[fpc-pascal] case statement

[Michael Van Canneyt]

On Thu, 14 Dec 2023, Adriaan van Os via fpc-pascal wrote:

>
> I am looking in detail at the syntax diagrams in the Freepascal Language 
> Reference (version 3.2.0)
>
> Section 13.2.2 discusses the case-statement. Translated to EBNF (WSN) the 
> syntax is
>
> case-statement = "CASE" expression "OF" case { ";" case } [ else-part ] [ ";" 
> ] .
> case = constant [ ".." constant ] { "," constant [ ".." constant ] } ":" 
> statement .
> else-part = [ "ELSE" | "OTHERWISE" ] statementlist .
>
> If this is correct (and the compiler really allows it) then a semicolon 
> between <case> and <else-part> is not required.

It is not required.

> Consequently, there is an 
> ambiguity between an if-then-else statement (as last statement of the <case>) 
> and an if-then statement (as last statement of the <case>) and an 
> <else-part>. This is extremely dangerous and I feel that at least the 
> Language Reference should warn against it.

A good point. I will add a warning.

>
> Even with an obliged semicolon, I always use "OTHERWISE instead of ELSE, but 
> that's my personal preference.

Indeed. By contrast I abhorr the OTHERWISE. Tastes differ.

Thanks for bringing the ambiguity to my attention.

Michael.