Hokey (The Moderator) <hokey@plus5.uucp> (03/10/85)
std-mumps Digest Sat, 9 Feb 85 Volume 1 : Issue 10
Today's Topics:
Exotic Language of the Month Club
fun with setpieces (2 msgs)
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Date: 9 Mar 85 01:38:21 CST (Sat)
From: hokey@plus5.uucp
Subject: Exotic Language of the Month Club
To: std-mumps
Mumps was selected as the "Exotic Language of the Month Club" feature in
the Feb. '85 issue of "Computer Language".
The article was written by J. Edward Volkstorf Jr.
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Date: Thu, 7 Mar 85 17:19:40 est
From: ihnp4!watmath!wateng!jmmussi (Jose Mauro F. Mussi)
Subject: fun with setpieces
To: jmmussi, watmath!ihnp4!wucs!plus5!hokey
From: hokey@plus5.uucp (Hokey)
> According to the Standard, the behavior is:
>
> $P(glvn,d,m,n)=expr
>
> 1) scan the glvn and evaluate subscripts. (doesn't affect naked)
^^^^^^^
even if the subscripts are naked references?
> 2) evaluate d, m, n (can affect naked)
> 3) evaluate the expr to the right of the = (can affect naked)
> 4) bounds check m and n
> 5) evaluate glvn ("resolve" naked glvn)
>
In my opinion, the use of naked references should be very restricted.
This construction was created to improve file access performance by
reducing the number of hierarchical levels of a global variable that
must be search to find a specific node. However, this improvement was
only possible due to the nature of the internal file structure in
earlier mumps systems. I imagine that all current implementations must
use other tree structures (B* or AVL) for files where all subscripts
are needed to produce the access key. In this case, naked references
have only been kept around to provide backward compatibility. They do
not improve performance and in most cases there is actually a loss of
performance due to the concatenation of the subscripts in the naked
reference with the subscripts of the last global variable reference
(except the last subscript of course).
I would like to receive comments on the correctness of the statements
above and also would like to know the opinion of other mumps programmers
about the "convenience" of using naked references.
Jose Mauro Fialho Mussi
Dept. of Electrical Engineering
University of Waterloo
Waterloo, Ont., N2L 3G1
Canada
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Date: 9 Mar 85 01:33:39 CST (Sat)
From: hokey@plus5.uucp
Subject: fun with setpieces
To: std-mumps
Jose, you caught me. I was not explicit enough. If the glvn is a gvn,
it does not affect the naked indicator when it is initially scanned. Any
nakeds or globals present as subscripts within the glvn *do* affect the
naked indicator. I shouldn't have been so brief.
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End of std-mumps Digest
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Hokey ..ihnp4!plus5!hokey
314-725-9492