liblua/lparser.h

   1 /*
   2 ** $Id: lparser.h,v 1.70 2012/05/08 13:53:33 roberto Exp $
   3 ** Lua Parser
   4 ** See Copyright Notice in lua.h
   5 */
   6
   7 #ifndef lparser_h
   8 #define lparser_h
   9
  10 #include "llimits.h"
  11 #include "lobject.h"
  12 #include "lzio.h"
  13
  14
  15 /*
  16 ** Expression descriptor
  17 */
  18
  19 typedef enum {
  20   VVOID,        /* no value */
  21   VNIL,
  22   VTRUE,
  23   VFALSE,
  24   VK,           /* info = index of constant in `k' */
  25   VKNUM,        /* nval = numerical value */
  26   VNONRELOC,    /* info = result register */
  27   VLOCAL,       /* info = local register */
  28   VUPVAL,       /* info = index of upvalue in 'upvalues' */
  29   VINDEXED,     /* t = table register/upvalue; idx = index R/K */
  30   VJMP,         /* info = instruction pc */
  31   VRELOCABLE,   /* info = instruction pc */
  32   VCALL,        /* info = instruction pc */
  33   VVARARG       /* info = instruction pc */
  34 } expkind;
  35
  36
  37 #define vkisvar(k)      (VLOCAL <= (k) && (k) <= VINDEXED)
  38 #define vkisinreg(k)    ((k) == VNONRELOC || (k) == VLOCAL)
  39
  40 typedef struct expdesc {
  41   expkind k;
  42   union {
  43     struct {  /* for indexed variables (VINDEXED) */
  44       short idx;  /* index (R/K) */
  45       lu_byte t;  /* table (register or upvalue) */
  46       lu_byte vt;  /* whether 't' is register (VLOCAL) or upvalue (VUPVAL) */
  47     } ind;
  48     int info;  /* for generic use */
  49     lua_Number nval;  /* for VKNUM */
  50   } u;
  51   int t;  /* patch list of `exit when true' */
  52   int f;  /* patch list of `exit when false' */
  53 } expdesc;
  54
  55
  56 /* description of active local variable */
  57 typedef struct Vardesc {
  58   short idx;  /* variable index in stack */
  59 } Vardesc;
  60
  61
  62 /* description of pending goto statements and label statements */
  63 typedef struct Labeldesc {
  64   TString *name;  /* label identifier */
  65   int pc;  /* position in code */
  66   int line;  /* line where it appeared */
  67   lu_byte nactvar;  /* local level where it appears in current block */
  68 } Labeldesc;
  69
  70
  71 /* list of labels or gotos */
  72 typedef struct Labellist {
  73   Labeldesc *arr;  /* array */
  74   int n;  /* number of entries in use */
  75   int size;  /* array size */
  76 } Labellist;
  77
  78
  79 /* dynamic structures used by the parser */
  80 typedef struct Dyndata {
  81   struct {  /* list of active local variables */
  82     Vardesc *arr;
  83     int n;
  84     int size;
  85   } actvar;
  86   Labellist gt;  /* list of pending gotos */
  87   Labellist label;   /* list of active labels */
  88 } Dyndata;
  89
  90
  91 /* control of blocks */
  92 struct BlockCnt;  /* defined in lparser.c */
  93
  94
  95 /* state needed to generate code for a given function */
  96 typedef struct FuncState {
  97   Proto *f;  /* current function header */
  98   Table *h;  /* table to find (and reuse) elements in `k' */
  99   struct FuncState *prev;  /* enclosing function */
 100   struct LexState *ls;  /* lexical state */
 101   struct BlockCnt *bl;  /* chain of current blocks */
 102   int pc;  /* next position to code (equivalent to `ncode') */
 103   int lasttarget;   /* 'label' of last 'jump label' */
 104   int jpc;  /* list of pending jumps to `pc' */
 105   int nk;  /* number of elements in `k' */
 106   int np;  /* number of elements in `p' */
 107   int firstlocal;  /* index of first local var (in Dyndata array) */
 108   short nlocvars;  /* number of elements in 'f->locvars' */
 109   lu_byte nactvar;  /* number of active local variables */
 110   lu_byte nups;  /* number of upvalues */
 111   lu_byte freereg;  /* first free register */
 112 } FuncState;
 113
 114
 115 LUAI_FUNC Closure *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff,
 116                                 Dyndata *dyd, const char *name, int firstchar);
 117
 118
 119 #endif