dependencies/lua-5.3/src/lparser.h

   1 /*
   2 ** $Id: lparser.h,v 1.76 2015/12/30 18:16:13 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 and variable descriptor.
  17 ** Code generation for variables and expressions can be delayed to allow
  18 ** optimizations; An 'expdesc' structure describes a potentially-delayed
  19 ** variable/expression. It has a description of its "main" value plus a
  20 ** list of conditional jumps that can also produce its value (generated
  21 ** by short-circuit operators 'and'/'or').
  22 */
  23
  24 /* kinds of variables/expressions */
  25 typedef enum {
  26   VVOID,  /* when 'expdesc' describes the last expression a list,
  27              this kind means an empty list (so, no expression) */
  28   VNIL,  /* constant nil */
  29   VTRUE,  /* constant true */
  30   VFALSE,  /* constant false */
  31   VK,  /* constant in 'k'; info = index of constant in 'k' */
  32   VKFLT,  /* floating constant; nval = numerical float value */
  33   VKINT,  /* integer constant; nval = numerical integer value */
  34   VNONRELOC,  /* expression has its value in a fixed register;
  35                  info = result register */
  36   VLOCAL,  /* local variable; info = local register */
  37   VUPVAL,  /* upvalue variable; info = index of upvalue in 'upvalues' */
  38   VINDEXED,  /* indexed variable;
  39                 ind.vt = whether 't' is register or upvalue;
  40                 ind.t = table register or upvalue;
  41                 ind.idx = key's R/K index */
  42   VJMP,  /* expression is a test/comparison;
  43             info = pc of corresponding jump instruction */
  44   VRELOCABLE,  /* expression can put result in any register;
  45                   info = instruction pc */
  46   VCALL,  /* expression is a function call; info = instruction pc */
  47   VVARARG  /* vararg expression; info = instruction pc */
  48 } expkind;
  49
  50
  51 #define vkisvar(k)      (VLOCAL <= (k) && (k) <= VINDEXED)
  52 #define vkisinreg(k)    ((k) == VNONRELOC || (k) == VLOCAL)
  53
  54 typedef struct expdesc {
  55   expkind k;
  56   union {
  57     lua_Integer ival;    /* for VKINT */
  58     lua_Number nval;  /* for VKFLT */
  59     int info;  /* for generic use */
  60     struct {  /* for indexed variables (VINDEXED) */
  61       short idx;  /* index (R/K) */
  62       lu_byte t;  /* table (register or upvalue) */
  63       lu_byte vt;  /* whether 't' is register (VLOCAL) or upvalue (VUPVAL) */
  64     } ind;
  65   } u;
  66   int t;  /* patch list of 'exit when true' */
  67   int f;  /* patch list of 'exit when false' */
  68 } expdesc;
  69
  70
  71 /* description of active local variable */
  72 typedef struct Vardesc {
  73   short idx;  /* variable index in stack */
  74 } Vardesc;
  75
  76
  77 /* description of pending goto statements and label statements */
  78 typedef struct Labeldesc {
  79   TString *name;  /* label identifier */
  80   int pc;  /* position in code */
  81   int line;  /* line where it appeared */
  82   lu_byte nactvar;  /* local level where it appears in current block */
  83 } Labeldesc;
  84
  85
  86 /* list of labels or gotos */
  87 typedef struct Labellist {
  88   Labeldesc *arr;  /* array */
  89   int n;  /* number of entries in use */
  90   int size;  /* array size */
  91 } Labellist;
  92
  93
  94 /* dynamic structures used by the parser */
  95 typedef struct Dyndata {
  96   struct {  /* list of active local variables */
  97     Vardesc *arr;
  98     int n;
  99     int size;
 100   } actvar;
 101   Labellist gt;  /* list of pending gotos */
 102   Labellist label;   /* list of active labels */
 103 } Dyndata;
 104
 105
 106 /* control of blocks */
 107 struct BlockCnt;  /* defined in lparser.c */
 108
 109
 110 /* state needed to generate code for a given function */
 111 typedef struct FuncState {
 112   Proto *f;  /* current function header */
 113   struct FuncState *prev;  /* enclosing function */
 114   struct LexState *ls;  /* lexical state */
 115   struct BlockCnt *bl;  /* chain of current blocks */
 116   int pc;  /* next position to code (equivalent to 'ncode') */
 117   int lasttarget;   /* 'label' of last 'jump label' */
 118   int jpc;  /* list of pending jumps to 'pc' */
 119   int nk;  /* number of elements in 'k' */
 120   int np;  /* number of elements in 'p' */
 121   int firstlocal;  /* index of first local var (in Dyndata array) */
 122   short nlocvars;  /* number of elements in 'f->locvars' */
 123   lu_byte nactvar;  /* number of active local variables */
 124   lu_byte nups;  /* number of upvalues */
 125   lu_byte freereg;  /* first free register */
 126 } FuncState;
 127
 128
 129 LUAI_FUNC LClosure *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff,
 130                                  Dyndata *dyd, const char *name, int firstchar);
 131
 132
 133 #endif