Re: [Bug-apl] Identify function

[Juergen Sauermann]

Hi,

I have added monadic ⊣ and ⊢ see SVN 355.

Instead of making them identical I though it might be better to do
different things. What I came up with is this:

⊢ B returns (a copy of) B as a normal APL value.
⊣ B also returns a copy of B, but as a committed APL value.

Thus ⊣ can be used (instead of 0 0⍴) to supppress the display of a value:

      ⊢1 2 3
1 2 3

      ⊣ 1 2 3
(nothing)


/// Jürgen


On 07/01/2014 07:02 PM, David Lamkins wrote:

Further insights here:

http://aplwiki.com/Left,%20Right,%20or%20the%20Same%3F

BTW, note that ISO APL conjugate returns DOMAIN ERROR for a non-numeric argument. When Dyalog introduced the identity function, they deprecated use of + as identity; perhaps they're attempting to move closer to standards conformance in this case.

On Tue, Jul 1, 2014 at 9:56 AM, Elias Mårtenson <address@hidden> wrote:

Exactly, and since an identity function is useful it makes sense to map it to the same symbol as Dyalog.

Regards,

Elias

On 2 July 2014 00:55, David Lamkins <address@hidden> wrote:

Digging further, it's interesting to note that ISO APL defines + as conjugate, but does not have a binding for the identity function.

On Tue, Jul 1, 2014 at 9:42 AM, David Lamkins <address@hidden> wrote:

I looked this up yesterday. Dialog version 13 introduced the use of the tack as identity and repurposed + as conjugate. (Actually, they bound both left and right tacks identically, even though they call left tack "same" and right tack "identity".) If the argument of conjugate is imaginary, conjugate returns the number with the imaginary part negated. If the argument of conjugate is real or non-numeric, conjugate returns the argument unchanged.

From: Juergen Sauermann <address@hidden>

To: "Elias Mårtenson" <address@hidden>
Cc: "address@hidden" <address@hidden>
Date: Tue, 01 Jul 2014 17:04:24 +0200
Subject: Re: [Bug-apl] Identify function
Hi Elias,

I looked in "Mastering APL" from Dyalog and could not find it.
They call + the identity function.

And what would be the use of it?

/// Jürgen

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