It's a GNU APL extension. Standard APL does not support functions with
indexes. Since GNU APL does, it also needed a symbol to represent that
parameter inside lambdas.
Regards,
Elias
On 1 August 2014 10:49, Peter Teeson <peter.tee...@icloud.com> wrote:
> Thanks Elias:
>
> David used theta as well. Is that also an available symbol?
> i.e. a greek letter not otherwise used by the APL language?
>
> I will have to Google for a good intro to lambdas…
> They look interesting...
>
> respect…
>
> Peter
>
> On 2014-07-31, at 10:11 PM, Elias Mårtenson <loke...@gmail.com> wrote:
>
> Yes, you are right. Here are the available symbols:
>
> ⍵ - Right-hand argument
> ⍺ - Left-hand argument
> ⍹ - Right-hand function (the lambda is an operator)
> ⍶ - Left-hand function (the lambda is an operator)
> χ - Index
>
> Regards,
> Elias
>
>
> On 1 August 2014 10:04, Peter Teeson <peter.tee...@icloud.com> wrote:
>
>> Thank you kind gentlemen for helping me move forward with modern APL.
>> Am I correct in assuming that expressions such as {⍬≡0⍴⍵} are lambdas?
>> And that the symbols theta and omega are place holders similar to X and Y
>> in a user defined function?
>> (all new stuff to me BTW - but very interesting.)
>>
>> respect
>>
>> Peter
>>
>> On 2014-07-31, at 9:51 PM, Elias Mårtenson <loke...@gmail.com> wrote:
>>
>> This is the table I have included in the Emacs mode documentation. I got
>> the information from the ISO spec, so I hope it's correct:
>>
>> 0 (1-R⋆2)⋆0.5
>> ¯1 arcsin R 1 sin R
>> ¯2 arccos R 2 cosin R
>> ¯3 arctan R 3 tan R
>> ¯4 (R+1)×((R-1)÷R+1)⋆0.5 4 (1+R⋆2)⋆0.5
>> ¯5 arcsinh R 5 sinh R
>> ¯6 arccosh R 6 cosh R
>> ¯7 arctanh R 7 tanh R
>> ¯8 -(¯1-R×2)⋆0.5 8 (¯1-R⋆2)⋆0.5
>> ¯9 R 9 Real part of R
>> ¯10 +R 10 |R
>> ¯11 0J1×R 11 Imaginary part of R
>> ¯12 ⋆0J1×R 12 Arc R
>>
>> Regards,
>> Elias
>>
>>
>> On 1 August 2014 06:46, David B. Lamkins <dlamk...@gmail.com> wrote:
>>
>>> Reshape your datum as an empty vector then match to zilde. If the match
>>> succeeds then your datum is a number; otherwise a character/string.
>>>
>>> I believe that there's a circle function to extract the imaginary part
>>> of a number, if any. You can test for a nonzero imaginary part.
>>>
>>> Finally, you can compare a number's floor to the number itself to
>>> determine whether the value is integer or real.
>>>
>>> Not knowing your application, I have to warn you that you shouldn't use
>>> these tests to infer anything about APL's storage. All of the numeric
>>> tests are subject to quad-CT.
>>>
>>> On Thu, 2014-07-31 at 15:54 -0400, Peter Teeson wrote:
>>> > I feel pretty stupid.
>>> > Looked in the APL2 IBM manual but do not understand how to determine
>>> the data type of a variable.
>>> > Neither the primitives nor the Quads sparked the answer in my brain.
>>> > It must be something pretty obvious but not to me right now.
>>> >
>>> > So if I have a function FOO X how do I determine if X is character,
>>> integer, float, or imaginary?
>>> > Assuming that it is not a nested array of course.
>>> >
>>> > respect…
>>> >
>>> > Peter
>>> >
>>>
>>>
>>>
>>>
>>
>>
>
>
