The REXX term of art "environment" makes that ambiguous. REXX could run 
initially on CMS and later on GCS. On CMS it supported the environments CMS, CP 
and XEDIT.

No, there is no problem with a keyword being the same as the name of an 
environment, other than making the program harder to read. The statement 
"ADDRESS SAY" would be perfectly unambiguous should someone be perverse enough 
to use SAY as the name of an environment.. 


-- 
Shmuel (Seymour J.) Metz
http://mason.gmu.edu/~smetz3
עַם יִשְׂרָאֵל חַי
נֵ֣צַח יִשְׂרָאֵ֔ל לֹ֥א יְשַׁקֵּ֖ר




________________________________________
From: IBM Mainframe Discussion List <[email protected]> on behalf of Jon 
Perryman <[email protected]>
Sent: Saturday, June 21, 2025 1:42 PM
To: [email protected] <[email protected]>
Subject: Re: REXX say


External Message: Use Caution


On Fri, 20 Jun 2025 18:32:59 -0500, Glenn Knickerbocker <[email protected]> 
wrote:

>Mike's explanation in The REXX Language was that "SAY . . . typically causes 
>it to be displayed (or spoken, or typed, etc.) to the user."  He had blind 
>friends (and/or antagonists) using talking terminals among the early users, so 
>for them SAY really did mean "say."

This makes for an entertaining story, but I suspect SAY was an actual design 
decision. Mike designed REXX for VM to support multiple future environments 
(first 2 were CP & CMS). REXX instruction names (e.g. SAY, PULL and more) must 
avoid conflicts with all future environments. Clearly, he knew about the CP msg 
and message commands where "msg abc" can't be both REXX and CP. SAY and PULL 
are unlikely to conflict with any environment.

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