Re: else ladders practice

On 05/11/2024 16:03, Bart wrote:

On 05/11/2024 12:42, Waldek Hebisch wrote:

Bart <bc@freeuk.com> wrote:

>
Then we disagree on what 'multi-way' select might mean. I think it means
branching, even if notionally, on one-of-N possible code paths.

>
OK.

The whole construct may or may not return a value. If it does, then one
of the N paths must be a default path.

>
>
You need to cover all input values.  This is possible when there
is reasonably small number of possibilities.  For example, switch on
char variable which covers all possible values does not need default
path.  Default is needed only when number of possibilities is too
large to explicitely give all of them.  And some languages allow
ranges, so that you may be able to cover all values with small
number of ranges.
>

 What's easier to implement in a language: to have a conditional need for an 'else' branch, which is dependent on the compiler performing some arbitrarily complex levels of analysis on some arbitrarily complex set of expressions...
 ...or to just always require 'else', with a dummy value if necessary?

If this was a discussion on learning about compiler design for newbies, that might be a relevant point.  Otherwise, what is easier to implement in a language tool is completely irrelevant to what is good in a language.
A language should try to support things that are good for the /programmer/, not the compiler.  But it does have to limited by what is practically possible for a compiler.  A fair bit of the weaknesses of C as a language can be attributed to the limitations of compilers from its early days, and thereafter existing practice was hard to change.