What does the output of this IO.puts mean?
IO.puts(a=1)
1
:ok
but
a = 1
1
When executing in iex:
iex> a = 1
1
You see the result of the operation, which is 1.
When executing:
iex> IO.puts(a=1)
1
:ok
You see the result of the operation, which is :ok, but you also see 1 that you printed (wrote to :stdio).
In the docs, you can read that IO.puts/2 returns :ok in case of success.
https://hexdocs.pm/elixir/IO.html#puts/2
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You should also notice that the 1 is plain colored and the :ok is colored by elixir’s pretty print, indicating it’s a evaluation output and not a print to screen, which can only be colored explicitly.
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