View Source Dune.Session (dune v0.3.11)

Sessions provide a way to evaluate code and keep state (bindings, modules...) between evaluations.

Dune.Session could be used to implement something like a safe IEx shell, or to compile a module once and call it several times without the overhead of parsing.

Dune.Session is also a struct that is used to store the state of an evaluation.

Only the following fields are public:

  • last_result: contains the result of the last evaluation, or nil for empty sessions

Other fields are private and shouldn't be accessed directly.

Summary

Types

private_compile_env()
private_env()
t()

The type of a Dune.Session.

Functions

eval_string(session, string, opts \\ [])

Evaluates the provided string in the context of the session and returns a new session.

new()

Returns a new empty session.

Types

private_compile_env()

@opaque private_compile_env()

private_env()

@opaque private_env()

t()

@type t() :: %Dune.Session{
  bindings: keyword(),
  compile_env: private_compile_env(),
  env: private_env(),
  last_result: nil | Dune.Success.t() | Dune.Failure.t()
}

The type of a Dune.Session.

Functions

eval_string(session, string, opts \\ [])

@spec eval_string(t(), String.t(), keyword()) :: t()

Evaluates the provided string in the context of the session and returns a new session.

The result will be available in the last_result key. In case of a success, the variable bindings or created modules will be saved in the session. In case of a failure, the rest of the session state won't be updated, so it is possible to keep executing instructions after a failure

Examples 

iex> Dune.Session.new()
...> |> Dune.Session.eval_string("x = 1")
...> |> Dune.Session.eval_string("x + 2")
#Dune.Session<last_result: %Dune.Success{value: 3, inspected: "3", stdio: ""}, ...>

iex> Dune.Session.new()
...> |> Dune.Session.eval_string("x = 1")
...> |> Dune.Session.eval_string("x = x / 0")  # will fail, but the previous state is kept
...> |> Dune.Session.eval_string("x + 2")
#Dune.Session<last_result: %Dune.Success{value: 3, inspected: "3", stdio: ""}, ...>

new()

@spec new() :: t()

Returns a new empty session.

Examples 

iex> Dune.Session.new()
#Dune.Session<last_result: nil, ...>