Re: [julia-users] Re: When can the broadcast dot (in 0.5) be used?

[Michael Krabbe Borregaard]

That's wonderful news, thanks a lot for this. I know .() is just syntactic
sugar, but to me it really feels intuitive and powerful. Thanks again,
Michael

On Thu, Aug 18, 2016 at 8:27 PM, Steven G. Johnson 
wrote:

> (If you want dot calls to work with your own container type, then you just
> need to make broadcast(...) work.  e.g. here is some discussion for
> ApproxFun: https://github.com/ApproxFun/ApproxFun.jl/issues/356)
>

Re: [julia-users] Re: When can the broadcast dot (in 0.5) be used?

[Steven G. Johnson]

(If you want dot calls to work with your own container type, then you just 
need to make broadcast(...) work.  e.g. here is some discussion for 
ApproxFun: https://github.com/ApproxFun/ApproxFun.jl/issues/356)

Re: [julia-users] Re: When can the broadcast dot (in 0.5) be used?

[Steven G. Johnson]

On Thursday, August 18, 2016 at 2:22:13 PM UTC-4, Michael Borregaard wrote:
>
> It'd be nice with a list of the methods a user-defined type would need to 
> define to be amenable to .() in an Array.
>

In 0.6, once #16966 is ironed out, then you won't have to anything (as long 
as you want your type to be treated as a scalar, not as a container); 
user-defined types will just work with "dot calls".   In 0.5, the dot calls 
are mainly for numeric types (because of the limitations of the "broadcast" 
function).

Re: [julia-users] Re: When can the broadcast dot (in 0.5) be used?

[Michael Krabbe Borregaard]

It'd be nice with a list of the methods a user-defined type would need to
define to be amenable to .() in an Array.

On Thu, Aug 18, 2016 at 8:16 PM, Michael Krabbe Borregaard <
mkborrega...@gmail.com> wrote:

> Thanks! Right now it makes a difference for my understanding just to know
> that this is an issue with String, and that .() will otherwise behave like
> map.
>

Re: [julia-users] Re: When can the broadcast dot (in 0.5) be used?

[Michael Krabbe Borregaard]

Thanks! Right now it makes a difference for my understanding just to know
that this is an issue with String, and that .() will otherwise behave like
map.

Re: [julia-users] Re: When can the broadcast dot (in 0.5) be used?

[Gabriel Gellner]

On Thursday, August 18, 2016 at 10:52:42 AM UTC-7, Michael Borregaard wrote:
>
> That sounds right. I wonder if this is not a bug?
>

>From my reading of the all the related issues, it is a known "issue" ;) It 
looks like a good solution is being ironed out. But I don't think this will 
be added to the 0.5.x timeline, but rather be a 0.6.x feature (along with a 
lot of other amazing .() features!).

For your example you can use the workaround at the moment that map deals 
with this case in the expected manner:

map(x->is(x, "b"), ["a", "b"])

will give the array answer (though likely not what you wanted ...)

Gabriel

Re: [julia-users] Re: When can the broadcast dot (in 0.5) be used?

[Michael Krabbe Borregaard]

That sounds right. I wonder if this is not a bug?

[julia-users] Re: When can the broadcast dot (in 0.5) be used?

[Gabriel Gellner]

My understanding (which can easily be wrong!) is that this stems from 
https://github.com/JuliaLang/julia/issues/16966.
Namely that size("b") throws a method error, whereas your size(2) gives a 
null tuple (). So in general broadcast (which is what the .() is sugar for) 
requires that the element type object that will be vectorizing over has a 
method defined for size.

In general I find Julia's behavior with strings/chars hard to understand. I 
usually just use python when I need to do a lot of string processing.

On Thursday, August 18, 2016 at 7:09:19 AM UTC-7, Michael Borregaard wrote:

> I have a hard time figuring out what functions and types accept the 
> broadcast dot in 0.5. E.g.,
>
> is(1, 2)# false
> is.([1, 2], 2)  # Bool[false, true]
>
> is("a", "b")#false
> is.("["a","b"], "b")#MethodError: no method matching size(::String)
>
> Can anyone give me a hint?
>

[julia-users] Re: When can the broadcast dot (in 0.5) be used?

[Michael Borregaard]

Please ignore the erroneous first " in the last code line.