foo=: (3 4$i.12)+/ .**:
   5!:6 <'foo'
(i.3 4) ((+/) .*) *:

Try: baa=. (+/)
or: baa=. ((+/) .*)
or: baa=. (i.3 4)  --Counterexample to conjecture 1: it's not a verb.


On Fri, Jul 20, 2012 at 5:22 AM, bill lam <[email protected]> wrote:
> I cannot understand your questions, could you give a simple and
> concrete example?
>
> Птн, 20 Июл 2012, Ian Clark писал(а):
>> For all my exposure to J, I can't answer the following simple(?)
>> questions. Can someone help please?
>>
>> Take the fully parenthesized representation of a given tacit verb: foo
>> (viz 5!:6 <'foo')
>> --note: "verb", not "sentence" (which might be a noun).
>> Take what's inside any pair of balanced parens: (...). Give it a name:
>> baa, so we can formally replace (...) with (baa) .
>>
>> 1. Is baa always a verb?
>>      Answer: no, because I can make phrases like: (-~) appear.
>>     BUT are there only a small number of special cases I can detect
>> and allow for, like (-~)?
>>
>> 2. If baa is not a verb, how can I determine its type?
>>     -short of actually assigning it to a local name: baa=. (...) and
>> calling 4!:0<'baa' ?
>>
>> 3. Is there an easy way to tell if baa gets called monadically or
>> dyadically, and if it gets the y-argument of foo -- and the x-arg too?
>>     Ignore the case of baa getting an intermediate noun -- I can
>> determine this from the paren nesting structure.
>>     Ditto a constant.
>>     Note I'm only concerned with the output of 5!:6, not what's
>> syntactically possible when a tacit verb can be entered by hand, where
>> a phrase in parens can of course be a noun.
>>
>>
>> I guess the answers can in principle be found from a very careful
>> reading of Help > Dic > E. Parsing and execution, and F. Trains. But I
>> must confess this is beyond me. Has the matter been summed-up
>> elsewhere more clearly?
>>
>> (And -- no, I haven't forgotten tte.ijs.)
>>
>> Ian
>> ----------------------------------------------------------------------
>> For information about J forums see http://www.jsoftware.com/forums.htm
>
> --
> regards,
> ====================================================
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> gpg --keyserver subkeys.pgp.net --recv-keys 4434BAB3
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm
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