Related, in Julia0.4 there is also enum:
help?> @enum
.. @enum EnumName EnumValue1[=x] EnumValue2[=y]
Create an :obj:`Enum` type with name ``EnumName`` and enum member values of
``EnumValue1`` and ``EnumValue2`` with optional assigned values of ``x`` and
``y``, respectively. ``EnumName`` can be used just like other types and enum
member values as regular values, such as
.. doctest::
julia> @enum FRUIT apple=1 orange=2 kiwi=3
julia> f(x::FRUIT) = "I'm a FRUIT with value: $(Int(x))"
f (generic function with 1 method)
julia> f(apple)
"I'm a FRUIT with value: 1"
On Tue, 2015-09-15 at 10:51, Michael Borregaard <mkborrega...@gmail.com> wrote:
> Thanks, both, the pattern dispatch package looks useful. I guess the nice
> thing about having the possibilities directly in the arguments line is that
> it is extremely easy for the user to see the legal possible values of the
> argument.
> Best,
> Michael
>
> Den tirsdag den 15. september 2015 kl. 10.44.38 UTC+2 skrev Tomas Lycken:
>>
>> You could also use a fairly common (although it is discouraged in the style
>> guide
>> <http://docs.julialang.org/en/release-0.4/manual/style-guide/?highlight=style#avoid-confusion-about-whether-something-is-an-instance-or-a-type>)
>>
>> construct with an “enum type tree”:
>>
>> abstract SolverMethod
>> immutable Spearman end
>> immutable Pearson end
>> immutable Kendall end
>>
>> Now, you can define and use your function definition like this:
>>
>> function foo{Method<:SolverMethod}(x, method::Type{Method})
>> ...
>> end
>>
>> foo(x, Kendall) # solve using Kendall solver
>>
>> Furthermore, you can leverage multiple dispatch for parts of the function
>> that differ based on the solver method. Inside foo, this
>>
>> if method == "spearman"
>> # do spearman specific stuff
>> elseif method == "pearson"
>> # do pearson specific stuff
>> elseif method == "kendall"
>> # do kendall specific stuff
>> else
>> # handle incorrect input
>> end
>>
>> turns into
>>
>> dostuff(..., method)
>>
>> # and outside of foo
>> function dostuff(..., ::Type{Spearman})
>> # do spearman specific stuff
>> end
>> function dostuff(..., ::Type{Pearson})
>> # do pearson specific stuff
>> end
>> function dostuff(..., ::Type{Kendall})
>> # do kendall specific stuff
>> end
>>
>> //T
>>
>> On Tuesday, September 15, 2015 at 10:32:39 AM UTC+2, Mauro wrote:
>>
>> No, Julia only dispatches on types not on values. The latter sometimes
>>> goes under the name of pattern matching. There is a package for that:
>>> https://github.com/toivoh/PatternDispatch.jl
>>>
>>> On Tue, 2015-09-15 at 10:15, Michael Borregaard <mkborr...@gmail.com>
>>> wrote:
>>> > Is there a way in julia to restrict the values of arguments to a
>>> function,
>>> > eg to the contents of a certain vector?
>>> >
>>> > So, e.g. method in the function
>>> >
>>> > function foo(x, method::String) ...
>>> >
>>> > would be constrained to either "spearman", "pearson" or "kendall"?
>>> >
>>> > Thanks
>>>
>>>
>>
