Merge branch 'master' of github.com:MarcusTL12/JuliaKursPVV

2019/Julia/Code/11.structs2.jl

@@ -0,0 +1,27 @@
+
+# This is just a super simple example to illustrate the "call" operator.
+
+# Simple polynomial type. The Polynomials.jl package is basically a more
+# complete version of this example.
+struct Poly{T}
+    coeffs::Vector{T}
+end
+
+# Could implement a whole bunch of operators (+, -, *, /, show, etc.)
+# but that can be left as an exercise for the reader :3
+# Also the Polynomials.jl package have implemented most of those.
+
+# Here, the whole point of this example; This function basically makes
+# the variable, p, act as a polynomial function on x.
+function (p::Poly{T})(x::T) where T <: Number
+    ret = zero(T)
+    for i in 1 : length(p.coeffs)
+        ret += p.coeffs[i] * x^(i - 1)
+    end
+    ret
+end
+
+# Now any variable of type Poly can be used as if it was a function
+# This gives some really clean syntax :)
+p = Poly([0.0, -3.0, 0.0, 1.0]) # p = 0 - 3 x + 0 x^2 + 1 x^3
+@show p(3.0)