Q:

How to pass parameter list to a function in Julia

I am newbie in Julia language, and the tutorial is not very deep yet and I didn't understand what is the best way to pass a parameter list of a function. My function looks like this:
function dxdt(x)
    return a*x**2 + b*x - c
end

where x is the variable (2D array) and a,c, and d are parameters. As I understand it is not recommended to work with global variables in Julia. So what is the right way to do it?

A:

The idiomatic solution would be to create a type to hold the parameters and use multiple dispatch to call the correct version of the function.
Here's what I might do
type Params
    a::TypeOfA
    b::TypeOfB
    c::TypeOfC
end

function dxdt(x, p::Params)
    p.a*x^2 + p.b*x + p.c
end

Sometimes if a type has many fields, I define a helper function _unpack (or whatever you want to name it) that looks like this:
_unpack(p::Params) = (p.a, p.b, p.c)

And then I could change the implementation of dxdt to be 
function dxdt(x, p::Params)
    a, b, c = _unpack(p)
    a*x^2 + b*x + c
end

