lua-5.1.1中的动态类型的实现

ltypes.h

/*
** basic types
*/
#define LUA_TNONE	(-1)

#define LUA_TNIL	0
#define LUA_TBOOLEAN	1
#define LUA_TLIGHTUSERDATA	2        //void *
#define LUA_TNUMBER	3                        //lua3后采用double精度表示数字整型
#define LUA_TSTRING	4                        //TString
#define LUA_TTABLE	5                        //Table
#define LUA_TFUNCTION	6                //CClosure、LClosure
#define LUA_TUSERDATA	7                //void *
#define LUA_TTHREAD	8                        //协程

#define CommoHeader GCObject *next; lu_byte tt; lu_byte marked

/*
** Common header in struct form
*/
typedef struct GCheader {
    CommonHeader;
} GCheader;

/*
** Union of all collectable objects
*/
union GCObject {
  GCheader gch;
  union TString ts;
  union Udata u;
  union Closure cl;
  struct Table h;
  struct Proto p;
  struct UpVal uv;
  struct lua_State th;  /* thread */
};

/*
** Union of all Lua values
*/
typedef union {
  GCObject *gc;
  void *p;//LUA_TLIGHTUSERDATA
  lua_Number n;//LUA_TNUMBER
  int b;//LUA_TBOOLEAN
} Value;

/*
** Tagged Values
*/
#define TValuefields	Value value; int tt

typedef struct lua_TValue {
  TValuefields;
} TValue;

/* Macros to set values */
#define setnilvalue(obj) ((obj)->tt=LUA_TNIL)

#define setnvalue(obj,x) \
  { TValue *i_o=(obj); i_o->value.n=(x); i_o->tt=LUA_TNUMBER; }

#define setpvalue(obj,x) \
  { TValue *i_o=(obj); i_o->value.p=(x); i_o->tt=LUA_TLIGHTUSERDATA; }

#define setbvalue(obj,x) \
  { TValue *i_o=(obj); i_o->value.b=(x); i_o->tt=LUA_TBOOLEAN; }

#define setsvalue(L,obj,x) \
  { TValue *i_o=(obj); \
    i_o->value.gc=cast(GCObject *, (x)); i_o->tt=LUA_TSTRING; \
    checkliveness(G(L),i_o); }

#define setuvalue(L,obj,x) \
  { TValue *i_o=(obj); \
    i_o->value.gc=cast(GCObject *, (x)); i_o->tt=LUA_TUSERDATA; \
    checkliveness(G(L),i_o); }

#define setthvalue(L,obj,x) \
  { TValue *i_o=(obj); \
    i_o->value.gc=cast(GCObject *, (x)); i_o->tt=LUA_TTHREAD; \
    checkliveness(G(L),i_o); }

#define setclvalue(L,obj,x) \
  { TValue *i_o=(obj); \
    i_o->value.gc=cast(GCObject *, (x)); i_o->tt=LUA_TFUNCTION; \
    checkliveness(G(L),i_o); }

#define sethvalue(L,obj,x) \
  { TValue *i_o=(obj); \
    i_o->value.gc=cast(GCObject *, (x)); i_o->tt=LUA_TTABLE; \
    checkliveness(G(L),i_o); }

#define setptvalue(L,obj,x) \
  { TValue *i_o=(obj); \
    i_o->value.gc=cast(GCObject *, (x)); i_o->tt=LUA_TPROTO; \
    checkliveness(G(L),i_o); }

#define setobj(L,obj1,obj2) \
  { const TValue *o2=(obj2); TValue *o1=(obj1); \
    o1->value = o2->value; o1->tt=o2->tt; \
    checkliveness(G(L),o1); }

ltypes.md

ltypes

这是从lua-5.1.1中分离出来的动态类型实现代码。

关于lua动态类型

lua数据类型