Class: Rufus::Lua::State

Inherits:
Object
  • Object
show all
Includes:
StateMixin
Defined in:
lib/rufus/lua/state.rb

Overview

A Lua state, wraps a Lua runtime.

require 'rufus/lua'
s = Rufus::Lua::State.new
s.eval "a = 1 + 2"

p s['a'] # => 3.0

Constant Summary

Constants included from StateMixin

Rufus::Lua::StateMixin::LUA_ENVIRONINDEX, Rufus::Lua::StateMixin::LUA_GCCOLLECT, Rufus::Lua::StateMixin::LUA_GCCOUNT, Rufus::Lua::StateMixin::LUA_GCCOUNTB, Rufus::Lua::StateMixin::LUA_GCRESTART, Rufus::Lua::StateMixin::LUA_GCSETPAUSE, Rufus::Lua::StateMixin::LUA_GCSETSTEPMUL, Rufus::Lua::StateMixin::LUA_GCSTEP, Rufus::Lua::StateMixin::LUA_GCSTOP, Rufus::Lua::StateMixin::LUA_GLOBALSINDEX, Rufus::Lua::StateMixin::LUA_MULTRET, Rufus::Lua::StateMixin::LUA_NOREF, Rufus::Lua::StateMixin::LUA_REFNIL, Rufus::Lua::StateMixin::LUA_REGISTRYINDEX, Rufus::Lua::StateMixin::SIMPLE_TYPES, Rufus::Lua::StateMixin::TBOOLEAN, Rufus::Lua::StateMixin::TFUNCTION, Rufus::Lua::StateMixin::TLIGHTUSERDATA, Rufus::Lua::StateMixin::TNIL, Rufus::Lua::StateMixin::TNONE, Rufus::Lua::StateMixin::TNUMBER, Rufus::Lua::StateMixin::TSTRING, Rufus::Lua::StateMixin::TTABLE, Rufus::Lua::StateMixin::TTHREAD, Rufus::Lua::StateMixin::TUSERDATA

Instance Method Summary collapse

Constructor Details

#initialize(include_libs = true) ⇒ State

Instantiates a Lua state (runtime).

Accepts an ‘include_libs’ optional arg. When set to true (the default, all the base Lua libs are loaded in the runtime.



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# File 'lib/rufus/lua/state.rb', line 384

def initialize (include_libs=true)

  @pointer = Lib.luaL_newstate

  Lib.luaL_openlibs(@pointer) if include_libs

  #
  # preparing library methods cache

  class << @pointer
    attr_reader :__lib_method_cache
  end
  @pointer.instance_variable_set(:@__lib_method_cache, {})
end

Instance Method Details

#[](k) ⇒ Object

Returns a value set at the ‘global’ level in the state.

state.eval('a = 1 + 2')
puts state['a'] # => "3.0"



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# File 'lib/rufus/lua/state.rb', line 413

def [] (k)

  k.index('.') ? self.eval("return #{k}") : get_global(k)
end

#close ⇒ Object

Closes the state.

It’s probably a good idea (mem leaks) to close a Lua state once you’re done with it.



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# File 'lib/rufus/lua/state.rb', line 503

def close

  raise "State already closed" unless @pointer
  Lib.lua_close(@pointer)
  @pointer = nil
end

#eval(s) ⇒ Object

Evaluates a piece (string) of Lua code within the state.



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# File 'lib/rufus/lua/state.rb', line 402

def eval (s)

  loadstring_and_call(s)
end

#function(name, &block) ⇒ Object

Binds a Ruby function (callback) in the top environment of Lua

require 'rubygems'
require 'rufus/lua'

s = Rufus::Lua::State.new

s.function 'key_up' do |table|
  table.inject({}) do |h, (k, v)|
    h[k.to_s.upcase] = v
  end
end

p s.eval(%{
  local table = {}
  table['CoW'] = 2
  table['pigs'] = 3
  table['DUCKS'] = 'none'
  return key_up(table)
}).to_h
  # => { 'COW' => 2.0, 'DUCKS => 'none', 'PIGS' => 3.0 }

s.close



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# File 'lib/rufus/lua/state.rb', line 443

def function (name, &block)

  raise 'please pass a block for the body of the function' unless block

  callback = Proc.new do |state|

    args = block.arity > 0 ?
      (1..block.arity).collect { |i| stack_pop } :
      []

    result = block.call(*args)

    if result.is_a?(Hash)
      stack_push(result)
      1
    else
      result = Array(result)
      result.each { |e| stack_push(e) }
      result.size
    end
  end

  name = name.to_s

  name, index = if ri = name.rindex('.')
    #
    # bind in the given table

    table_name = name[0..ri-1]

    t = self.eval("return #{table_name}") rescue nil

    raise ArgumentError.new(
      "won't create automatically nested tables"
    ) if (not t) and table_name.index('.')

    t = self.eval("#{table_name} = {}; return #{table_name}") \
      unless t

    t.send(:load_onto_stack)

    [ name[ri+1..-1], -2 ]

  else
    #
    # bind function at the global level

    [ name, LUA_GLOBALSINDEX ]
  end

  Lib.lua_pushcclosure(@pointer, callback, 0)
  Lib.lua_setfield(@pointer, index, name)
end

#gc_collect! ⇒ Object

Runs garbage collection



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# File 'lib/rufus/lua/state.rb', line 522

def gc_collect!

  raise "State got closed, cannot proceed" unless @pointer
  Lib.lua_gc(@pointer, LUA_GCCOLLECT, 0)
end

#gc_count ⇒ Object

Returns current amount of memory in KB in use by Lua



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# File 'lib/rufus/lua/state.rb', line 513

def gc_count

  raise "State got closed, cannot proceed" unless @pointer
  Lib.lua_gc(@pointer, LUA_GCCOUNT, 0)
end

#gc_resume ⇒ Object

Restart garbage collection for this state



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# File 'lib/rufus/lua/state.rb', line 540

def gc_resume

  raise "State got closed, cannot proceed" unless @pointer
  Lib.lua_gc(@pointer, LUA_GCRESTART, 0)
end

#gc_stop ⇒ Object

Stop garbage collection for this state



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# File 'lib/rufus/lua/state.rb', line 531

def gc_stop

  raise "State got closed, cannot proceed" unless @pointer
  Lib.lua_gc(@pointer, LUA_GCSTOP, 0)
end