Lua5.1代码阅读（四）：lparser.h/lparser.c
（未完成，待修改）
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一、概述
lparser.h/lparser.c是Lua的语法分析器。
用于分析Lua脚本的语法以及把上下文信息传递给代码生成器，
完成文本代码到二进制代码的转换，以及语法检查。
在线版：
http://www.lua.org/source/5.1/lparser.h.html
http://www.lua.org/source/5.1/lparser.c.html
lparser内部主要函数的引用图如下：（只含部分）
在Lua参考手册（LRM）中描述了Lua的基本语法，见
http://www.lua.org/manual/5.1/manual.html#8
可以画出的关系图大概是这样子：
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二、枚举值
1. typedef enum {
?VVOID,/* 无值 */
?VNIL,
?VTRUE,
?VFALSE,
?VK,/* info = k内常量的索引 */
?VKNUM,/* nval = 数值 */
?VLOCAL,/* info = 局部寄存器 */
?VUPVAL, ? /* info = upvalues内的上值索引 */
?VGLOBAL,/* info = 表索引; aux = k内全局名称的索引 */
?VINDEXED,/* info = 表寄存器; aux = 索引寄存器（或k） */
?VJMP,/* info = 指令pc */
?VRELOCABLE,/* info = 指令pc */
?VNONRELOC,/* info = 结果寄存器 */
?VCALL,/* info = 指令pc */
?VVARARG/* info = 指令pc */
} expkind;
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三、结构体、联合体
1. typedef struct expdesc {
?expkind k;
?union {
struct { int info, aux; } s;
lua_Number nval;
?} u;
?int t; ?/* 真时退出的补丁列表 */
?int f; ?/* 假时退出的补丁列表 */
} expdesc;
2. typedef struct upvaldesc {
?lu_byte k;
?lu_byte info;
} upvaldesc;
3. typedef struct FuncState {
?Proto *f; ?/* 当前函数头 */
?Table *h; ?/* 用来查找（或重用）k内元素的表*/
?struct FuncState *prev; ?/* 闭合函数 */
?struct LexState *ls; ?/* 词法状态 */
?struct lua_State *L; ?/* Lua状态的复制 */
?struct BlockCnt *bl; ?/* 当前块链 */
?int pc; ?/* 代码的下一个位置（等价于ncode） */
?int lasttarget; ? /* 上一次jump target的pc */
?int jpc; ?/* 即将跳转的pc列表 */
?int freereg; ?/* 第一个空闲的寄存器 */
?int nk; ?/* k内的元素个数 */
?int np; ?/* p内的元素个数 */
?short nlocvars; ?/* locvars内的元素个数 */
?lu_byte nactvar; ?/*激活的局部变量的个数 */
?upvaldesc upvalues[LUAI_MAXUPVALUES]; ?/* 上值 */
?unsigned short actvar[LUAI_MAXVARS]; ?/* 已声明变量的堆栈 */
} FuncState;
4. typedef struct BlockCnt {
?struct BlockCnt *previous; ?/* 链 */
?int breaklist; ?/* 跳出此循环的列表 */
?lu_byte nactvar; ?/* 在可跳出结构外的激活局部变量 */
?lu_byte upval; ?/* 如果块的一些变量为上值的话为真 */
?lu_byte isbreakable; ?/* 如果块为循环的话为真 */
} BlockCnt;
5. struct ConsControl {
?expdesc v; ?/* 上一次读入的列表项 */
?expdesc *t; ?/* 表描述符 */
?int nh; ?/* record元素的总数 */
?int na; ?/* 数组元素的总数 */
?int tostore; ?/* 将要被存储的数组元素的个数 */
};
6. static const struct {
?lu_byte left; ?/* 每个二元操作符的左优先级 */
?lu_byte right; /* 右优先级 */
} priority[] = { ?/* ORDER OPR */
? {6, 6}, {6, 6}, {7, 7}, {7, 7}, {7, 7}, ?/* `+' `-' `/' `%' */
? {10, 9}, {5, 4}, ? ? ? ? ? ? ? ? /* 乘幂和拼接 (右结合) */
? {3, 3}, {3, 3}, ? ? ? ? ? ? ? ? ?/* 相等和不等 */
? {3, 3}, {3, 3}, {3, 3}, {3, 3}, ?/* 排序 */
? {2, 2}, {1, 1} ? ? ? ? ? ? ? ? ? /* 逻辑（与或） */
};
7. struct LHS_assign {
?struct LHS_assign *prev;
?expdesc v; ?/* 变量（全局，局部，上值，或索引） */
};
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四、宏
1. #define lparser_c
2. #define LUA_CORE
3. #define hasmultret(k)((k) == VCALL || (k) == VVARARG)
4. #define getlocvar(fs, i)((fs)->f->locvars[(fs)->actvar[i]])
5. #define luaY_checklimit(fs,v,l,m)if ((v)>(l)) errorlimit(fs,l,m)
6. #define check_condition(ls,c,msg){ if (!(c)) luaX_syntaxerror(ls, msg); }
7. #define new_localvarliteral(ls,v,n) \
new_localvar(ls, luaX_newstring(ls, "" v, (sizeof(v)/sizeof(char))-1), n)
8. #define leavelevel(ls)((ls)->L->nCcalls--)
9. #define UNARY_PRIORITY8 ?/* 一元操作符的优先级 */
五、公共全局函数
1. Proto *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff, const char *name) {
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六、私有静态函数
1. static void anchor_token (LexState *ls) {
2. static void error_expected (LexState *ls, int token) {
3. static void errorlimit (FuncState *fs, int limit, const char *what) {
4. static int testnext (LexState *ls, int c) {
5. static void check (LexState *ls, int c) {
6. static void checknext (LexState *ls, int c) {
