client/deps/liblua/lparser.h

   1 /*
   2 ** $Id: lparser.h $
   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 of 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; ival = numerical integer value */
  34     VKSTR,  /* string constant; strval = TString address;
  35              (string is fixed by the lexer) */
  36     VNONRELOC,  /* expression has its value in a fixed register;
  37                  info = result register */
  38     VLOCAL,  /* local variable; var.ridx = register index;
  39               var.vidx = relative index in 'actvar.arr'  */
  40     VUPVAL,  /* upvalue variable; info = index of upvalue in 'upvalues' */
  41     VCONST,  /* compile-time <const> variable;
  42               info = absolute index in 'actvar.arr'  */
  43     VINDEXED,  /* indexed variable;
  44                 ind.t = table register;
  45                 ind.idx = key's R index */
  46     VINDEXUP,  /* indexed upvalue;
  47                 ind.t = table upvalue;
  48                 ind.idx = key's K index */
  49     VINDEXI, /* indexed variable with constant integer;
  50                 ind.t = table register;
  51                 ind.idx = key's value */
  52     VINDEXSTR, /* indexed variable with literal string;
  53                 ind.t = table register;
  54                 ind.idx = key's K index */
  55     VJMP,  /* expression is a test/comparison;
  56             info = pc of corresponding jump instruction */
  57     VRELOC,  /* expression can put result in any register;
  58               info = instruction pc */
  59     VCALL,  /* expression is a function call; info = instruction pc */
  60     VVARARG  /* vararg expression; info = instruction pc */
  61 } expkind;
  62
  63
  64 #define vkisvar(k)      (VLOCAL <= (k) && (k) <= VINDEXSTR)
  65 #define vkisindexed(k)  (VINDEXED <= (k) && (k) <= VINDEXSTR)
  66
  67
  68 typedef struct expdesc {
  69     expkind k;
  70     union {
  71         lua_Integer ival;    /* for VKINT */
  72         lua_Number nval;  /* for VKFLT */
  73         TString *strval;  /* for VKSTR */
  74         int info;  /* for generic use */
  75         struct {  /* for indexed variables */
  76             short idx;  /* index (R or "long" K) */
  77             lu_byte t;  /* table (register or upvalue) */
  78         } ind;
  79         struct {  /* for local variables */
  80             lu_byte ridx;  /* register holding the variable */
  81             unsigned short vidx;  /* compiler index (in 'actvar.arr')  */
  82         } var;
  83     } u;
  84     int t;  /* patch list of 'exit when true' */
  85     int f;  /* patch list of 'exit when false' */
  86 } expdesc;
  87
  88
  89 /* kinds of variables */
  90 #define VDKREG          0   /* regular */
  91 #define RDKCONST        1   /* constant */
  92 #define RDKTOCLOSE      2   /* to-be-closed */
  93 #define RDKCTC          3   /* compile-time constant */
  94
  95 /* description of an active local variable */
  96 typedef union Vardesc {
  97     struct {
  98         TValuefields;  /* constant value (if it is a compile-time constant) */
  99         lu_byte kind;
 100         lu_byte ridx;  /* register holding the variable */
 101         short pidx;  /* index of the variable in the Proto's 'locvars' array */
 102         TString *name;  /* variable name */
 103     } vd;
 104     TValue k;  /* constant value (if any) */
 105 } Vardesc;
 106
 107
 108
 109 /* description of pending goto statements and label statements */
 110 typedef struct Labeldesc {
 111     TString *name;  /* label identifier */
 112     int pc;  /* position in code */
 113     int line;  /* line where it appeared */
 114     lu_byte nactvar;  /* number of active variables in that position */
 115     lu_byte close;  /* goto that escapes upvalues */
 116 } Labeldesc;
 117
 118
 119 /* list of labels or gotos */
 120 typedef struct Labellist {
 121     Labeldesc *arr;  /* array */
 122     int n;  /* number of entries in use */
 123     int size;  /* array size */
 124 } Labellist;
 125
 126
 127 /* dynamic structures used by the parser */
 128 typedef struct Dyndata {
 129     struct {  /* list of all active local variables */
 130         Vardesc *arr;
 131         int n;
 132         int size;
 133     } actvar;
 134     Labellist gt;  /* list of pending gotos */
 135     Labellist label;   /* list of active labels */
 136 } Dyndata;
 137
 138
 139 /* control of blocks */
 140 struct BlockCnt;  /* defined in lparser.c */
 141
 142
 143 /* state needed to generate code for a given function */
 144 typedef struct FuncState {
 145     Proto *f;  /* current function header */
 146     struct FuncState *prev;  /* enclosing function */
 147     struct LexState *ls;  /* lexical state */
 148     struct BlockCnt *bl;  /* chain of current blocks */
 149     int pc;  /* next position to code (equivalent to 'ncode') */
 150     int lasttarget;   /* 'label' of last 'jump label' */
 151     int previousline;  /* last line that was saved in 'lineinfo' */
 152     int nk;  /* number of elements in 'k' */
 153     int np;  /* number of elements in 'p' */
 154     int nabslineinfo;  /* number of elements in 'abslineinfo' */
 155     int firstlocal;  /* index of first local var (in Dyndata array) */
 156     int firstlabel;  /* index of first label (in 'dyd->label->arr') */
 157     short ndebugvars;  /* number of elements in 'f->locvars' */
 158     lu_byte nactvar;  /* number of active local variables */
 159     lu_byte nups;  /* number of upvalues */
 160     lu_byte freereg;  /* first free register */
 161     lu_byte iwthabs;  /* instructions issued since last absolute line info */
 162     lu_byte needclose;  /* function needs to close upvalues when returning */
 163 } FuncState;
 164
 165
 166 LUAI_FUNC int luaY_nvarstack(FuncState *fs);
 167 LUAI_FUNC LClosure *luaY_parser(lua_State *L, ZIO *z, Mbuffer *buff,
 168                                 Dyndata *dyd, const char *name, int firstchar);
 169
 170
 171 #endif