1 /*
2 ** $Id: lparser.h,v 1.70.1.1 2013/04/12 18:48:47 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 
19 typedef 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 
40 typedef 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 */
57 typedef struct Vardesc {
58   short idx;  /* variable index in stack */
59 } Vardesc;
60 
61 
62 /* description of pending goto statements and label statements */
63 typedef 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 */
72 typedef 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 */
80 typedef 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 */
92 struct BlockCnt;  /* defined in lparser.c */
93 
94 
95 /* state needed to generate code for a given function */
96 typedef 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 
115 LUAI_FUNC Closure *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff,
116                                 Dyndata *dyd, const char *name, int firstchar);
117 
118 
119 #endif
120