1/*
2** $Id: lparser.h,v 1.76.1.1 2017/04/19 17:20:42 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 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 */
25typedef enum {
26 VVOID, /* when 'expdesc' describes the last expression 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; nval = numerical integer value */
34 VNONRELOC, /* expression has its value in a fixed register;
35 info = result register */
36 VLOCAL, /* local variable; info = local register */
37 VUPVAL, /* upvalue variable; info = index of upvalue in 'upvalues' */
38 VINDEXED, /* indexed variable;
39 ind.vt = whether 't' is register or upvalue;
40 ind.t = table register or upvalue;
41 ind.idx = key's R/K index */
42 VJMP, /* expression is a test/comparison;
43 info = pc of corresponding jump instruction */
44 VRELOCABLE, /* expression can put result in any register;
45 info = instruction pc */
46 VCALL, /* expression is a function call; info = instruction pc */
47 VVARARG /* vararg expression; info = instruction pc */
48} expkind;
49
50
51#define vkisvar(k) (VLOCAL <= (k) && (k) <= VINDEXED)
52#define vkisinreg(k) ((k) == VNONRELOC || (k) == VLOCAL)
53
54typedef struct expdesc {
55 expkind k;
56 union {
57 lua_Integer ival; /* for VKINT */
58 lua_Number nval; /* for VKFLT */
59 int info; /* for generic use */
60 struct { /* for indexed variables (VINDEXED) */
61 short idx; /* index (R/K) */
62 lu_byte t; /* table (register or upvalue) */
63 lu_byte vt; /* whether 't' is register (VLOCAL) or upvalue (VUPVAL) */
64 } ind;
65 } u;
66 int t; /* patch list of 'exit when true' */
67 int f; /* patch list of 'exit when false' */
68} expdesc;
69
70
71/* description of active local variable */
72typedef struct Vardesc {
73 short idx; /* variable index in stack */
74} Vardesc;
75
76
77/* description of pending goto statements and label statements */
78typedef struct Labeldesc {
79 TString *name; /* label identifier */
80 int pc; /* position in code */
81 int line; /* line where it appeared */
82 lu_byte nactvar; /* local level where it appears in current block */
83} Labeldesc;
84
85
86/* list of labels or gotos */
87typedef struct Labellist {
88 Labeldesc *arr; /* array */
89 int n; /* number of entries in use */
90 int size; /* array size */
91} Labellist;
92
93
94/* dynamic structures used by the parser */
95typedef struct Dyndata {
96 struct { /* list of active local variables */
97 Vardesc *arr;
98 int n;
99 int size;
100 } actvar;
101 Labellist gt; /* list of pending gotos */
102 Labellist label; /* list of active labels */
103} Dyndata;
104
105
106/* control of blocks */
107struct BlockCnt; /* defined in lparser.c */
108
109
110/* state needed to generate code for a given function */
111typedef struct FuncState {
112 Proto *f; /* current function header */
113 struct FuncState *prev; /* enclosing function */
114 struct LexState *ls; /* lexical state */
115 struct BlockCnt *bl; /* chain of current blocks */
116 int pc; /* next position to code (equivalent to 'ncode') */
117 int lasttarget; /* 'label' of last 'jump label' */
118 int jpc; /* list of pending jumps to 'pc' */
119 int nk; /* number of elements in 'k' */
120 int np; /* number of elements in 'p' */
121 int firstlocal; /* index of first local var (in Dyndata array) */
122 short nlocvars; /* number of elements in 'f->locvars' */
123 lu_byte nactvar; /* number of active local variables */
124 lu_byte nups; /* number of upvalues */
125 lu_byte freereg; /* first free register */
126} FuncState;
127
128
129LUAI_FUNC LClosure *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff,
130 Dyndata *dyd, const char *name, int firstchar);
131
132
133#endif
134