I don't think you're right about this. b has to be a verb to get results:
a =: 1 + b&+
b =: +
a 5
6
b =: 7
a 5
|domain error: b
| a 5
Henry Rich
Viktor Cerovski wrote:
>
> bill lam-2 wrote:
>> On Sat, 16 May 2009, Tracy Harms wrote:
>>> invocation, and verbs must be defined prior to execution.
>> IIRC undefined name are treated as verb. Suppose b is not yet defined,
>>
>> a=: 3 + b
>> a
>> 3 + b
>> b=: 1
>> a 10
>> |domain error: b
>> | a 10
>> b=: *:
>> a 10
>> 103
>>
> It's a bit more complicated. b is more like a free variable of universal
> type,
> which means it can become anything: noun, verb, adverb or conjunction.
>
> Such semantics is unusual (I can think only of Mathematica here),
> and the up side is that some things, like mutually recursive verbs, or
> parametric verbs, are easy to define, but the down side is that we
> don't know whether some expression with such a free variable will become
> well formed in the course of further interpretation or not, just as your
> example
> illustrates.
>
> Another apparently similar, but meaningless, expression is:
> c=:d+1
> |value error: d
> | c=: d+1
>
>
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
