/*
** $Id: lparser.h,v 1.5 1999/11/22 13:12:07 roberto Exp roberto $
** LL(1) Parser and code generator for Lua
** See Copyright Notice in lua.h
*/

#ifndef lparser_h
#define lparser_h

#include "lobject.h"
#include "lopcodes.h"
#include "lzio.h"


/* maximum number of local variables */
#ifndef MAXLOCALS
#define MAXLOCALS 200  /* arbitrary limit (<=MAXARG_B) */
#endif


/* maximum number of upvalues */
#ifndef MAXUPVALUES
#define MAXUPVALUES 32  /* arbitrary limit (<=MAXARG_B) */
#endif


/* maximum number of variables in the left side of an assignment */
#ifndef MAXVARSLH
#define MAXVARSLH	100  /* arbitrary limit (<=MAXARG_B) */
#endif


/* maximum number of parameters in a function */
#ifndef MAXPARAMS
#define MAXPARAMS	100  /* arbitrary limit (<=MAXLOCALS) */
#endif


/* maximum stack size in a function */
#ifndef MAXSTACK
#define MAXSTACK	256  /* arbitrary limit (<=MAXARG_A) */
#endif


#if MAXLOCALS>MAXARG_U || MAXUPVALUES>MAXARG_B || MAXVARSLH>MAXARG_B || \
    MAXPARAMS>MAXLOCALS || MAXSTACK>MAXARG_A || LFIELDS_PER_FLUSH>MAXARG_B
#error invalid limits
#endif



/*
** Variable descriptor:
** must include an `exp' option because LL(1) cannot distinguish
** between variables, upvalues and function calls on first sight.
*/
typedef enum {
  VGLOBAL,  /* info is constant index of global name */
  VLOCAL,   /* info is stack index */
  VINDEXED, /* no info (table and index are on the stack) */
  VEXP      /* info is pc index of a call (or 0 if exp is closed) */
} varkind;

typedef struct vardesc {
  varkind k;
  int info;
} vardesc;


/* state needed to generate code for a given function */
typedef struct FuncState {
  TProtoFunc *f;  /* current function header */
  struct FuncState *prev;  /* enclosing function */
  int pc;  /* next position to code */
  int last_pc;  /* last instruction coded (for optimizations) */
  int stacksize;  /* number of values on activation register */
  int nlocalvar;  /* number of active local variables */
  int nupvalues;  /* number of upvalues */
  int nvars;  /* number of entries in f->locvars (-1 if no debug information) */
  int lastsetline;  /* line where last SETLINE was issued */
  vardesc upvalues[MAXUPVALUES];  /* upvalues */
  TaggedString *localvar[MAXLOCALS];  /* store local variable names */
} FuncState;


TProtoFunc *luaY_parser (lua_State *L, ZIO *z);


#endif