On 12/05/2019 17:14, Ondrej Pokorny wrote:
On 12.05.2019 16:36, Jonas Maebe wrote:
Thanks. I have added these warnings to the compiler in r42047, and
also the static/dynamic errors for Standard resp. Extended ISO Pascal.
Very nice.
One question about "C-style enumeration types"
https://www.freepascal.org/docs-html/ref/refse12.html#QQ2-26-31
Do the holes between undefined enum values belong to the enumeration or
not? Because:
1.) The FPC documentation states they do not. See
https://www.freepascal.org/docs-html/ref/refse12.html#QQ2-26-31
/"The Pred and Succ functions cannot be used on this kind of enumeration
types. Trying to do this anyhow will result in a compiler error."/
It's because Pred and Succ do not make sense with enumerations with
holes in our opinion, and could be confusing. E.g. in your example, one
could expect at first sight that succ(one) = two.
2.) The Delphi documentation states they do. See
http://docwiki.embarcadero.com/RADStudio/Rio/en/Simple_Types_(Delphi)#Enumerated_Types_with_Explicitly_Assigned_Ordinality
/"An enumerated type is, in effect, a subrange whose lowest and highest
values correspond to the lowest and highest ordinalities of the
constants in the declaration."/
3.) Your newly added warnings indicate they do.
I simply forgot to take them into account. I'm tempted to disable the
warning altogether for them, because
1) Semantically, it would make sense to give a warning only if not all
explicitly defined enum values are covered
2) However, you still can't give an "unreachable code" warning if
there's an "else" in that case, because implicit values can also be
stored in the enum
That would make the warnings inconsistent.
Jonas
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