Playing around with type bounds, I just discovered these things about ^ that I
don't recall seeing in the documentation:
9!:14 ''
j807/j64nonavx/linux/release/GPL3/voidlinux.org/2019-09-30T12:27:01
2&^ 1023 1024
8.98847e307 _
(3!:0)@^&>/~ 0;1;2
4 4 8
4 4 8
8 8 8
and from j-bot on the IRC channel:
9!:14 ''
j701/2011-01-10/11:25
(3!:0)@^&>/~ 0;1;2
1 1 8
1 1 8
4 4 8
So it seems that ^ is producing floats in general. I assume this is why 2^1024
is _ here, since IEEE floats have a maximum exponent of 1023 in their 64-bit
binary representation. Does this mean that on 32-bit machines _ = 2^128? I
suspect this is something to be aware of if developing cross-platform.
Futhermore, looking at the type tables above, what's going on in the top-left
corner? My naive interpretation is that ^ handles boolean arguments specially.
I am also curious about the origin of the j701 and j807 difference.
Stepping back a bit though, I also wonder if I am digging around in details
that are mostly ignorable (by design). For the most part everything seems to
Just Work TM, irrespective of the implicit type conversions, e.g.
|: (, 3!:0)&-.&> 0;1;(<"0) i.2
1 0 1 0
1 1 4 4
For which we might say that integer 0 and 1 agree with the boolean arguments
because probability complement agrees with boolean Not in these cases.
About the only suprise with types I've actually stumbled upon is with monadic
<. and how it handles tolerance differently for real vs. complex arguments,
which I posted about in a previous comment.
Does J's implicit type conversion have any other gotchas that one should be
aware of?
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