The only reference I can find in the manual to the `const` keyword is in
the performance section [1]. Well, that and the `isconst` function[2].
This seems like it would be worth documenting, especially since it behaves
significantly differently than the const that I remember from Java or C++,
which prevented you from changing the value of const variable.
I think I understand now, that `const` in Julia means that the type of the
variable must remain constant. This was very surprising to me.
~~~.jl
julia> const x = 10
10
julia> x += 1
Warning: redefining constant x
11
julia> x
11
julia> const arr = Int[1,2,3]
3-element Array{Int64,1}:
1
2
3
julia> arr[1] = 13
13
julia> arr
3-element Array{Int64,1}:
13
2
3
julia> x += 0.5
ERROR: invalid redefinition of constant x
~~~
I'd be happy to add this to the manual, but I'm not sure where it belongs.
Any suggestions?
1:
http://docs.julialang.org/en/latest/manual/performance-tips/?highlight=const#avoid-global-variables
2:
http://docs.julialang.org/en/latest/stdlib/base/?highlight=const#Base.isconst
