How does elixir get around erlang's limitation of not rebinding variables?

Questions / Help
1

Doing some erlang review as it’s been a while since I’ve used it. Something I’ve wondered about. Can someone point me to some code or an explanation of how elixir allows rebinding variables? Also interesting to me and potentially relevant is pin operator implementation.

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2

It just compiles to different variables behind the scenes.

a = 1
a = 2

essentially becomes

a1 = 1
a2 = 2
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3

That makes sense, is it really that simple though? Everything becomes an ordinal version of itself postfixed with a number?

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4

Yes:

iex(1)> defmodule Example do
...(1)>   def test(a) do
...(1)>     a = a * 2
...(1)>     a = a + 1
...(1)>     a
...(1)>   end
...(1)> end
iex(2)> beam = elem(v(), 2)
iex(3)> {:ok, {_, [{'Dbgi', dbgi}]}} = :beam_lib.chunks(beam, ['Dbgi'])
iex(4)> {:debug_info_v1, backend, data} = :erlang.binary_to_term(dbgi)
iex(5)> {:ok, ast} = backend.debug_info(:erlang_v1, Example, data, [])
iex(6)> IO.puts(:erl_prettypr.format(:erl_syntax.form_list(ast)))
#
# ...snip...
#
test(_a@1) ->
    _a@2 = _a@1 * 2,
    _a@3 = _a@2 + 1,
    _a@3.
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