Re: [netrexx-pipelines] Ad writing filters/stages in oo/rexx (Re: Ad ooRexx scopes, ... (Re: Migrate OS/2 pipelines to NetRexx Pipes

[<hp...@we...>]

Hi!

Am 12.06.2022 um 17:55 schrieb Rony G. Flatscher:
> Learned from René that it is possible to use external programs,
> also Rexx programs in NetRexx pipes like:
>
>     pipe literal curl http://example.com | command | cons
>
> So you can write oo/Rexx filter programs to be used as NetRexx
> pipe stages.

That is a very handy hint, thank you René and Rony for forwarding it.

> The oo/Rexx filter (reading from stdin, writing to stdout) would
> have to be written like:
>
>     do until line=""
>         parse pull line /* read from stdin */
>         ... do something with line and if you want to pass on data
> do ...
>         say editedData  /* writes to stdout */
>     end
>
> alternatively, one could write the Rexx filter also as (preferable):
>
>     signal on notready /* raised if stdin gets closed */
>     do forever
>         parse linein line
>         ... do something with line and if you want to pass on data
> do ...
>         say editedData  /* writes to stdout */
>     end
>     notready:          /* label to jump to */

That looks promising :)

> If you also want to write to stderr then you could either do that
> in classic Rexx style with "call lineout stderr,data" or in ooRexx
> ".error~say(data)".
>
> You may want to look through these slides:
> <https://wi.wu.ac.at/rgf/wu/lehre/slides/BusinessProgramming/060_ooRexx_commands_V14.pdf>.

Rony! I took the chance and browsed also through the other sets of
slides available there -- and besides 2..3 things about REXX I
learned two facts about i) Prof. Rony G. Flatscher that ii) he was
part of the team negotiating with IBM about ooRexx. So I get help
from the top-notch expert himself. Hope your students are less
demanding than I might be as mainframe dinosaur.

Best,
M.