Support plisql multi-range in conditional control

[TsinghuaLucky912]

The in condition in the for loop in Oracle's PL/SQL procedure language is list is supported:

ivorysql=# do $$
ivorysql$# declare
ivorysql$#    j int := 10;
ivorysql$# begin
ivorysql$#    for i in 1..3, reverse j+10..j+1 loop
ivorysql$#       raise info '%', i;
ivorysql$#    end loop;
ivorysql$# end; $$ language plisql;
INFO:  1
INFO:  2
INFO:  3
INFO:  20
INFO:  19
INFO:  18
INFO:  17
INFO:  16
INFO:  15
INFO:  14
INFO:  13
INFO:  12
INFO:  11
DO
ivorysql=#

[grantzhou]

Thank you @TsinghuaLucky912 for this great attempt! We are having the team review your patch.
Before we go through this, could you please create an issue regarding your PR? The future release notes need to include this feature explanation by referring to this issue.

[TsinghuaLucky912]

@grantzhou thank you for your reply

Previous FOR (Integer Variant):

[ <<label>> ]
FOR name IN [ REVERSE ] expression .. expression [ BY expression ] LOOP
    statements
END LOOP [ label ];

Now FOR (Integer Variant):

[ <<label>> ]
FOR name IN condition_iterator [ , condition_iterator ... ] LOOP
    statements
END LOOP [ label ];

condition_iterator:
[ REVERSE ] expression .. expression [ BY expression ]

[grantzhou]

Ok, I created one issue Issue 189 for you.

@grantzhou thank you for your reply

Previous FOR (Integer Variant):

[ <<label>> ]
FOR name IN [ REVERSE ] expression .. expression [ BY expression ] LOOP
    statements
END LOOP [ label ];

Now FOR (Integer Variant):

[ <<label>> ]
FOR name IN condition_iterator [ , condition_iterator ... ] LOOP
    statements
END LOOP [ label ];

condition_iterator:
[ REVERSE ] expression .. expression [ BY expression ]

[TsinghuaLucky912]

@grantzhou thank you very much