Hah, that's clever. We could easily implement required keyword arguments by
making that the default default.
> On Nov 2, 2014, at 3:56 PM, Jameson Nash <vtjn...@gmail.com> wrote:
>
> you could probably come up with better error messages, but the following is
> valid syntax:
>
> julia> f(;a=error("a is required"),b=error("b is required")) = (a,b)
> f (generic function with 1 method)
>
> julia> f(a=1)
> ERROR: b is required
>
> julia> f(a=1,b=4)
> (1,4)
>
> julia> f()
> ERROR: a is required
>
> julia>
>
>
>> On Sun, Nov 2, 2014 at 3:46 PM, Kevin Owens <kevin.j.ow...@gmail.com> wrote:
>> Is there any way to do it without setting default values? Or, is there a
>> type you can give to default values so that if you try to use them it will
>> throw an error? I'm thinking like with R and the "NA" value.
>>
>> Do keyword arguments have to have default values? It's not clear in the 0.3
>> documentation on functions that it's the case.
>>
>>
>>
>>> On Sunday, November 2, 2014 12:47:26 PM UTC-6, Jack Minardi wrote:
>>> You need to give default values for each keyword argument:
>>>
>>> type Foo
>>> bar
>>> baz
>>> Foo(;bar=10, baz=1) = new(bar, baz)
>>> end
>>>
>>>
>>>> On Sunday, November 2, 2014 1:05:37 PM UTC-5, Kevin Owens wrote:
>>>> I'm using Julia 0.3 something.
>>>>
>>>> If I make a composite type with many fields I may forget the order, but
>>>> remember their names. I'd like to use a constructor where I can use name
>>>> the arguments.
>>>>
>>>> Say I have the composite type
>>>>
>>>> type Foo
>>>> bar
>>>> baz
>>>> end
>>>>
>>>> How can I make a constructor that lets me do this
>>>>
>>>> myfoo = Foo(baz=1, bar=2)
>>>>
>>>> I expected this would work
>>>>
>>>>
>>>> type Foo
>>>> bar
>>>> baz
>>>>
>>>> Foo(;bar, baz) = new(bar, baz)
>>>> end
>>>>
>>>> But when I run it I get
>>>>
>>>> ErrorException("syntax: invalid keyword argument bar")
>>>>
>>>> I also tried
>>>>
>>>>
>>>>
>>>> julia> function Foo(;bar, baz)
>>>>
>>>> Foo(bar, baz)
>>>>
>>>> end
>>>>
>>>>
>>>>
>>>> ErrorException("syntax: invalid keyword argument bar")
>
