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Member "memcached-1.6.15/vendor/lua/src/lparser.h" (1 Oct 2021, 5927 Bytes) of package /linux/www/memcached-1.6.15.tar.gz:


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    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