Lua 脚本 控制 XML配置 - 之Lua学习1 ( 多维嵌套表的 C API 交互）

初步想法利用luaExpat， 但是expat不友好支持DOM parser只支持SAX，所以转向xmlLib2.

利用schema xsd,验证，修改或增加配置，再进行保存xml, 以实现自动扫描安全证书内容，导出部分内容输出到配置文件

边学边写，边记录

-

lua的ipair与pair的区别

Lua nested table iteration:

lua:

tbl1 = {

{ a = "aa",b = "bb", c = "cc"},

{ d= "dd", e = "ee", f = "ff"},

}

tbl2 = {

{ aa = "aaa",bb = "bbb", cc = "ccc", gg = { g1 = "g1g1",g2 = "g2g2"},},

{ dd = "ddd", ee = "eee", ff = "fff"},

}

C: code snippet：　

lua_pushstring(L, "hello world1");

lua_pushstring(L, "hello world12");

lua_pushstring(L, "hello world123");

Lua_pushvalue(L, 1);

Lua_getglobal(L, "tbl1");

t1 = lua_gettop(L);

lua_getglobal(L, "tbl2");

T2 = lua_gettop(L);

table_dump(L, t1, 3)　　　　

table_dump(L, t2, 3);

- int lua_next (lua_State *L, int index); index， 表不需要在栈顶

- 多重表格的遍历： lua_next是 先弹出1个元素，压入2个元素key-value, lua_pushnil仅仅是为了配合这- pop(1) push(2), pop(1) 操作而做的“无用操作”.

- 多重表格，碰到子表时，先是子表本身的key,值value是 table, 然后再说lua_next子表的内部元素。

- 循环时注意栈的平衡


/* Print a Lua table. depth_limit is the limit on recursive printing of

subtables. */

static void table_dump (lua_State *L, int idx, int depth_limit)

{

idx = lua_absindex(L, idx);

assert(lua_type(L, idx) == LUA_TTABLE);

printf("{");

for (lua_pushnil(L);; /*lua_next(L, idx); lua_pop(L, 1)*/) //分开为了调试，利用lua_gettop(L)查看栈长度，需要刷新

{

if ( lua_next(L, idx) <=0 ) break;

value_dump(L, -2, depth_limit - 1);

printf(" = ");

value_dump(L, -1, depth_limit - 1);

printf(", ");

lua_pop(L, 1);

}

printf("}");

}

/* Print a Lua value. depth_limit controls the depth to which tables will be

printed recursively (0 for no recursion). */

void value_dump (lua_State *L, int idx, int depth_limit)

{

int t ;

idx = lua_absindex(L, idx);

t = lua_type(L, idx);

switch (t)

{

case LUA_TSTRING: /* strings */

printf("'%s'", lua_tostring(L, idx));

break;

case LUA_TBOOLEAN: /* booleans */

printf(lua_toboolean(L, idx) ? "true" : "false");

break;

case LUA_TNUMBER: /* numbers */

printf("%g", lua_tonumber(L, idx));

break;

case LUA_TTABLE:

if (depth_limit > 0)

table_dump(L, idx, depth_limit);

else

printf("table: %p", lua_topointer(L, idx));

break;

case LUA_TTHREAD:

case LUA_TFUNCTION:

case LUA_TUSERDATA:

case LUA_TLIGHTUSERDATA:

printf("%s: %p", lua_typename(L, t), lua_topointer(L, idx));

break;

default: /* other values */

printf("%s", lua_typename(L, t));

break;

}

}