View Source Lua (Lua v0.0.3)
Lua is an ergonomic interface to Luerl, aiming to be the best way to use Luerl from Elixir.
Features
- Ergonomic API for Elixir <> Lua FFI
- Improved error messages
- Deep-setting variables and state
- Excellent documentation and guides for working with Luerl
Executing Lua
Lua can be run using the eval!/2
function
iex> {[4], _} =
...> Lua.eval!("""
...> return 2 + 2
...> """)
Exposing Elixir functions to Lua
Lua
provides the deflua
macro for exposing Elixir functions to Lua
defmodule MyAPI do
use Lua.API
deflua double(v), do: 2 * v
end
lua = Lua.new() |> Lua.load_api(MyAPI)
{[10], _} =
Lua.eval!(lua, """
return double(5)
""")
Credits
Lua piggy-backs off of Robert Virding's Luerl project, which implements an Lua lexer, parser, and full-blown lua virtual machine that runs inside the BEAM.
Summary
Functions
Evalutes the script or chunk, returning the result and discarding side effects in the state
Gets a table value in Lua
Inject functions written with the deflua
macro into the Lua
runtime
Initializes a Lua VM sandbox. All library functions are stubbed out, so no access to the filesystem or the execution environment is exposed.
Sandboxes the given path, swapping out the implementation with a function that raises when called
Sets a table value in Lua. Nested keys will create intermediate tables
Sets the path patterns that Lua will look in when requiring Lua scripts.
Functions
Evalutes the script or chunk, returning the result and discarding side effects in the state
Gets a table value in Lua
iex> state = Lua.set!(Lua.new(), [:hello], "world")
iex> Lua.get!(state, [:hello])
"world"
When a value doesn't exist, it returns nil
iex> Lua.get!(Lua.new(), [:nope])
nil
It can also get nested values
iex> state = Lua.set!(Lua.new(), [:a, :b, :c], "nested")
iex> Lua.get!(state, [:a, :b, :c])
"nested"
Inject functions written with the deflua
macro into the Lua
runtime
Initializes a Lua VM sandbox. All library functions are stubbed out, so no access to the filesystem or the execution environment is exposed.
Options
:sandboxed
- list of paths to be sandboxed, e.g.sandboxed: [[:require], [:os, :exit]]
Sandboxes the given path, swapping out the implementation with a function that raises when called
iex> lua = Lua.new(sandboxed: [])
iex> Lua.sandbox(lua, [:os, :exit])
Sets a table value in Lua. Nested keys will create intermediate tables
iex> Lua.set!(Lua.new(), [:hello], "World")
It can also set nested values
iex> Lua.set!(Lua.new(), [:a, :b, :c], [])
These table values are availble in lua scripts
iex> lua = Lua.set!(Lua.new(), [:a, :b, :c], "nested!")
iex> {result, _} = Lua.eval!(lua, "return a.b.c")
iex> result
["nested!"]
Sets the path patterns that Lua will look in when requiring Lua scripts.