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.
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