That's what I ended up doing but keyword arguments have the advantage of
being self-documenting. Thanks for the explanations.
On Friday, March 25, 2016 at 10:07:54 PM UTC-4, Greg Plowman wrote:
>
> Thanks Matt, that helps my understanding of keyword arguments.
>
> It also occurs to me that if you don't really require *keyword* arguments
> then you could define as:
>
> function g(s::AbstractString)
> println(s)
> end
>
> function g{S<:AbstractString}(s::AbstractString, v::Vector{S})
> println(s)
> for e in v
> println(e)
> end
> end
>
> and call as:
>
> julia> g("boo")
> boo
>
> julia> g("bla", ["foo", "bar"])
> bla
> foo
> bar
>
>
>
> On Saturday, March 26, 2016 at 10:43:17 AM UTC+11, Matt Bauman wrote:
>
>> There's a few things going on here. First, you only define one method
>> for `g` — your second definition overwrites the first because keyword
>> arguments don't participate in multiple dispatch. There's been a warning
>> added here in 0.5.
>>
>> So the one method you define just takes one argument and one keyword
>> argument. That's why `g("bla", ["foo", "bar"])` isn't working. If you
>> instead call `g("bla", v=["foo", "bar"])`, you'll get a stack overflow
>> error with the second definition, and a type assertion failure with the
>> first. Instead of converting your `v` argument to a
>> `Vector{AbstractArray}`, you can just use the first definition with a type
>> parameter.
>>
>> Finally, the `S not defined` error is a known surprising behavior:
>> https://github.com/JuliaLang/julia/issues/15613. When there's no
>> keyword argument given, how can Julia know what `S` should be?
>>
>> On Friday, March 25, 2016 at 7:15:09 PM UTC-4, Dominique Orban wrote:
>>>
>>> I (think I) understand the issue in this thread:
>>> https://groups.google.com/forum/#!searchin/julia-users/AbstractString/julia-users/HBMDbnRTH9g/cuqa6hB8AQAJ
>>> but I have the same problem with a keyword argument:
>>>
>>> function g(s :: AbstractString; v :: Vector{AbstractString}=
>>> AbstractString[])
>>> println(s)
>>> for e in v
>>> println(v)
>>> end
>>> end
>>>
>>>
>>> I need to dispatch on the optional argument `v`, so:
>>>
>>> g{S <: AbstractString}(s :: AbstractString; v :: Vector{S}=Vector{S}[])
>>> = g(s, v=convert(Vector{AbstractString}, v))
>>>
>>>
>>>
>>> but unfortunately:
>>>
>>> julia> g("bla", ["foo", "bar"])
>>> ERROR: MethodError: `g` has no method matching g(::ASCIIString, ::Array{
>>> ASCIIString,1})
>>> Closest candidates are:
>>> g(::AbstractString)
>>>
>>>
>>> Moreover,
>>>
>>> julia> g("boo")
>>> ERROR: UndefVarError: S not defined
>>>
>>>
>>> Any ideas?
>>>
>>
