[Jprogramming] NaN, p., and control structures

[Louis de Forcrand]

On the Indeterminate vocabulary page of the dictionary it is written

The only ways to create _. are as follows:
        direct entry of _. 
        ".
        3!:n
        DLL call (database, LAPACK, etc.)

and

Primitives on arguments not containing _. signal NaN error instead of producing 
_. .

yet (in j64-805 on macOS 10.10.5)

   2 7 p.1e308j_
_.j_

This is very dangerous, as comparison with _. seems to yield _. and it also 
seems that control structures treat _. as false instead of signalling an error 
(which is in my opinion a very bad idea).
Are both these behaviours intended?

Thanks,
Louis

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