?login_element?

Subversion Repositories NedoOS

Rev

Blame | Last modification | View Log | Download

  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
  172.