1/*
2** $Id: lparser.h,v 1.70 2012/05/08 13:53:33 roberto Exp $
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 descriptor
17*/
18
19typedef enum {
20  VVOID,	/* no value */
21  VNIL,
22  VTRUE,
23  VFALSE,
24  VK,		/* info = index of constant in `k' */
25  VKNUM,	/* nval = numerical value */
26  VNONRELOC,	/* info = result register */
27  VLOCAL,	/* info = local register */
28  VUPVAL,       /* info = index of upvalue in 'upvalues' */
29  VINDEXED,	/* t = table register/upvalue; idx = index R/K */
30  VJMP,		/* info = instruction pc */
31  VRELOCABLE,	/* info = instruction pc */
32  VCALL,	/* info = instruction pc */
33  VVARARG	/* info = instruction pc */
34} expkind;
35
36
37#define vkisvar(k)	(VLOCAL <= (k) && (k) <= VINDEXED)
38#define vkisinreg(k)	((k) == VNONRELOC || (k) == VLOCAL)
39
40typedef struct expdesc {
41  expkind k;
42  union {
43    struct {  /* for indexed variables (VINDEXED) */
44      short idx;  /* index (R/K) */
45      lu_byte t;  /* table (register or upvalue) */
46      lu_byte vt;  /* whether 't' is register (VLOCAL) or upvalue (VUPVAL) */
47    } ind;
48    int info;  /* for generic use */
49    lua_Number nval;  /* for VKNUM */
50  } u;
51  int t;  /* patch list of `exit when true' */
52  int f;  /* patch list of `exit when false' */
53} expdesc;
54
55
56/* description of active local variable */
57typedef struct Vardesc {
58  short idx;  /* variable index in stack */
59} Vardesc;
60
61
62/* description of pending goto statements and label statements */
63typedef struct Labeldesc {
64  TString *name;  /* label identifier */
65  int pc;  /* position in code */
66  int line;  /* line where it appeared */
67  lu_byte nactvar;  /* local level where it appears in current block */
68} Labeldesc;
69
70
71/* list of labels or gotos */
72typedef struct Labellist {
73  Labeldesc *arr;  /* array */
74  int n;  /* number of entries in use */
75  int size;  /* array size */
76} Labellist;
77
78
79/* dynamic structures used by the parser */
80typedef struct Dyndata {
81  struct {  /* list of active local variables */
82    Vardesc *arr;
83    int n;
84    int size;
85  } actvar;
86  Labellist gt;  /* list of pending gotos */
87  Labellist label;   /* list of active labels */
88} Dyndata;
89
90
91/* control of blocks */
92struct BlockCnt;  /* defined in lparser.c */
93
94
95/* state needed to generate code for a given function */
96typedef struct FuncState {
97  Proto *f;  /* current function header */
98  Table *h;  /* table to find (and reuse) elements in `k' */
99  struct FuncState *prev;  /* enclosing function */
100  struct LexState *ls;  /* lexical state */
101  struct BlockCnt *bl;  /* chain of current blocks */
102  int pc;  /* next position to code (equivalent to `ncode') */
103  int lasttarget;   /* 'label' of last 'jump label' */
104  int jpc;  /* list of pending jumps to `pc' */
105  int nk;  /* number of elements in `k' */
106  int np;  /* number of elements in `p' */
107  int firstlocal;  /* index of first local var (in Dyndata array) */
108  short nlocvars;  /* number of elements in 'f->locvars' */
109  lu_byte nactvar;  /* number of active local variables */
110  lu_byte nups;  /* number of upvalues */
111  lu_byte freereg;  /* first free register */
112} FuncState;
113
114
115LUAI_FUNC Closure *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff,
116                                Dyndata *dyd, const char *name, int firstchar);
117
118
119#endif
120