ExMaude.Backend behaviour (ExMaude v0.4.0)

Behaviour for ExMaude communication backends.

All backends must implement this behaviour to be used interchangeably by the ExMaude API. This enables swapping between different communication strategies:

:port - Erlang Port over pipes (default)
:cnode - C bridge over Erlang distribution
:nif - Rustler NIF managing subprocess pipes

Configuration

config :ex_maude,
  backend: :port  # :port | :cnode | :nif

Example

# Get the configured backend module
backend = ExMaude.Backend.impl()

# Start a worker
{:ok, server} = backend.start_link([])

# Execute a command
{:ok, result} = backend.execute(server, "reduce in NAT : 1 + 2 .")

Summary

Types

backend_module()

Backend module types

backend_type()

Backend configuration atoms

command()

result()

Callbacks

alive?(server)

Checks if the backend worker is alive and ready.

execute(server, command, keyword)

Executes a Maude command and returns the result.

load_file(server, path)

Loads a Maude file into the session.

start_link(opts)

Starts a backend worker process.

stop(server)

Stops the backend worker.

Functions

available?(atom)

Checks if a backend is available on this system.

available_backends()

Returns a list of all available backends on this system.

cnode_binary()

Returns the path to the C-Node bridge binary.

impl()

Returns the backend implementation module based on configuration.

Types

backend_module()

@type backend_module() ::
  ExMaude.Backend.Port | ExMaude.Backend.CNode | ExMaude.Backend.NIF

Backend module types

backend_type()

@type backend_type() :: :port | :cnode | :nif

Backend configuration atoms

command()

@type command() :: String.t()

result()

@type result() :: {:ok, String.t()} | {:error, term()}

Callbacks

alive?(server)

@callback alive?(server :: GenServer.server()) :: boolean()

Checks if the backend worker is alive and ready.

execute(server, command, keyword)

@callback execute(server :: GenServer.server(), command(), keyword()) :: result()

Executes a Maude command and returns the result.

Options

:timeout - Maximum time to wait in ms

load_file(server, path)

@callback load_file(server :: GenServer.server(), path :: Path.t()) ::
  :ok | {:error, term()}

Loads a Maude file into the session.

start_link(opts)

@callback start_link(opts :: keyword()) :: GenServer.on_start()

Starts a backend worker process.

Options

:maude_path - Path to Maude executable (optional)
:timeout - Default command timeout in ms
:preload_modules - List of Maude files to load on startup

stop(server)

@callback stop(server :: GenServer.server()) :: :ok

Stops the backend worker.

Functions

available?(atom)

@spec available?(backend_type()) :: boolean()

Checks if a backend is available on this system.

The Port backend is always available. C-Node requires the maude_bridge binary to be compiled. NIF reports available when its native function table has been loaded from either a precompiled binary or a source build (probed via a cheap nif_loaded/0 NIF that raises :nif_not_loaded while the stub is in place).

Examples

ExMaude.Backend.available?(:port)
#=> true

ExMaude.Backend.available?(:cnode)
#=> true if priv/maude_bridge has been compiled

ExMaude.Backend.available?(:nif)
#=> true if the NIF loaded for this platform

available_backends()

@spec available_backends() :: [atom()]

Returns a list of all available backends on this system.

cnode_binary()

@spec cnode_binary() :: Path.t()

Returns the path to the C-Node bridge binary.

impl()

@spec impl() :: backend_module()

Returns the backend implementation module based on configuration.

Reads :backend from the :ex_maude application env (defaults to :port) and maps it to the implementation module.

Examples

ExMaude.Backend.impl()
#=> ExMaude.Backend.Port