class Rufus::Lua::State
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
Public Class Methods
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.
This optional arg can be set to false, when no libs should be present, or to an array of libs to load in order to prepare the state.
The list may include 'base', 'package', 'table', 'string', 'math', 'io', 'os' and 'debug'.
# File lib/rufus/lua/state.rb, line 377 def initialize(include_libs=true) @pointer = Lib.luaL_newstate open_libraries(include_libs) # # preparing library methods cache class << @pointer attr_reader :__lib_method_cache end @pointer.instance_variable_set(:@__lib_method_cache, {}) # # an array for preserving callback (Ruby functions) from Ruby # garbage collection (Scott). @callbacks = [] @error_handler = 0 end
Public Instance Methods
Returns a value set at the 'global' level in the state.
state.eval('a = 1 + 2') puts state['a'] # => "3.0"
# File lib/rufus/lua/state.rb, line 441 def [](k) k.index('.') ? self.eval("return #{k}") : get_global(k) end
Allows for setting a Lua
varible immediately.
state['var'] = [ 1, 2, 3 ] puts state['var'].to_a[0] # => 1
# File lib/rufus/lua/state.rb, line 451 def []=(k, v) #puts; puts("#{k} = #{Rufus::Lua.to_lua_s(v)}") self.eval("#{k} = #{Rufus::Lua.to_lua_s(v)}") end
Closes the state.
It's probably a good idea (mem leaks) to close a Lua
state once you're done with it.
# File lib/rufus/lua/state.rb, line 574 def close fail 'State already closed' unless @pointer Lib.lua_close(@pointer) @pointer = nil end
Evaluates a piece (string) of Lua
code within the state.
# File lib/rufus/lua/state.rb, line 431 def eval(s, bndng=nil, filename=nil, lineno=nil) loadstring_and_call(s, bndng, filename, lineno) end
Binds a Ruby function (callback) in the top environment of Lua
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
:to_ruby => true¶ ↑
Without this option set to true, Lua
tables passed to the wrapped Ruby code are instances of Rufus::Lua::Table
. With this option set, rufus-lua will call to_ruby on any parameter that responds to it (And Rufus::Lua::Table
does).
s = Rufus::Lua::State.new s.function 'is_array', :to_ruby => true do |table| table.is_a?(Array) end s.eval(return is_array({ 1, 2 })) # => true s.eval(return is_array({ 'a' = 'b' })) # => false
# File lib/rufus/lua/state.rb, line 498 def function(name, opts={}, &block) fail 'please pass a block for the body of the function' unless block to_ruby = opts[:to_ruby] callback = Proc.new do |state| s = CallbackState.new(state) args = [] loop do break if s.stack_top == 0 # never touch stack[0] !! arg = s.stack_fetch args.unshift(arg) s.stack_unstack unless args.first.is_a?(Rufus::Lua::Ref) end while args.size < block.arity args << nil end args = args.collect { |a| a.respond_to?(:to_ruby) ? a.to_ruby : a } \ if to_ruby s.stack_push(block.call(*args)) 1 end @callbacks << callback # preserving the callback from garbage collection 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
Runs garbage collection
# File lib/rufus/lua/state.rb, line 591 def gc_collect! fail 'State got closed, cannot proceed' unless @pointer Lib.lua_gc(@pointer, LUA_GCCOLLECT, 0) end
Returns current amount of memory in KB in use by Lua
# File lib/rufus/lua/state.rb, line 583 def gc_count fail 'State got closed, cannot proceed' unless @pointer Lib.lua_gc(@pointer, LUA_GCCOUNT, 0) end
Restart garbage collection for this state
# File lib/rufus/lua/state.rb, line 607 def gc_resume fail 'State got closed, cannot proceed' unless @pointer Lib.lua_gc(@pointer, LUA_GCRESTART, 0) end
Stop garbage collection for this state
# File lib/rufus/lua/state.rb, line 599 def gc_stop fail 'State got closed, cannot proceed' unless @pointer Lib.lua_gc(@pointer, LUA_GCSTOP, 0) end
# File lib/rufus/lua/state.rb, line 637 def open_libraries(libs) if libs == true Lib.luaL_openlibs(@pointer) elsif libs.is_a?(Array) libs.each { |l| open_library(l) } end end
open_library(libname)
- load a lua library via lua_call().
This is needed because is the Lua
5.1 Reference Manual Section 5 (www.lua.org/manual/5.1/manual.html#5) it says:
βThe luaopen_* functions (to open libraries) cannot be called directly, like a regular C function. They must be called through Lua
, like a Lua
function.β
β..you must call them like any other Lua
C function, e.g., by using lua_call.β
(by Matthew Nielsen - github.com/xunker)
# File lib/rufus/lua/state.rb, line 627 def open_library(libname) Lib.lua_pushcclosure( @pointer, lambda { |ptr| Lib.send("luaopen_#{libname}", @pointer) }, 0) Lib.lua_pushstring( @pointer, (libname.to_s == "base" ? "" : libname.to_s)) Lib.lua_call( @pointer, 1, 0) end
# File lib/rufus/lua/state.rb, line 400 def set_error_handler(lua_code=nil, &block) if lua_code == nil && block function('_ruby_error_handler', &block) stack_load_path('_ruby_error_handler') @error_handler = stack_top elsif lua_code == nil Lib.lua_remove(@pointer, @error_handler) if @error_handler > 0 @error_handler = 0 elsif lua_code == :traceback stack_load_path('debug.traceback') @error_handler = stack_top else lua_code = lua_code.strip lua_code = 'return ' + lua_code unless lua_code.match(/^return\s+/) r = self.eval(lua_code) r.send(:load_onto_stack) @error_handler = stack_top end end