conjunctions take 2 operands, adverbs only one. If you need to pass in
two pieces of data, you can either box them as the left operand of an
adverb or pass them in as the two operands of a conjunction. It's
similar to the difference between monadic and dyadic verbs.
In a conjunction, the interpreter sets n to the value of the right
operand before the modifier starts running, but only if the right
operand is a noun. This gives you a way to have the modifier fail if it
needs a noun and is given something else.
Henry Rich
Yuvaraj Athur Raghuvir wrote:
> Hello,
>
> To add and remove verbs dynamically to a class from an instance, I wrote the
> following:
>
> addv =: (0!:0) inlocale
> remv =: (erase@<) inlocale
>
> I designed inlocale based on the JfC code for InLocales Conjunction [1]
>
> inlocale =: 2 : 0
> l =. gcurrent ''
> class =. {. @ copath n
> cocurrent class
> u y
> cocurrent l
> ''
> )
>
> This works in my tests.
>
> cocurrent 'base'
>
>
> 1. test01 =: 3 : 0
> 2. c =. conew 'myclass' NB. use copathnl__c '' to inspect
> 3. try. hello__c ''
> 4. catch.
> 5. vs =. 'hello =: 3 : 0',CRLF,'smoutput ''hello''',CRLF,')'
> 6. c addv vs
> 7. hello__c ''
> 8. end.
> 9. smoutput copathnl__c ''
> 10. c remv 'hello'
> 11. smoutput copathnl__c ''
> 12. destroy__c ''
> 13. )
>
>
> However, I do not understand two points:
>
> 1) When to design inlocale as an adverb (1 : 0) and when as a conjunction(2
> : 0)?
> 2) How does inlocale get the 'n' it wants in the execution of the statement
> number 6 & 10 in the test code?
>
> If this is already written down somewhere, please do point me to the
> reference.
>
> Thanks,
> Yuva
>
>
> [1]
> http://www.jsoftware.com/help/jforc/writing_your_own_modifiers.htm#_Toc191734500
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm
>
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
