Re: [netrexx-pipelines] Migrate OS/2 pipelines to NetRexx Pipes

[Rony G. F. <Ron...@wu...>]

Hi Mike,

On 6/10/2022 10:47 AM, hp...@we... wrote:
... cut ...
> You advised to use BsfContextVariables() to set, get, or drop
> variables of the _current_ variable pool.
> Please define "current" ;)

It is the context of the Rexx code executing BsfContextVariables(). ;)

... cut ...

> In contrast to the varset stage, varload will filter by default
> comments and blank lines before doing something like
>
>>    loop forever
>>       line = Rexx peekto()  /* readto() would do in this case */
>>       parse line.upper sc +1 vn (sc) sv
>>       BSFContextVariables("Set", vn, sv)
>>       readto()
>>    end
>
> My question is, how does BSFContextVariables() "know" which pool
> to use? 

There is no choice available to use any other pool than the context one, i.e. the variable pool of 
the location where your program runs BsfContextVariables(). (You could have a routine which collects 
the pipe results and returns it and at the receiver side issue the BsfContextVariables() with that 
data.)


> From my point of view, there are several available in this
> context: one of the stage involving BSFContextVariables(), another
> one of ooRexx that started the NetRexx pipe, which itself could be
> a method of a method of... and so on, resulting in several pools
> within the same program/application. And does it make a difference
> if BSFContextVariables() is called in a stage which was involved
> by callpipe or addpipe?

Then BSFContextVariables() will effect the Rexx context there.

> Is that described or documented somewhere? TIA!

Yes, BSFContextVariables() uses the ooRexx native API named "rexxapi.pdf", section "1.17. Rexx 
Interface Methods Listing", APIs named: DropContextVariable(), GetContextVariable() and 
SetContextVariable().

Just noticed that the context are "routine" and "exit", but not "method".

---

Getting, setting and dropping variables without BsfContextVariable():

If you want to read the variables of the current context you could use the RexxContext object's 
variables method like this (cf. rexxref.pdf, section "5.4.16.12. variables"):

    do counter c with index idx item value over .context~variables
         say "#" c":" idx"="value
    end

If you want to set variables (instead of interpret) you can use the value() BIF (built-in function) 
like this:

    call value hi, 'hi, my beloved world'
    say hi /* will say 'hi, my beloved world'

If you want to drop variables use the DROP keyword statement like this:

    drop hi
    say hi /* will say 'HI' */

HTH,

---rony