On 24/06/2021 8:51 pm, Seymour J Metz wrote:
The only meaning that I'm familiar with is the one that I get on a search for
'callback definition programming'. Or were you thinking of a non-computer
contest?
Callback is is a well known pattern
https://en.wikipedia.org/wiki/Callback_(computer_programming)
The ,array class goes all the way back to OREXX in OS/2. 5.0 adds a
regex class, but it doesn't support captures, and I rely on them heav
I must admit I don't really care
--
Shmuel (Seymour J.) Metz
http://mason.gmu.edu/~smetz3
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Subject: Re: Coding for the future
On 24/06/2021 9:23 am, Seymour J Metz wrote:
You invoke ISPF. You call a REXX script for ISPF. The script does ADDRESS
ISPEXEC foo and ISPF gets control back. It's well documented in the TSO/E REXX
Reference, and other implementations have essentially the same API. Basically,
when a REXX-aware application creates an environment, REXX associates context
with the environment name; when a REXX script routes a command to that
environment, the environment block contains the context so that the application
can locate its control blocks. It's quite elegant, and REXX does all of the
heavy lifting.
Yes, I'm familiar with the environment block as I have used IRXSUBCM to
create host command environments. In my case I had to use CEEPIPI to
create an LE environment for the C++ regex library. The environment
block has a user context pointer which is very useful. I was confused by
the term "call-back" which means something quite different to me.
On the flip side, prior to OREXX everything was a string; there was no type
checking, only value testing. Also, the exception handling is fragile compared
to PL/I, Python or Ruby.
I noticed that ooRexx v5 has introduced array types which is long
overdue. Stem variables are hash tables so performance is not great when
iterating.
--
Shmuel (Seymour J.) Metz
http://mason.gmu.edu/~smetz3
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From: IBM Mainframe Discussion List [IBM-MAIN@LISTSERV.UA.EDU] on behalf of
David Crayford [dcrayf...@gmail.com]
Sent: Wednesday, June 23, 2021 8:57 PM
To: IBM-MAIN@LISTSERV.UA.EDU
Subject: Re: Coding for the future
Maybe I'm missing a subtlety here but can you demonstrate how REXX uses
callbacks on z/OS? I'm familar with command environments, I've written
one for REXX regex
https://secure-web.cisco.com/140q8fxdqURUGvmth2nK_lOrDPN09AtW0cBfgGnzMZm6MOvOho-HriWxdOrBSwiPotV2P6kacF9rpRwTORQsYeHqbOlnMFxHuUDYsjYnWlk0z0sR7CYhLEzIyd-DL6yuI6IRotLmLhmT3RbCQk9-VO0E6-NE3tyAdm1jgxYV9K6GosVOwG_tqv0j_Iv7TeRrCoUvhQ5ZNmnH2N9gR8CjU9xFydEZWlX1Y702G19rTTW9fV0qRkhU5kTGg16f16KMPIZbaB7Cqk0evdWJylMOkSMkIA5PECEmFeyiQXvrOBE2LDvGMC16AK6OZg5xdnzeWpSgm_g5F-nCgOQjteQ_82RUkquwXW_WqLZq0S0yXoz4PpyFEFJrpl2iZboK4FhuXZdrvui3BqiSrz0nKNJYIXUNRpVzfCH02p2xcc1Oqa0Lrndw3QSeal5ZFf3sRqGP-/https%3A%2F%2Fgithub.com%2Fdaveyc%2FRTK.
In Python, Lua etc you
would just create an instance of a class an communicate using message
passing like any OO language.
For example, to create and ISPF in Lua you instantiate and ISPF object
and then communicate with it by calling methods
https://secure-web.cisco.com/1qsEFCKQQ8_UfI8nvAPUHIHUMRsk8zVcv8tyCsWKzPB5x6Iqcinh6eFRTvMYUE_fu4U_RlstYoTVGhhME8x92IIYlUFy0AvsQ_osnJyM5U0ASEu77n43wTA2l6-3XA99vaRmgsICvmmQW_Wlc1RO5W5SsL6uXFqvGMNSV5d2Swy6V131ckAPNDw9a-BsfYVkO5DRvOINNh9iJZqVw466fpXNjZh1CsFmaMQcpIvnXTnndqgbQwZw4yzPuxvmWTf__4ssShTUeQnjYxO6gcW4YsvpHhQslzGOP7V45e2SIHjYK3A2EGLp3hyelRfJG9gh3h0qFBX_1a5X08xba0wB0HwMXf4VyHIzAvI5LKoqvrMA90FsZq4h6TMxefXsiXKHALdxZV9djrJXqln73WhSCoaNFiVgG9C-wOFEwYW7bB12UrfhpL6v1ZJ3Hxudjq_4kHxQJuH7g6y4Brb90haU3vA/https%3A%2F%2Flua4z.github.io%2FLua4z%2Fmodules%2Fispf.html.