7. static void check_match (LexState *ls, int what, int who, int where) {
8. static TString *str_checkname (LexState *ls) {
9. static void init_exp (expdesc *e, expkind k, int i) {
10. static void codestring (LexState *ls, expdesc *e, TString *s) {
11. static void checkname(LexState *ls, expdesc *e) {
12. static int registerlocalvar (LexState *ls, TString *varname) {
13. static void new_localvar (LexState *ls, TString *name, int n) {
14. static void adjustlocalvars (LexState *ls, int nvars) {
15. static void removevars (LexState *ls, int tolevel) {
16. static int indexupvalue (FuncState *fs, TString *name, expdesc *v) {
17. static int searchvar (FuncState *fs, TString *n) {
18. static void markupval (FuncState *fs, int level) {
19. static int singlevaraux (FuncState *fs, TString *n, expdesc *var, int base) {
20. static void singlevar (LexState *ls, expdesc *var) {
21. static void adjust_assign (LexState *ls, int nvars, int nexps, expdesc *e) {
22. static void enterlevel (LexState *ls) {
23. static void enterblock (FuncState *fs, BlockCnt *bl, lu_byte isbreakable) {
24. static void leaveblock (FuncState *fs) {
25. static void pushclosure (LexState *ls, FuncState *func, expdesc *v) {
26. static void open_func (LexState *ls, FuncState *fs) {
27. static void close_func (LexState *ls) {
28. static void field (LexState *ls, expdesc *v) {
29. static void yindex (LexState *ls, expdesc *v) {
30. static void recfield (LexState *ls, struct ConsControl *cc) {
31. static void closelistfield (FuncState *fs, struct ConsControl *cc) {
32. static void lastlistfield (FuncState *fs, struct ConsControl *cc) {
33. static void listfield (LexState *ls, struct ConsControl *cc) {
34. static void constructor (LexState *ls, expdesc *t) {
35. static void parlist (LexState *ls) {
36. static void body (LexState *ls, expdesc *e, int needself, int line) {
37. static int explist1 (LexState *ls, expdesc *v) {
38. static void funcargs (LexState *ls, expdesc *f) {
39. static void prefixexp (LexState *ls, expdesc *v) {
40. static void primaryexp (LexState *ls, expdesc *v) {
41. static void simpleexp (LexState *ls, expdesc *v) {
42. static UnOpr getunopr (int op) {
43. static BinOpr getbinopr (int op) {
44. static BinOpr subexpr (LexState *ls, expdesc *v, unsigned int limit) {
45. static void expr (LexState *ls, expdesc *v) {
46. static int block_follow (int token) {
47. static void block (LexState *ls) {
48. static void check_conflict (LexState *ls, struct LHS_assign *lh, expdesc *v) {
49. static void assignment (LexState *ls, struct LHS_assign *lh, int nvars) {
50. static int cond (LexState *ls) {
51. static void breakstat (LexState *ls) {
52. static void whilestat (LexState *ls, int line) {
53. static void repeatstat (LexState *ls, int line) {
54. static int exp1 (LexState *ls) {
55. static void forbody (LexState *ls, int base, int line, int nvars, int isnum) {
56. static void fornum (LexState *ls, TString *varname, int line) {
57. static void forlist (LexState *ls, TString *indexname) {
58. static void forstat (LexState *ls, int line) {
59. static int test_then_block (LexState *ls) {
60. static void ifstat (LexState *ls, int line) {
61. static void localfunc (LexState *ls) {
62. static void localstat (LexState *ls) {
63. static int funcname (LexState *ls, expdesc *v) {
64. static void funcstat (LexState *ls, int line) {
65. static void exprstat (LexState *ls) {
66. static void retstat (LexState *ls) {
67. static int statement (LexState *ls) {
68. static void chunk (LexState *ls) {
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七、值得观察的代码
1. luaY_parser
Lua语法分析器的入口
2. chunk/block/expr/subexpr/constructor/explist1
Lua语法中几个重要元素
（未完成，待修改）
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