Let me put this a different way. Solve the following puzzle in J.
Demonstrate the difference between:
I =: $0
and
B =: 0$0
The difference must be guarunteed (predicted, fully supported) by the
Dictionary, excluding the foreign conjunction !: and the Appendicies. To put
it another way, you may not leverage bugs in the implementation or J's
introspection.
Assume you're running under jconsole -jprofile: that is, you may not depend on
any sentence having been executed before your own. Put another way, do not
rely on the names normally defined by the J standard library.
For example, if I'd said find the difference between I and
L =: ''
you could easily demonstrate it thus:
I =&{. L
0
and support it by quoting Section II.B or the Vocabulary entry for {. :
2302 239 qdoj '{.' NB.
http://www.jsoftware.com/help/dictionary/dictb.htm
In an overtake (in which the number to be taken exceeds
the number of items), extra items consist of fills; zeros
if y is numeric, a: if it is boxed, spaces if literal, and
s: ' ' if symbol.
2725 163 qdoj 'dictb' NB.
http://www.jsoftware.com/help/dictionary/d521.htm
padding with an appropriate fill element: space for a
character array, 0 for a numeric array, and a boxed empty
list for a boxed array.
but the task will not be so trivial with I vs B . Remember that you may
not use !: .
-Dan
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