On Monday, December 8, 2014 6:16:25 PM UTC+10, David van Leeuwen wrote:
>
> Good question, I would be interested in the answer myself. If the tips
> indicate the explicit type dependency is preferred, then I guess that for
> the first form the compiler compiles a new instance of the function
> specifically for the concrete type `T`, while in the second, it presumably
> compiles to deal with a (partly) type-instable `x` within the function
> body.
>
> f1{R<:Real}(x::R) = -x
>
> f1(x::Real) = x
>
> f1 (generic function with 2 methods)
>
> So the methods are kept separate, but I think the first form hides access
> to the second form.
>
IIUC it doesn't really "hide" it, but for a call like f1(1.0) the generic
can be used to generate f1(x::Float64) which is more specific than
f1(x::Real) so it is used instead.
>
> On Monday, December 8, 2014 7:12:39 AM UTC+1, Igor Demura wrote:
>
>> What exactly the difference between:
>> function foo{T<:AbstractType}(x::T) = ...
>> and
>> function foo(x::AbstractType) = ... ?
>> Is any difference at all? The "tips" section of the docs says the second
>> is preferred. If they are the same, why first syntax?
>>
>
See above.
> I can imagine that I can benefit if I have several parameters:
>> function bar{T<:AbstractType}(x::Concrete{T}, y::AnotherOf{T}, z::T) = ...
>>
>>
