Elixir Code Formatter

mix format is the official Elixir code formatter, introduced in Elixir 1.6. It parses source into an AST and pretty-prints it back using a single, deterministic style. Because every Elixir project shares the same conventions, teams stop arguing about whitespace, code reviews focus on logic instead of layout, and diffs stay clean across editors and operating systems.

The pipe operator passes the value on its left as the first argument to the function on its right. So data |> transform() |> save() is equivalent to save(transform(data)). Pipes read top-to-bottom in the order operations happen, which is why idiomatic Elixir places each |> on its own line indented two spaces from the value being piped.

Elixir variables are rebindings, not mutations. x = 1 followed by x = 2 creates a new binding of the name x; the original value 1 still exists in memory until garbage-collected. Inside pattern matches, = is the match operator, not assignment, which is why {:ok, value} = result destructures and binds simultaneously.

def foo do ... end is the multi-line block form, where the body can contain any number of expressions. def foo, do: expr is the keyword-list shorthand for a single-expression body and is parsed as a 2-tuple {:do, expr} in a keyword list. Both produce identical bytecode; the shorthand is preferred for one-liners and the block form for multi-statement bodies.

A double-quoted string is a UTF-8 binary — a sequence of bytes. A single-quoted charlist is a linked list of Unicode codepoints, inherited from Erlang where strings are traditionally lists of integers. Most Elixir APIs (Phoenix, Ecto, Plug) work with binaries; charlists mainly appear at Erlang interop boundaries (:inets, :gen_tcp, etc.) where the underlying library expects lists.