I don't think Ian meant, or said, that amend-in-place violates any
rules. He said
[J] actually does in-place updating (even though, at face value,
J syntax does not permit such a thing).
The key words are "at face value". I take that to mean that a
beginner-to-advanced user, looking at the description of m}, would think
that it always produces a complete new array.
Ian's post makes it clear that he considering the inexpert J
programmer's view of J.
Henry Rich
On 9/9/2014 12:35 PM, Roger Hui wrote:
I don't believe the messages you cited explained it. J syntax consists of
word formation as defined by ;: and parsing rules as defined by Section IIE
of the dictionary. How is amend-in-place not permitted by either part?
On Tue, Sep 9, 2014 at 8:56 AM, Dan Bron <j...@bron.us> wrote:
Ian wrote:
Then it actually does in-place updating (even though,
at face value, J syntax does not permit such a thing).
Roger responded:
Please explain why this is not permitted by J syntax.
I believe Ian is expressing a thought recently raised by Erling Hellenas in
[1], which I responded to here:
http://www.jsoftware.com/pipermail/programming/2014-July/038030.html
-Dan
[1] "J and indexed replacement":
http://www.jsoftware.com/pipermail/programming/2014-July/038068.html
"In most languages indexed replacement is indexed replacement? In J
and
in most functional languages it is not? You get a brand new variable?
So, why give the user the flawed impression he can still do indexed
replacement and do amendments to variables/nouns? And at the same
time
in tacit code we pretend to only have functions? No variables/nouns
to
be amended? Just functional transformations?"
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