[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Bug-apl] scalar/array

From: Kacper Gutowski
Subject: Re: [Bug-apl] scalar/array
Date: Sat, 4 Mar 2017 17:39:49 +0100
User-agent: NeoMutt/20170113 (1.7.2)

On Fri, Mar 03, 2017 at 02:57:00PM -0700, address@hidden wrote:
> cause   1  is 1 element   and 1 2 3 is 3 elements   so   ⍴ 1 2 3   is 3    
> and  ⍴ 1  should have been 1

But 1-element arrays come in many different shapes and ⍴ returns the shape
rather than number of elements.  To get the later you would use ×/⍴ and ×/⍴1
is indeed 1 but so is ×/⍴(1 1 1 1⍴1).

As for the syntax, it's not exactly accurate and doesn't apply to character
vectors but I find it convenient to assume that bare number is always a scalar.
Consider that in APL2 you can create vectors by juxtaposing values:

      1 2 ≡ A B

So we can pretend there is no special syntax for numeric vector literals at
all.  It doesn't translate well to character vectors but I consider 'aa' to
be a syntactic sugar for 'a' 'a'.

I don't know the original reasoning behind it but I think it's the most natural
to have bare number literal stand for the most basic kind of value that exists
in a language.  As long as we want to have 0-rank arrays (and we do!), forcing
one to write something like ↑1 to get a scalar would be weird and I prefer
having to write ,1 for vector instead.


reply via email to

[Prev in Thread] Current Thread [Next in Thread]