Re: [Bug-apl] Question about behavior of ⍋

[David B. Lamkins]

I think it'd be really handy if that expression did what we'd like it to
do. I guess it'd fall under the category of "conforming extension". 

Neither IBM nor ISO APL define a behavior for dyadic grade with other
than a character matrix as the right argument.

On Tue, 2014-07-08 at 12:40 +0800, Elias Mårtenson wrote:
> To clarify, I tried the following:
> 
> 
>       (⎕UCS¨⍳1114111) ⍋ 'foo' 'bar' 'test'
> DOMAIN ERROR
>       (⎕UCS¨⍳1114111)⍋'foo' 'bar' 'test'
>       ^              ^
> 
> 
> Note of course that this is pretty insane, and there should be an
> easier way to do this.
> 
> 
> Regards,
> Elias
> 
> 
> On 8 July 2014 12:38, Elias Mårtenson <address@hidden> wrote:
>         Right, but just having a "plain" collating order for Unicode
>         would require me to pass a million-element array
>         (⎕UCS¨⍳1114111) as left argument to grade.
>         
>         
>         That said, I can't even get dyadic grade to work at all, but
>         that's a separate issue.
>         
>         
>         Regards,
>         Elias
>         
>         
>         On 8 July 2014 12:27, David B. Lamkins <address@hidden>
>         wrote:
>                 The problem with generating a permutation vector for
>                 an "arbitrary"
>                 Unicode string is still a problems of collating order.
>                 There is no
>                 inherent order in Unicode; someone has to decide on
>                 what makes sense as
>                 a collating order for the subset of code points used
>                 by the application.
>                 
>                 You should use ⎕ucs with a vector of code points to
>                 define your own
>                 collating order for Unicode; any code points not
>                 explicitly specified in
>                 the collating order will sort to the end.
>                 
>                 For example (and this is an easy case) you can use
>                 this to specify a
>                 default collating order (based upon ordinal value of
>                 the code points
>                 themselves) for the 8-bit ASCII subset:
>                 
>                 ⎕ucs ⎕io-⍨⍳256
>                 
>                 
>                 
>                 On Tue, 2014-07-08 at 12:09 +0800, Elias Mårtenson
>                 wrote:
>                 > Dyadic grade doesn't make much sense in the context
>                 of Unicode though.
>                 > How do you grade an arbitrary Unicode string?
>                 >
>                 >
>                 > That issue is there even if we completely disregard
>                 all the
>                 > other Unicode-related collating issues.
>                 >
>                 >
>                 > Regards,
>                 > Elias
>                 >
>                 >
>                 > On 8 July 2014 12:00, David B. Lamkins
>                 <address@hidden> wrote:
>                 >         Check my follow-up post.
>                 >
>                 >         I'm fairly certain that the issue is whether
>                 monadic grade
>                 >         applied to a
>                 >         list of strings should do anything but
>                 signal a domain error.
>                 >         The ISO
>                 >         spec says that monadic grade is defined only
>                 on numeric
>                 >         arguments.
>                 >
>                 >         My test case appears to have monadic grade
>                 treating strings as
>                 >         if they
>                 >         encode numbers in a sufficiently large base.
>                 >
>                 >         If you want to sort strings, use dyadic
>                 grade. The left
>                 >         argument
>                 >         specifies a collating sequence.
>                 >
>                 >         On Tue, 2014-07-08 at 11:43 +0800, Elias
>                 Mårtenson wrote:
>                 >         > Ordering by size first makes very little
>                 sense to me. It
>                 >         makes it very
>                 >         > hard to sort any list of strings.
>                 >         >
>                 >         >
>                 >         > I was hoping that the following would have
>                 done so, but it
>                 >         also
>                 >         > suffers from the "length first" issue:
>                 >         >
>                 >         >
>                 >         >       z[⍋ ⎕UCS¨ z←'aa' 'xx' 'aaa' 'xxx']
>                 >         >  aa xx aaa xxx
>                 >         >
>                 >         >
>                 >         > What is the proper way to sort strings
>                 given the existing
>                 >         semantics of
>                 >         > grade?
>                 >         >
>                 >         >
>                 >         > Regards,
>                 >         > Elias
>                 >         >
>                 >         >
>                 >         > On 8 July 2014 02:34, David Lamkins
>                 <address@hidden>
>                 >         wrote:
>                 >         >         Looking at the spec, it seems that
>                 monadic grade is
>                 >         defined
>                 >         >         only for numeric data.
>                 >         >
>                 >         >
>                 >         >         That leaves open the question of
>                 whether my example
>                 >         should
>                 >         >         have signaled a domain error.
>                 >         >
>                 >         >
>                 >         >
>                 >         >         On Mon, Jul 7, 2014 at 11:25 AM,
>                 David Lamkins
>                 >         >         <address@hidden> wrote:
>                 >         >                 Given a list of character
>                 vectors (and
>                 >         scalars), grade
>                 >         >                 appears to generate the
>                 permutation vector
>                 >         first by
>                 >         >                 length then by content.
>                 >         >
>                 >         >                       ⍋'aaa' 'xx' 'y'
>                 'bbb' 'cc'
>                 >         >                 3 5 2 1 4
>                 >         >
>                 >         >
>                 >         >                 This seems
>                 counterintuitive. It seems as if
>                 >         ⍋ treats
>                 >         >                 character strings like
>                 numbers. Is this a
>                 >         bug?
>                 >         >
>                 >         >                 --
>                 >         >                 "The secret to creativity
>                 is knowing how to
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>                 >         >                 sources."
>                 >         >                    Albert Einstein
>                 >         >
>                 >         >
>                 >         >
>                 http://soundcloud.com/davidlamkins
>                 >         >
>                 http://reverbnation.com/lamkins
>                 >         >
>                 http://reverbnation.com/lcw
>                 >         >                 http://lamkins-guitar.com/
>                 >         >                 http://lamkins.net/
>                 >         >
>                 http://successful-lisp.com/
>                 >         >
>                 >         >
>                 >         >
>                 >         >         --
>                 >         >         "The secret to creativity is
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>                 >         your
>                 >         >         sources."
>                 >         >            Albert Einstein
>                 >         >
>                 >         >
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>                 >         >         http://reverbnation.com/lcw
>                 >         >         http://lamkins-guitar.com/
>                 >         >         http://lamkins.net/
>                 >         >         http://successful-lisp.com/
>                 >         >
>                 >         >
>                 >
>                 >
>                 >
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>                 >
>                 
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>                 
>         
>         
> 
>