On 12/05/2019 19:39, Ondrej Pokorny wrote:
On 12.05.2019 18:56, Jonas Maebe wrote:
As far as range checking and undefined behaviour is concerned, they
do. I.e., you won't get undefined behaviour by assigning any value
between low(enum)..high(enum) to them.
Very good, thank you. IMO this should be clearly documented to avoid
confusion.
True.
And if they are valid they should not cause any runtime errors:
program Project1;
{$mode objfpc}
type
TMyEnum = (two=2, five=5);
var
E: TMyEnum;
begin
E := TMyEnum(3);
Writeln(E); // RunError (107)
end.
(From the above example one would say they are not valid.)
write(enum) is an FPC extension. It writes out the declared enum
identifier. There is none in this case, so a run time error is appropriate.
There was a misunderstanding. I thought you meant with "implicit" values
the "implicit default values" (=0):
program Project1;
{$mode objfpc}
type
TMyEnum = (two=2, five=5);
TMyObject = class
E: TMyEnum;
end;
var
O: TMyObject;
begin
O := TMyObject.Create;
Writeln(Ord(O.E)); // R has an implicit default valuethat is invalid
ReadLn;
end.
But you meant the implicit valid values (the holes). Now it's clear.
Ah, indeed.
Jonas
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