Re: set temporary environment variables for builtins

[Bart Schaefer <schaefer@xxxxxxxxxxxxxxxx>]

On Sat, Dec 16, 2023 at 11:48 AM Clinton Bunch <cdb_zsh@xxxxxxxxxxx> wrote:
>
> Still wondering why the standard syntax for setting a temporary
> environment variable doesn't work for builtins.
>
> I don't think I'm unusual in expecting this to work:

https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_09_01
(2.9.1 Simple Commands)

"If the command name is not a special built-in utility or function,
the variable assignments shall be exported for the execution
environment of the command and
  (my emphasis) shall not affect the current execution environment
except as a side-effect of the expansions performed in step 4"

"print" is not a "special" built-in, so "shall not affect" applies.  "Step 4" is

"Each variable assignment shall be expanded for tilde expansion,
parameter expansion, command substitution, arithmetic expansion, and
quote removal prior to assigning the value."