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## Re: [Bug-apl] A question.

 From: Elias Mårtenson Subject: Re: [Bug-apl] A question. Date: Wed, 18 May 2016 10:56:21 +0800

I'll give it a shot:

foo ← {⍺ ⍶ ⍵}

This defines foo as an operator that applies the function on its two arguments.

I.e. in the following example:

10 +foo 20
30

The foo operator simply applies + to 10 and 20, returning 30. In other words, ⍶ is the function that goes to the left of the operator name.

Similarly, ⍹ is the function that goes on the right of the operator name:

bar ← {(⍺ ⍶ 2) ⍹ (⍵  3) }
10 +bar- 20
¯11

The call to bar results in the following formula being evaluated: (10+2)-(20+3).

Regards,
Elias

On 18 May 2016 at 10:48, Christian Robert wrote:
Sorry, no explanations given.

hook←{⍵⍶⍹⍵}
+hook÷2
2.5
hook←{⍵⍶⍹⍵⊣⎕←⍵⊣⎕←⍶⊣⎕←⍹⊣⎕←⍵}
+hook÷2
2
DOMAIN ERROR
hook[1]  λ←⍵ ⍶ ⍹ ⍵⊣⎕←⍵⊣⎕←⍶⊣⎕←⍹⊣⎕←⍵
^^
please explain the principle to a newbie.

I really want a working examples.

Xtian.

On 2016-05-17 22:30, Xiao-Yong Jin wrote:
They are for direct function (operator?) definitions.  Try:

hook←{⍵⍶⍹⍵}
+hook÷2
2.5

On May 17, 2016, at 8:24 PM, Christian Robert <address@hidden> wrote:

hi,

in the result of "]help" I can see:

λ       { ... } result
⍺       { ... } left value argument
⍵       { ... } right value argument
χ       { ... } axis argument
⍶       { ... } left function argument
⍹       { ... } right function argument

can someone explain to me the usage of ⍶ and ⍹
with some examples ?

I understant the first four, but not the last two.

many thanks,

Xtian.