On 23/06/2021 7:04 pm, Seymour J Metz wrote:
Allow applications to establish environments for scripts (ADDRESS) , allow
call-backs from within scripts and access the variables of the scripts. I wish
that I could do that from within Perl, although I'd take the time to learn
Python or Ruby if they supported that.
--
Shmuel (Seymour J.) Metz
http://mason.gmu.edu/~smetz3
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From: IBM Mainframe Discussion List [IBM-MAIN@LISTSERV.UA.EDU] on behalf of
David Crayford [dcrayf...@gmail.com]
Sent: Wednesday, June 23, 2021 3:19 AM
To: IBM-MAIN@LISTSERV.UA.EDU
Subject: Re: Coding for the future
On 23/06/2021 10:38 am, Seymour J Metz wrote:
None of those are relevant to what REXX does best. Again, it's the plumbing,
not the syntactic sugar.
What exactly does REXX do best? What does it do better than Python?
As to large applications, I believe that there are some pretty big ones in Perl
and REXX, so why should I be surprised by large applications in, e.g., Python,
Ruby?
--
Shmuel (Seymour J.) Metz
http://mason.gmu.edu/~smetz3
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From: IBM Mainframe Discussion List [IBM-MAIN@LISTSERV.UA.EDU] on behalf of
David Crayford [dcrayf...@gmail.com]
Sent: Tuesday, June 22, 2021 7:25 PM
To: IBM-MAIN@LISTSERV.UA.EDU
Subject: Re: Coding for the future
On 22/06/2021 10:19 pm, Seymour J Metz wrote:
It's not a question of what environment it can run in; it's a question of what
facilities it supports in those environments.
Indeed. Lua supports TSO, ISPF, CICS, IMS, the full MVS file system
including VSAM. DB2 SQL + a SQLite API. A date/time module that supports
dates that are greater than Mon Jan 01 1000000 BCE 00:00:00 and less
than Mon Jan 01 1000001 00:00:00 etc, etc.
We presented at SHARE where we demonstrated how to use Lua integration
to convert a 3270 CICS BMS application to a mobile web app
https://secure-web.cisco.com/1LTRemd3KBmC5tUUKSeo9EC5h9xyRF7Bz3PhdCSMXFnXeU9xUYZAMVe5chb0ZaeK3DMtRGm6fXidrWX-DdewRuiBFuunmJgylrBSK2m0dxTkBwteMqPfIErfpIkx2t0yKE_X4Vvjo2z5bwL3x5Gzol57ueWGXt0mRa5LkbagnGSXpBSeh0a0sqCHTv7dZ_yP7bvWRZEdnEhIKqF6yOijhnDFn7l75N3TqnoUwxHNnsOFWy_ZGihMqSRgOpFgNGT29c3jEMR9BWE6SwalS5Fq9qCm5mI3QT3QGXbhUjO6A4bL_zu9qSlFAFZM7PJeBTr73ngdhubfDFqh0fRWaFg5cyBhzcMGUTVbEV5QWTr76UNB_zRihnfVeyioclr2jou2HVmP2A7PlvHHZDFG0y1o-fR5mEjE0DxE6Jrzclf2Oy-W2TISt9m1rarhndnanZuca/https%3A%2F%2Fshare.confex.com%2Fshare%2F123%2Fwebprogram%2FHandout%2FSession15892%2F15892%2520Mobile%2520CICS%2520Application%2520Using%2520Lua.pdf.
I spent a lot of time making sure Lua integrated well into the TSO/MVS
environment. The irony is I spend very little time in TSO/ISPF these
days. I spend most of my time in a shell and switch the ISPF when I want
to use SDSF. I write new scripting code in Python which is enhanced
ASCII so only
runs in z/OS UNIX. Rocket and IBM don't see any value in integrating
ported tools with TSO as it's not strategic. The main focus is on
containers.
BTW, did you know that the photo sharing app Instagram is written in
Python? It's staggering to imagine that what we would consider a
scripting language is serving over 1 billion monthly users.
--
Shmuel (Seymour J.) Metz
http://mason.gmu.edu/~smetz3
________________________________________
From: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> on behalf of David
Crayford <dcrayf...@gmail.com>
Sent: Tuesday, June 22, 2021 9:57 AM
To: IBM-MAIN@LISTSERV.UA.EDU
Subject: Re: Coding for the future
On 22/06/2021 8:55 pm, Seymour J Metz wrote:
What distinguishes REXX is not syntactic sugar but the plumbing that enables
close coupling of scripts with applications. Lua is missing that.
Maybe. But I can't think of an environment that REXX runs in that Lua
can't. I could port Python to run in TSO if I had the time but it's a
heavy lift. IBM have ported golang now which is compiled. We've had a
look at it and it's interesting.
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