As you know ObjectScript has neither FOREACH system command nor system function.
But it has a wide room for creativity.

The task is to loop over a global or local array and do something FOR EACH element.

There are 2 possible solutions:

• creating a macro that generates the required code sequences
• creating an Extended Command to perform the action. Both ways are presented here. The macro is a generic and quite flexible solution and easy to adapt if required.

##; ZFOREACHMACRO ; macro definitions
##; %key = variable provide to loop trough array
##; %arr = the gobal or local array to be looped on
##; %the method or routine to be executed for each node.
##; $$$foreach = forward loop $$$foreeachR = reverse loop
#define foreach(%key,%arr,%do) set %key="" for  set %key=$o(%arr(%key)) q:%key=""  do %do
#define foreachR(%key,%arr,%do) set %key="" for  set %key=$o(%arr(%key),-1) q:%key=""  do %do

You simply include the macro and apply it.
Example:

#include ZFOREACHMACRO   
test $$$foreach(key,^rcc,show)   
     quit
show zwrite @$zr,! quit   

Creating a command extension is available for all namespaces.

It needs to be included in %ZLANGC00.mac by #include ZZFOREACH
the related code is here:

##; run $order() ascending or descending on global or local arrays  
##; pass semicolon separated parameter string ("%array;%do;%fwd,;%key")  
##; %array = global or local variable name  
##; %do = routine or method to be executed for each run   
##; %fwd = 1/-1 loop direction ascending / descending, default = 1   
##; %key = first key if existing  
ZZFOREACH(%par) public {  
 set %par=$lfs(%par,";")
 new %array,%do,%fwd,%key,%val
 set %array=$lg(%par,1),%do=$lg(%par,2),%fwd=$lg(%par,3),%key=$lg(%par,4)
 if '%fwd set %fwd=1
 if %key]"" set %key=$o(@%array@(%key),$s(%fwd<1:-1,1:1))
 for  set %key=$o(@%array@(%key),%fwd,%val) quit:%key=""  do @%do
 quit 1 
}

In addition to the macro, the command allows optionally to run zzFOREACH
from a provided starting point forward or backward.
Examples:

DEMO>zzforeach "^rcc;show^dump(%array,%key,%val)"
^rcc(1) = 1
^rcc(2) = 2
^rcc(3) = 3
^rcc(4) = 4
^rcc(5) = 5

or from subscript 3:

DEMO>zzforeach "^rcc;show^dump(%array,%key,%val);;3"
^rcc(3) = 3
^rcc(4) = 4
^rcc(5) = 5

or the same reverse:

DEMO>zzforeach "^rcc;show^dump(%array,%key,%val);-1;3"
^rcc(3) = 3
^rcc(2) = 2
^rcc(1) = 1

GitHub

This is a demo to make use of a simple WebSocket Client with Embedded Python in IRIS.

How to Test it

• Run an Iris Session in Docker
• Select your WebSocket Echo Server
• Enter the text you want to send or generate it
• Send it and see the result

$ docker-compose exec iris iris session iris "##class(rccpy.WSockPy).Run()"

*** Welcome to WebSocket Embedded Python Demo ***

Collecting websocket-client
Using cached https://files.pythonhosted.org/packages/4c/5f/f61b420143ed1c8dc69f9eaec5ff1ac36109d52c80de49d66e0c36c3dfdf/websocket_client-0.57.0-py2.py3-none-any.whl
Collecting six (from websocket-client)
Using cached https://files.pythonhosted.org/packages/ee/ff/48bde5c0f013094d729fe4b0316ba2a24774b3ff1c52d924a8a4cb04078a/six-1.15.0-py2.py3-none-any.whl
Installing collected packages: six, websocket-client
Successfully installed six-1.15.0 websocket-client-0.57.0

%%%%%%

Known Hosts (*=Exit) [1]:
1 ws://echo.websocket.org/
2 --- server 2 ----
3 --- server 3 ----
select (1): 1 ==> ws://echo.websocket.org/
Python Connection Object:#
Enter text to get echoed from WebSocketClient Service
Terminate with * at first position
or get generated text by %
or append new text with @

1 hi this is python
2 from IRIS
3 *

Select action for WebSocket Service
Send+Listen(S),New Text(N),Exit(X) [S]S
%%%%%%%%%%%%%%%%%%%%%%%%%%

******* Submit 2 Lines *******
1 send> hi this is python
recv< hi this is python
2 send> from IRIS
recv< from IRIS

Select action for WebSocket Service
Send+Listen(S),New Text(N),Exit(X) [S]n
%%%%%%%%%%%%%%%%%%%%%%%%%%
Enter text to get echoed from WebSocketClient Service
Terminate with * at first position
or get generated text by %
or append new text with @

1 with some more text
2 %
2 * Lorem ipsum dolor sit amet, consectetuer adipiscing
3 * elit, sed diam nonummy nibh euismod tincidunt ut
. . . .
32 * un simplificat Angles, quam
33 * un skeptic Cambridge amico dit me que Occidental es.
34 *

Select action for WebSocket Service
Send+Listen(S),New Text(N),Exit(X) [S]s
%%%%%%%%%%%%%%%%%%%%%%%%%%

******* Submit 33 Lines *******
1 send> with some more text
recv< with some more text
2 send> Lorem ipsum dolor sit amet, consectetuer adipiscing
recv< Lorem ipsum dolor sit amet, consectetuer adipiscing
3 send> elit, sed diam nonummy nibh euismod tincidunt ut
recv< elit, sed diam nonummy nibh euismod tincidunt ut
. . . .
32 send> un simplificat Angles, quam
recv< un simplificat Angles, quam
33 send> un skeptic Cambridge amico dit me que Occidental es.
recv< un skeptic Cambridge amico dit me que Occidental es.

Select action for WebSocket Service
Send+Listen(S),New Text(N),Exit(X) [S]x
%%%%%%%%%%%%%%%%%%%%%%%%%%

$

Hints

%SYS.Python.html is a preliminary class docu to see available functions

run time: If the standard Python module is not yet installed this is the first action and happens only once.

GitHub