funcB_B_ geomean_A_`'' ; data
do not use f. inside funcB. f. will lose locale info
From: 'Jon Hough' via Programming <[email protected]>
To: [email protected]
Sent: Friday, September 1, 2017 1:09 AM
Subject: Re: [Jprogramming] Passing class member gerund to verb in another
locale
I forgot to add a definition of funcB
cocurrent 'B'
funcB=: 3 : 0
'vrb data' =: y
f=: vrb `: 6 NB. vrb is the gerund
f data NB. call f. This creates the error.
)
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On Fri, 9/1/17, 'Jon Hough' via Programming <[email protected]> wrote:
Subject: [Jprogramming] Passing class member gerund to verb in another locale
To: "Programming Forum" <[email protected]>
Date: Friday, September 1, 2017, 2:03 PM
My problem is, I have a class 'A' say.
and I have a locale 'B'.
A contains several verbs. I would like
to pass a verb (or gerunds of the verbs), let's call it
myVerb, to some verb in B. However, this creates a problem,
as
when the B verb tries to call myVerb it
cannot find it, being in a different locale. i.e. I get a
value error. I attempted to use fix (f.) to get myVerb
explicitly, but this only
works if myVerb does not contain any
other verbs from A.
This is the contrived example, that is
essentially the same as my real problem, but stripped of
superfluous things:
NB. A is some class with several
verbs.
coclass 'A'
create=: 3 : 0
d=:y
)
NB. some verb in A
geoMean=: 3 : 0
(#%:(*/)) y
)
NB. I want to pass this to another verb
in another locale.
NB. Note that it calls geoMean.
myVerb =: 3 : 0
((geoMean f.) ; (+/%#)) y
)
NB. calling a verb in B
getAvg=: 3 : 0
data=.y
funcB_B_ ( myVerb f. `''); data
)
NB. create my instance of A
myA =: 0 conew 'A'
NB. call myVerb. No problem here!
myVerb__myA 1 2 3
NB. pass myVerb to funcB_B_
getAvg__myA 1 2 3
NB. this gives an error
|value error: geoMean
| ((geoMean
f.);(+/%#))y
Solutions:
(1) One solution is to make funcB_B_ a
conjunction / adverb. But in reality, I want to send several
verbs to funcB together.
(2) Another solution is to send the
instance reference of A to funcB (i.e. just send the whole
of myA to funcB). But I would prefer not to send the whole
object, as it then makes B less flexible, because I may want
to call funcB_B_ without the need for a class instance, just
a standalone verb.
(3) Another solution is to not call any
other verbs of myA inside myVerb__myA. This is not a
realistic solution as A could be quite complicated.
Is there a better way?
Just to explain my motivation, I am
trying to replicate the functionality most languages that
have first-class functions possess - to pass arbitrary
function(s) to
other functions and call them.
e.g. in Python
# myVerb is a Python function, and
could be a member method of some class. someData is just
some data
def funcB (myVerb, someData):
return myVerb(someData,
someOtherData)
Obviously J doesn't have first class
functions in this sense, but with gerunds, I was hoping to
be able to recreate the functionality.
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