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      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
    120