# `mix schooner.repl`
[🔗](https://github.com/ausimian/schooner/blob/1.2.0/lib/mix/tasks/schooner.repl.ex#L1)

Starts an interactive session against your application's real
environment, built on `Schooner.Session`. Something that works here
works in production, and something that's unbound in production is
unbound here too.

    $ mix schooner.repl --env MyApp.Scripts.environment
    Schooner 1.1.0 — environment: MyApp.Scripts.environment/0. ,help for commands.
    schooner> (define (with-shipping x)
         ...>   (+ x 5))
    schooner> (with-shipping 30)
    35

Definitions, imports and `define-syntax` macros persist from one
entry to the next. An entry that ends inside an open form continues
on the next line, and in a terminal that line starts indented to
where the code goes, as `Schooner.Pretty` would lay it out: a body
two columns in, the arguments of a call under the first. Tab
re-indents a line, Up and Down recall earlier entries, and Ctrl-C
interrupts an evaluation that runs too long, leaving the session as
it was before it. Ctrl-D or `,quit` leaves.

An error is printed, and the session carries on.

## Commands

  * `,env [prefix]` — list the bindings in scope, or those whose name
    starts with `prefix`: each one's name, the library it comes from,
    and what it is.
  * `,expand <form>` — show what `<form>` expands to, with the
    session's macros.
  * `,time <form>` — evaluate `<form>` and report its wall time and
    reductions.
  * `,load <file>` — evaluate a file into the session.
  * `,help`, `,quit`.

## Options

  * `--env Mod.fun` — evaluate against the `Schooner.Environment`
    returned by the zero-arity function `Mod.fun`. Without it, the
    environment is the one configured with

        config :schooner, :tooling_environment, {Mod, :fun, args}

    and without that, every standard library, all imported: the
    surface `Schooner.run/1` gives a script that imports nothing.
  * `--load FILE` — evaluate `FILE` into the session before the
    first prompt. Repeat it to load several, in order.
  * `--debug` — evaluate with `debug: true`, so errors carry their
    location and a Scheme backtrace.

When standard input isn't a terminal, the task reads whole lines,
without editing or indenting them, so you can pipe a script in.
Ctrl-C then reaches the BEAM, as in any other mix task.

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*Consult [api-reference.md](api-reference.md) for complete listing*