Is there a root Elixir module?
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Is there a root Elixir module?
When I define a module in Elixir and perform a to_string operation on it like this in IEX
to_string
MyModule |> to_string
MyModule |> to_string
I will get the result,
"Elixir.MyModule"
"Elixir.MyModule"
Is there a root level Elixir module that all other modules live in? Why is there an Elixir prefix that looks like another module?
Elixir
This website says it is a namespace but I have read other articles that say Elixir does not support namespaces.
2 Answers
2
In "Programming Elixir 1.6" Dave Thomas gives this example:
defmodule Outer do
defmodule Inner do
def inner_func do
end
end
def outer_func do
Inner.inner_func
end
end
Outer.outer_func
Outer.Inner.inner_func
defmodule Outer do
defmodule Inner do
def inner_func do
end
end
def outer_func do
Inner.inner_func
end
end
Outer.outer_func
Outer.Inner.inner_func
He then explains:
"Module nesting in Elixir is an illusion—all modules are defined at the top level. When we define a module inside another, Elixir simply prepends the outer module name to the inner module name, putting a dot between the two. This means we can directly define a nested module."
I believe this is for make a difference between Elixir and Erlang modules. All elixir modules are starting with Elixir prefix.MyModule is just an alias for an atom :"Elixir.MyModule":
Elixir
MyModule
:"Elixir.MyModule"
iex(1)> defmodule MyModule, do: def f(), do: "MyModule.f()"
Standard function call:
iex(2)> MyModule.f()
"MyModule.f()"
Erlang-style function call:
iex(3)> :"Elixir.MyModule".f()
"MyModule.f()"
Is the atom equal to alias?
iex(4)> :"Elixir.MyModule" == MyModule
true
iex(5)> :"Elixir.MyModule" == Elixir.MyModule
true
Elixir prefix is for convenience:
Elixir
iex(6)> MyModule == Elixir.MyModule
true
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Sidenote: Elixir does surely support namespaces (well, if we are using the common meaning of “namespaces”.)
– mudasobwa
Aug 9 at 6:59