Class: Rufus::Lua::Table

Inherits:
Ref
  • Object
show all
Includes:
Enumerable
Defined in:
lib/rufus/lua/objects.rb

Overview

A Lua table.

For now, the only thing you can do with it is cast it into a Hash or an Array (will raise an exception if casting to an Array is not possible).

Note that direct manipulation of the Lua table (inside Lua) is not possible (as of now).

Constant Summary

Constants included from StateMixin

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

Instance Attribute Summary

Attributes inherited from Ref

#ref

Instance Method Summary collapse

Methods inherited from Ref

#free, #initialize

Constructor Details

This class inherits a constructor from Rufus::Lua::Ref

Instance Method Details

#[](k) ⇒ Object

Returns the value behind the key, or else nil.



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# File 'lib/rufus/lua/objects.rb', line 178

def [] (k)

  load_onto_stack # table
  stack_push(k) # key
  Lib.lua_gettable(@pointer, -2) # fetch val for key at top and table at -2
  stack_pop
end

#[]=(k, v) ⇒ Object

Sets a value in the table

TODO : have something for adding in the array part…



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# File 'lib/rufus/lua/objects.rb', line 190

def []= (k, v)

  load_onto_stack

  stack_push(k)
  stack_push(v)
  Lib.lua_settable(@pointer, -3)

  v
end

#each ⇒ Object

The classical ‘each’.

Note it cheats by first turning the table into a Ruby Hash and calling the each of that Hash instance (this way, the stack isn’t involved in the iteration).



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# File 'lib/rufus/lua/objects.rb', line 156

def each

  return unless block_given?
  self.to_h.each { |k, v| yield(k, v) }
end

#keys ⇒ Object

Returns the array of keys of this Table.



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# File 'lib/rufus/lua/objects.rb', line 164

def keys

  self.to_h.keys
end

#objlen ⇒ Object

Returns the size of the table, corresponds to the Lua ‘#’ operator.

Will thus return 0 if the table doesn’t hold any value in its ‘array’ part.



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# File 'lib/rufus/lua/objects.rb', line 206

def objlen

  load_onto_stack
  Lib.lua_objlen(@pointer, -1)
end

#size ⇒ Object Also known as: length

Returns the real size of the table (number of entries + number of elements in array side)



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# File 'lib/rufus/lua/objects.rb', line 215

def size

  self.to_h.size
end

#to_a(pure = true) ⇒ Object

Returns a Ruby Array instance representing this Lua table.

Will raise an error if the ‘rendering’ is not possible.

s = Rufus::Lua::State.new

@s.eval("return { a = 'A', b = 'B', c = 3 }").to_a
  # => error !

@s.eval("return { 1, 2 }").to_a
  # => [ 1.0, 2.0 ]

@s.eval("return {}").to_a
  # => []

@s.eval("return { 1, 2, car = 'benz' }").to_a
  # => error !

to_a(false)

Setting the optional argument ‘pure’ to false will manage any table :

s = Rufus::Lua::State.new

@s.eval("return { a = 'A', b = 'B', c = 3 }").to_a(false)
  # => [["a", "A"], ["b", "B"], ["c", 3.0]]

@s.eval("return { 1, 2 }").to_a(false)
  # => [1.0, 2.0]

@s.eval("return {}").to_a(false)
  # => []

@s.eval("return { 1, 2, car = 'benz' }").to_a(false)
  # => [1.0, 2.0, ["car", "benz"]]



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# File 'lib/rufus/lua/objects.rb', line 285

def to_a (pure=true)

  h = self.to_h

  pure && h.keys.find { |k| not [ Float ].include?(k.class) } &&
    raise("cannot turn hash into array, some keys are not numbers")

  a_keys = (1..objlen).to_a.collect { |k| k.to_f }
  keys = a_keys + (h.keys - a_keys)

  keys.inject([]) { |a, k|
    a << (a_keys.include?(k) ? h[k] : [ k, h[k] ])
    a
  }
end

#to_h ⇒ Object

Returns a Ruby Hash instance representing this Lua table.



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# File 'lib/rufus/lua/objects.rb', line 223

def to_h

  load_onto_stack

  table_pos = stack_top

  Lib.lua_pushnil(@pointer)

  h = {}

  while Lib.lua_next(@pointer, table_pos) != 0 do

    value = stack_fetch(-1)
    value.load_onto_stack if value.is_a?(Ref)

    key = stack_fetch(-2)
    key.load_onto_stack if key.is_a?(Ref)

    stack_unstack # leave key on top

    h[key] = value
  end

  h
end

#to_ruby ⇒ Object

Turns the Lua table into a Ruby array, or else into a Ruby Hash instance.



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# File 'lib/rufus/lua/objects.rb', line 303

def to_ruby

  to_a rescue to_h
end

#values ⇒ Object

Returns the array of values in this Table.



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# File 'lib/rufus/lua/objects.rb', line 171

def values

  self.to_h.values
end