Re: implicit conversion
Seungbeom Kim wrote:
Martin Bonner wrote:
On Jun 25, 8:58 am, "gast...@hotmail.com" <gast...@hotmail.com>
wrote:
Actually, I would consider a boolean here to be an abuse, as it
fails to document the intention at the point of call. An
enumeration with values Unique and Empty is a much better
option, and clearly new values could be relatively painlessly
added as the interface evolves....
I think it is overkill: this kind of reasoning leads to question
every use of bool.
Why is that a bad thing? I would argue that most uses of bool as
the argument to a function are a mistake, and should be replaced
by a more specific enumeration.
The appropriate use of bool is as the return type of a function
like is_lower, or operator==().
Do you mean bool is good only for return types, not for parameter
types?
Mostly, yes.
bool is_empty(...); // good
void construct(bool is_empty); // bad
MyClass::MyClass(bool is_empty); // bad
Then, do you mean we have to convert the bool to an enum along the
information flow, like the following?
enum empty_t { not_empty, empty };
void construct(empty_t);
MyClass::MyClass(empty_t);
construct(is_empty(...) ? empty : not_empty);
if (is_empty())
construct_empty();
else
construct_full();
MyClass x(is_empty(...) ? empty : not_empty);
The problem here is the meaning of
MyClass y("Hello World!");
which also produces an "empty" object.
Bo Persson
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