Re: IF..ELSEIF vs SELECT

I don't think SELECT is more efficient than IF...ELSEIF as it's just
another syntax. However, if it was, it would not be noticeable regarding
the advanced architecture of OS/400. I think the efficient impl of case in
e.g. C has more to do with creating a "jump table".

On Tue, Sep 10, 2019 at 3:19 PM Luis Rodriguez <luisro58@xxxxxxxxx> wrote:

In some of the programming languages I know CASE is a somewhat more
efficient instruction than IF/ELSEIF. I don't know if that would be the
case (not pun intended) with RPG. On a personal level I find it a more
elegant and cleaner construct

Regards,
Luis

Sent from my Moto G phone. Please excuse my brevity.

On Tue, Sep 10, 2019, 06:36 john erps <jacobus.erps@xxxxxxxxx> wrote:

Hi,

Could anybody shed some light on when to use IF..ELSEIF and SELECT.

Seems to me that the semantics of SELECT is exactly the same as

IF..ELSEIF.

SELECT just takes one line more (the SELECT).

In other languages such as Java or Javascript you have a CASE statement.
Maybe the idea is like this CASE statement. However a "normal" CASE
statement like this selects between different individiual values of a
variable. However, each WHEN statement in a SELECT is a full loagical
expression, hence just the same as IF..ELSEIF.

I use select when i need to condition using one variable. For example:
SELECT
WHEN X = 1
...
WHEN X = 2
...
ENDSL

However:
SELECT(X)
WHEN 1
...
WHEN 2
...
ENDSL

Would be a much better syntax, which resembles the CASE statement.

I suspect that initially it would be just like a CASE statement, but, IBM
being IBM, and camels and committees.... it ends up as another way of
writing IF...ELSEIF.

So better to shun it, and, for simplicities sake, always use IF..ELSEIF.

Or

is there a good reason to use SELECT? E.g. to communicate that it is

simply

a choice between values like CASE?
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