On Wednesday, 21 October 2020 at 22:50:27 UTC, matheus wrote:
Since (1.1).to!int = 1, shouldn't the string value
("1.1").to!int at least try to convert to float/double and then
to int?
The thing is, that's a great way for hard-to-identify bugs to
creep into code. In these cases:
auto a = (1).to!int; // this works
auto b = ("1").to!int; // this works
auto c = (1.1).to!int; // this works and c = 1
... then what the programmer wants is unambiguous. In the first
case it's just converting int => int. In the second, it's
converting from a string that unambiguously represents an integer
value, to an int. And in the third, it's converting _at
programmer request_ from a double to an int (which has a
well-defined behaviour).
However, if ("1.1").to!int were to work, this would be the `to`
function making a judgement call on how to handle something
ambiguous. And while that judgement call may be acceptable for
your current use-case, it won't be for others.
In particular, if `to` just accepted any string numerical
representation for conversion to int, how could the caller
explicitly _exclude_ non-integer input, if that is their use-case?
So it's far better to require you, as the programmer, to make
what you want unambiguous and explicitly write code that will (i)
deserialize any numerical string that is acceptable to you and
(ii) convert to integer.
