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
> <javascript:>> 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
>
>
