# Elixir

[docker-environment][nextjournal#docker-environment#f00dc296-74c8-4508-860e-a9425ddd241c]

```bash id=859ef006-fe77-40b3-8349-327ec927e925
bash_path="$(which bash)"
cp "$bash_path" /usr/local/bin/real-bash
echo "#!/usr/local/bin/real-bash" > "$bash_path"
echo "shift; shift; shift" >> "$bash_path"
echo "$(which elixir) -e \"\$@\" " >> "$bash_path"
```

Replacing the bash binary with the elixir binary, a common bash cell can be used as elixir interpreter:

```bash id=ccb74431-1db1-465b-a6e0-e2ac2be7c24a
IO.puts "hello elixir"
```

Replacing a python next-repl interpreter with an elixir repl, which loads the repl code from a (transcluded) cell, we can upgrade an elixir interpreter to a next repl, opening a port on 9999 and reading code from it and responding with transit events.

```bash id=723f3bb4-c3e0-43b8-b146-f137142ebcd9
python_path="$(which python)"
echo "#!/usr/bin/env bash" > "$python_path"
echo "$(which elixir) -e \"\$(cat <<EOS 
$(cat <<EOM
[reference][nextjournal#reference#df9569ca-f29e-4772-bb92-8b350fa87a1f]
EOS
EOM
)
)\"" >> "$python_path"
cat $python_path
```

This is the basic nextrepl code:

```bash id=5e2dd663-7073-494d-b50f-e79e4ba7afb1
{:ok, socket} = :gen_tcp.listen(_port = 9999, [:binary, active: false, reuseaddr: true, ip: {0,0,0,0}])
{:ok, client} = :gen_tcp.accept(socket)
tag_write = fn(tag, data) ->
  line = "[\"~:#{tag}\",{}]"
  :gen_tcp.send(client, line)
end
tag_write.('nextrepl/hello', {})
tag_write.('prompt', {})
loop = fn(loop, bindings) ->
  {:ok, data} = :gen_tcp.recv(client, 0)
  IO.puts "received "
  IO.puts inspect(data)
  [reference][nextjournal#reference#130387ec-9535-4752-9765-d0755b50dcfa]
  loop.(loop, bindings)
end
loop.(loop, [])
```

This would be a stateful elixir repl. It does not finish booting yet, 

```python id=19a3147c-9d44-4118-b4a1-dbe9ef27e6f8
1
```

because the eval step is missing, but that would be only some few more lines...

```bash id=6ff15b12-4031-4573-b40e-a2ad04341837
# eval code (to be done)	
{result, bindings} = Code.eval_string(data, bindings)
```

[nextjournal#docker-environment#f00dc296-74c8-4508-860e-a9425ddd241c]:
<https://nextjournal.com>

[nextjournal#reference#df9569ca-f29e-4772-bb92-8b350fa87a1f]:
<#nextjournal#reference#df9569ca-f29e-4772-bb92-8b350fa87a1f>

[nextjournal#reference#130387ec-9535-4752-9765-d0755b50dcfa]:
<#nextjournal#reference#130387ec-9535-4752-9765-d0755b50dcfa>

<details id="com.nextjournal.article">
<summary>This notebook was exported from <a href="https://nextjournal.com/a/CEx27r4BJ5SAUrNTJyo8cg?change-id=CFeSa5pDE3BRzoREwZkfPE">https://nextjournal.com/a/CEx27r4BJ5SAUrNTJyo8cg?change-id=CFeSa5pDE3BRzoREwZkfPE</a></summary>

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</details>