Re: IF..ELSEIF vs SELECT

On Sep 10, 2019, at 9:30 AM, Justin Taylor <JUSTIN@xxxxxxxxxxxxx> wrote:

Personally, I never use SELECT in RPG.


-----Original Message-----
From: john erps [mailto:jacobus.erps@xxxxxxxxx]
Sent: Tuesday, September 10, 2019 5:36 AM
To: rpg400-l@xxxxxxxxxxxxxxxxxx
Subject: IF..ELSEIF vs SELECT

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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