard.  The worst that could
> > > > > > happen
> > > > > >  > to this project, is to have extremely long threads with no
> > > > > > conclusion
> > > > > >  > as on the Squeak list.
> > > > > >
> > > > > >      Indeed, although for what it's worth there's no lingering
> > > > > > debate
> > > > > > there on this particular issue[1]. ;)
> > > > > >
> > > > > >
> > > > > > -C
> > > > > >
> > > > > > [1]
> > > > > >
> > > > > >      Namely, the short form of...
> > > > > >
> > > > > >      Array with: #foo with: #bar
> > > > > >
> > > > > > is...
> > > > > >
> > > > > >      #(foo bar)
> > > > > >
> > > > > > as in Smalltalk-80, and the short form of...
> > > > > >
> > > > > >      Array with: #foo with: true
> > > > > >
> > > > > > is...
> > > > > >
> > > > > >      {#foo. true}
> > > > >
> > > > >
> > > > > Well, in Squeak 3.9 I get
> > > > >
> > > > > Welcome to the finale version of 3.9 of 7 of November 2006
> > > > > #(nil true false foo) collect: [:ea| ea class] {UndefinedObject .
> > > > > True . False . ByteSymbol}
> > > > > #(nil true false foo) printString '#(nil true false #foo)'
> > > > >
> > > > >      But I suspect the appropriate standard use of curly brackets
> > > > > > across multiple dialects is a whole other morass. :)
> > > > >
> > > > >
> > > > > Having been living with Squeak for a while now I really, really
> > > > > like the curly brace syntax.  I also note that it doesn't conflict with
> > > > > e.g. VisualWorks use of #{name} for binding references.  So I have
> > > > > a strong personal preference for it, but that's just personal.
> > > > >
> > > > >
> > > > >
> > > > > _______________________________________________
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> > > > >
> > > > >
> > > >
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