lualubit Description

Project LUALUBIT implements bitwise operators into Lua programming language directly into core code instead of library module.
Based on :

• http://www.lua.org/ftp/lua-5.2.0.tar.gz
• http://www.lua.org/work/lua-5.2.0-beta.tar.gz 2011-07-08
• http://www.wra1th.plus.com/lua/risclua.html

Local Download Link lualubit.zip

History

• 0:06 2012-01-08

  new release Lua 5.2 was released, native bitwise operatos no implemented, that`s why:

  Rework of lualubit for release Lua 5.2 source code
  http://sourceforge.net/projects/lualubit/files/
  
  • created directories
    • release_5.2
      actual release
    • beta_5.2
      first realease of lualubit
  • support homepage of project lualubit
    • http://www.sbmintegral.sk/lua/ (this page)
    • detailed view of changes original Lua release 5.2 source code to embedd native bitwise operators:
      Compare C:\JS_KRESREAL\HBP_konverzia\lua and C:\JS_LUA\lua-5.2.0\src
    • all relevent changes are dependent only on #define GCW_BIT
      remark it - (//#define GCW_BIT) ... and You have original pure Lua release 5.2
      let it unremarked ... and You have (after recompilation) Lua with embedded native bitwise operators
    • brief explanation (and test of lualubit) of the bitwise operators console output of lubit_expl.lua
  • potencial problems of project lualubit

    • operators symetry problem: ( ^ in Lua is power x^y operator, that's why cannot be used for XOR )
          logical         bitwise
      	and    &&       and  &
      	or     ||       or   |
      	xor       (^^)  xor  ^^ (^)   (power operator x**y) ?  	
      	logical xor is equivalent in C(no logical xor opp): (!a)^(!b), returns 0,1
      					 

    • using booleans in arithmetic problem: ( standart Lua has strictly separated booleans and numbers )
          in lualubit is added conversion function
      	const TValue *luaV_toboolnumber (const TValue *obj, TValue *n)
      	which allow use booleans and numbers in arithmetics: 
      		ONLY FOR ADDED OPERATORS ... #ifndef GCW_ALLOW_BOOL_IN_ARITHMETIC
      		FOR ALL ARITHM. OPERATORS ... #ifdef GCW_ALLOW_BOOL_IN_ARITHMETIC
      					 

    • using nil in arithmetic problem: ( standart Lua does not allow use nill in arithmetics)
      	added logical operators ( && || ! ) work like a arithm. operators, returns 0,1
      	but standart Lua logical operators ( and or not ) works like control structure operators.
      	Recomendation: all is OK, assignments must be checked before arithm.operation.
      					 

    • common problem - why use NEW BITWISE AND LOGICAL OPERATORS: 
      	Personal view:
      		Each programming language, I ever work in, has bitwise operators,
      	and logical operators returning explicitly 0,1/false,true (instead of any number).
          ( assembler,Basic,C,C++,JavaScript,PHP,Perl,Python ... (My)SQL !!! ).
      	    And ... I think, Lua is not far away from these languages. (Jan)
      					 

• 13:04 2011-11-02

  In newest Lua 5.2 beta is implemented UNSIGNED INTEGER type and library bit32 for bitwise operations. BEAUTIFULL !

  But I don't like write
  	a = bit32.bor(bit32.band(5,2345),bit32.band(23,7))
  instead of
  	a = 5 & 2345 | 23 & 7
  that's why I rework source codes ( lua-5.2.0-beta.tar.gz [NEW] 	2011-07-08 
  								http://www.lua.org/work/lua-5.2.0-beta.tar.gz )
  to use "native" operators (based on http://www.wra1th.plus.com/lua/risclua.html source code) :
  	band    &
  	bor     |
  	bxor    ^^
  	lshift  <<
  	rshift  >>
  	bnot    ~
  and additional logical operators :
  	land     &&
  	lor      ||
  	lnot     !
  	
  
  All source code changes are dependent on (luaconfig.h) 
  #define GCW_BIT
  /*
  GCW_BIT: Use bit library.
  This extends virtual machine with bitwise operations
  &,|, ^^, ~, <<, >> and provides corresponding events.
  Warning! Makes code non-portable.
  Affects c.lvm, c.lcode, c.lopcodes, c.ltm
  c.llex, c.lparser, h.lcode, h.lopcodes
  h.ltm, h.llex, h.luaconf.
   
  additionally NUM_logical operators ( return numerical (1,0), not boolean values )
  !,&&,||
  */
  
  IMPORTANT:   in standart Lua is not possible use boolean (true,false) in arithmetical operations,
  but I need it. 
  On (lvm.c line:375) is it possible (unremark) allow using booleans only for new operators.
  ------------------------------
  Need tests, if all is correct.
  ------------------------------