I rather prefer the 'A '||B format because it makes it very clear that I'm
doing string concatenation. I use the same construct in other languages.
REXX
C = 'A '||B
Python and Java
C = "A " + B
Bash
C = "A "
C += B
Etc.
I don't know of any (normal) language where whitespace is important. I don't
care for the fact that two (almost identical) lines give different results:
B = 'B';
C = 'A ' B;
SAY 'C = "'||C||'"';
C = 'A '||B;
SAY 'C = "'||C||'"';
C = 'A ' || B;
SAY 'C = "'||C||'"';
Gives two blanks between A and B in the first case and just one in the second
two cases.
FWIW, the difference between SUBWORD and PARSE isn't nearly as large as you
would think.
On z/OS, PARSE VAR completed a little over 6% more interations (13 million vs
12.3 million)
PARSE VAR A . . X .
Ran 30.000000 seconds and completed 13041893 iterations.
X = SUBWORD( A, 3 )
Ran 30.000000 seconds and completed 12300937 iterations.
On Windows, PARSE VAR completed a little over 7% more interations (44 million
vs 41 million)
PARSE VAR A . . X .
Ran 30.000000 seconds and completed 44698913 iterations.
X = SUBWORD( A, 3 )
Ran 30.000000 seconds and completed 41597318 iterations.
Eric Rossman
-----Original Message-----
From: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> On Behalf Of
Paul Gilmartin
Sent: Tuesday, April 23, 2024 10:42 AM
To: IBM-MAIN@LISTSERV.UA.EDU
Subject: [EXTERNAL] Re: REXX vs other languages WAS: Rexx numeric digits and
scientific notation question
On Tue, 23 Apr 2024 14:07:05 +0000, Schmitt, Michael wrote:
>You lost me when you say that rather than embrace the conventions, standards,
>and features of the language I'm coding in (REXX), I should restrict it to the
>limitations of other languages.
>
Did I say that? I was trying to take a middle ground.
>The maxim is to assume that readers of your code are familiar with the
>language you're coding in, and would expect your code to follow those
>conventions. It would /defy/ their expectations to code otherwise.
>
Be sparse and elegant but not rococo. I prefer:
'A' B
to (the equivalent):
'A ' || B
The latter seems to cater to the expectations of PL/I or some other language.
But I confess to an obsession with performance. Function call/return is
costly, so I'll use:
PARSE VAR A . . X .
rather than (the sparser?):
X = SUBWORD( A, 3 )
>-----Original Message-----
>From: Paul Gilmartin
>Sent: Monday, April 22, 2024 8:56 PM
>To: IBM-MAIN@LISTSERV.UA.EDU
>
>On Tue, 23 Apr 2024 10:59:47 +1000, Andrew Rowley wrote:
>> ...
>>To me, it is much clearer to be explicit, including the concatenation, e.g.
>>"DELETE " || foo
>>seems much clearer about exactly what is happening/expected, which are
>>variables and which are (expected to be) constant etc.
>>
>That overkill is apt to confuse a POSIX shell partisan who would see
>the blank as part of the command name and expect a failure such as:
> 813 $ 'rm ' foo
> -bash: rm : command not found
> 814 $
>
>The maxim is assume your readers have a moderate, not advanced,
>knowledge of the language and make little concession to conventions of
>other languages. Don't:
> 'DELETE' || ' ' || value( 'foo' )
>
>My stumbling block learning Shell was excessive familiarity with CMS,
>where command strings built by Rexx are parsed again by SVC 202. I
>tried to build command strings with sh to pass to a nonexistent
>subsequent parser. I got better in a couple days.
--
gil
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