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Comment by erk__ | Hacker News Reader

What was the reason to choose Elixir over Erlang? Just familiarity with the language?

Not OP, but have used Elixir pretty extensively; the major selling points for me are the friendlier syntax and more active community support, plus with rebar3 + Elixir's seamless Erlang interop you really don't give up anything, you can use any existing Erlang/Elixir libraries with a single syntax. It's pretty great.

Haven't touched Erlang but has an entry level knowledge on Elixir. I often heard how easy it is to write macros on Elixir. Can you elaborate on this?

One of the big differences between Erlang and Elixir is indeed that Elixir allows you to write macros in the language itself, using quote / unquote constructs just like lisps.

This makes it easy to generate code on compile time, which is then executed in runtime without any performance penalty.

A large part of Elixir itself is actually implemented as macros. For instance, the "unless" construct:

  defmacro unless(condition, do: do_clause, else: else_clause) do
    quote do
      if(unquote(condition), do: unquote(else_clause), else: unquote(do_clause))
    end
  end

(code simplified for clarity)

And the if-else construct is also a macro. The whole thing ends up being a case I think.

Imho You shouldn't really write macros, they are there for libraries to make it easy to do the right thing with less boilerplate.

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