Re: if-then-no-else Programming

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On 19/04/2016 04:24, Charles H. Sampson wrote:
> It's hard to believe that it's been over six years since I wrote a line
> of code for profit. If what my son tells me, there's been what I
> consider a major change in software engineering during that time.
>
> He says that there's a move to ban the use of the else-statement. The
> preferred approach is to execute the else-part first, then change the
> effect if the if-condition is satisfied. For example:
>
>     Variable := 3;
>     if <condtion> then
>        Variable := 1;
>     end if;
>
> In addition to some other goodness attributes, this is supposed to be
> clearer than the if-then-else form.
>
> Is he right? (He's not really a coder. His experience is in wire-frame
> animation but he's being forced into coding by the job market.) If he's
> not right, have any of you even heard of an area of the software
> "profession" where this position is held?

There are only few cases when asymmetric if-then is ever used.

1. Initialized default

    Variable : Integer := 3;
begin
    ...
    if <condition> then
       Variable := 1;
    end if;

Similar case is bulk initialization of arrays:

    Variable : String (1..80) := (others => ' ');
begin
    ...
    if <condition> then
       Variable (20) := 'a';
    end if;

2. Unbalanced terminating alternative. When THEN is very short and 
terminates some execution control path:

procedure Foo (Variable : out Integer) is
begin
    ...
    if <condition> then
       Variable := 1;
       return;
    end if;
    ... -- Do a lot of stuff
end Foo;

It could be "raise" instead of return, or "exit" when the variable is 
set as the result of a loop execution.

Otherwise, the advice is evident rubbish, as others have pointed out 
already.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de