lparser.h
(5.4.6)
/*
** $Id: lparser.h $
** Lua Parser
** See Copyright Notice in lua.h
*/
#ifndef lparser_h
#define lparser_h
#include "llimits.h"
#include "lobject.h"
#include "lzio.h"
/*
** Expression and variable descriptor.
** Code generation for variables and expressions can be delayed to allow
** optimizations; An 'expdesc' structure describes a potentially-delayed
** variable/expression. It has a description of its "main" value plus a
** list of conditional jumps that can also produce its value (generated
** by short-circuit operators 'and'/'or').
*/
/* kinds of variables/expressions */
typedef enum {
VVOID, /* when 'expdesc' describes the last expression of a list,
this kind means an empty list (so, no expression) */
VNIL, /* constant nil */
VTRUE, /* constant true */
VFALSE, /* constant false */
VK, /* constant in 'k'; info = index of constant in 'k' */
VKFLT, /* floating constant; nval = numerical float value */
VKINT, /* integer constant; ival = numerical integer value */
VKSTR, /* string constant; strval = TString address;
(string is fixed by the lexer) */
VNONRELOC, /* expression has its value in a fixed register;
info = result register */
VLOCAL, /* local variable; var.ridx = register index;
var.vidx = relative index in 'actvar.arr' */
VUPVAL, /* upvalue variable; info = index of upvalue in 'upvalues' */
VCONST, /* compile-time <const> variable;
info = absolute index in 'actvar.arr' */
VINDEXED, /* indexed variable;
ind.t = table register;
ind.idx = key's R index */
VINDEXUP, /* indexed upvalue;
ind.t = table upvalue;
ind.idx = key's K index */
VINDEXI, /* indexed variable with constant integer;
ind.t = table register;
ind.idx = key's value */
VINDEXSTR, /* indexed variable with literal string;
ind.t = table register;
ind.idx = key's K index */
VJMP, /* expression is a test/comparison;
info = pc of corresponding jump instruction */
VRELOC, /* expression can put result in any register;
info = instruction pc */
VCALL, /* expression is a function call; info = instruction pc */
VVARARG /* vararg expression; info = instruction pc */
} expkind;
#define vkisvar(k) (VLOCAL <= (k) && (k) <= VINDEXSTR)
#define vkisindexed(k) (VINDEXED <= (k) && (k) <= VINDEXSTR)
typedef struct expdesc {
expkind k;
union {
lua_Integer ival; /* for VKINT */
lua_Number nval; /* for VKFLT */
TString *strval; /* for VKSTR */
int info; /* for generic use */
struct { /* for indexed variables */
short idx; /* index (R or "long" K) */
lu_byte t; /* table (register or upvalue) */
} ind;
struct { /* for local variables */
lu_byte ridx; /* register holding the variable */
unsigned short vidx; /* compiler index (in 'actvar.arr') */
} var;
} u;
int t; /* patch list of 'exit when true' */
int f; /* patch list of 'exit when false' */
} expdesc;
/* kinds of variables */
#define VDKREG 0 /* regular */
#define RDKCONST 1 /* constant */
#define RDKTOCLOSE 2 /* to-be-closed */
#define RDKCTC 3 /* compile-time constant */
/* description of an active local variable */
typedef union Vardesc {
struct {
TValuefields; /* constant value (if it is a compile-time constant) */
lu_byte kind;
lu_byte ridx; /* register holding the variable */
short pidx; /* index of the variable in the Proto's 'locvars' array */
TString *name; /* variable name */
} vd;
TValue k; /* constant value (if any) */
} Vardesc;
/* description of pending goto statements and label statements */
typedef struct Labeldesc {
TString *name; /* label identifier */
int pc; /* position in code */
int line; /* line where it appeared */
lu_byte nactvar; /* number of active variables in that position */
lu_byte close; /* goto that escapes upvalues */
} Labeldesc;
/* list of labels or gotos */
typedef struct Labellist {
Labeldesc *arr; /* array */
int n; /* number of entries in use */
int size; /* array size */
} Labellist;
/* dynamic structures used by the parser */
typedef struct Dyndata {
struct { /* list of all active local variables */
Vardesc *arr;
int n;
int size;
} actvar;
Labellist gt; /* list of pending gotos */
Labellist label; /* list of active labels */
} Dyndata;
/* control of blocks */
struct BlockCnt; /* defined in lparser.c */
/* state needed to generate code for a given function */
typedef struct FuncState {
Proto *f; /* current function header */
struct FuncState *prev; /* enclosing function */
struct LexState *ls; /* lexical state */
struct BlockCnt *bl; /* chain of current blocks */
int pc; /* next position to code (equivalent to 'ncode') */
int lasttarget; /* 'label' of last 'jump label' */
int previousline; /* last line that was saved in 'lineinfo' */
int nk; /* number of elements in 'k' */
int np; /* number of elements in 'p' */
int nabslineinfo; /* number of elements in 'abslineinfo' */
int firstlocal; /* index of first local var (in Dyndata array) */
int firstlabel; /* index of first label (in 'dyd->label->arr') */
short ndebugvars; /* number of elements in 'f->locvars' */
lu_byte nactvar; /* number of active local variables */
lu_byte nups; /* number of upvalues */
lu_byte freereg; /* first free register */
lu_byte iwthabs; /* instructions issued since last absolute line info */
lu_byte needclose; /* function needs to close upvalues when returning */
} FuncState;
LUAI_FUNC int luaY_nvarstack (FuncState *fs);
LUAI_FUNC LClosure *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff,
Dyndata *dyd, const char *name, int firstchar);
#endif