如何使用C API创建嵌套的Lua表 [英] How to create nested Lua tables using the C API
问题描述
我想创建一个表格
myTable = {
[0] = { ] = 4,[b] = 2},
[1] = {[a] = 13,[b] = 37}
}
$
我目前的方法是
lua_createtable(L,0,2);
int c = lua_gettop(L);
lua_prewstring(L,a);
lua_pushnumber(L,4);
lua_settable(L,c);
lua_pushstring(L,b);
lua_pushnumber(L,2);
lua_settable(L,c);
在循环中创建内表。之前,这个循环,我使用
lua_createtable(L,2,0);
int outertable = lua_gettop(L);
为2个数字位置创建外表。
但是如何将内部表保存到外部表?
解决方案嵌套表。基本上您缺少的是 lua_setfield
功能。
#include< stdio.h>
#includelua.h
#includelauxlib.h
#includelualib.h
int main()
{
int res;
lua_State * L = lua_open();
luaL_openlibs(L);
lua_newtable(L); / * bottom table * /
lua_newtable(L); / * upper table * /
lua_pushinteger(L,4);
lua_setfield(L,-2,four); / * T [four] = 4 * /
lua_setfield(L,-2,T); / * name上表字段T底部表* /
lua_setglobal(L,t); / *将底表设置为全局变量t * /
res = luaL_dostring(L,print(t.T.four == 4));
if(res)
{
printf(Error:%s\\\
,lua_tostring(L,-1));
}
return 0;
}
程序将打印 true
。
如果您需要数字索引,请继续使用 lua_settable
:
#include< stdio.h>
#includelua.h
#includelauxlib.h
#includelualib.h
int main()
{
int res;
lua_State * L = lua_open();
luaL_openlibs(L);
lua_newtable(L); / * bottom table * /
lua_newtable(L); / *上表* /
lua_pushinteger(L,0);
lua_pushinteger(L,4);
lua_settable(L,-3); / * uppertable [0] = 4; pops 0和4 * /
lua_pushinteger(L,0);
lua_insert(L,-2); / * swap uppertable和0 * /
lua_settable(L,-3); / * bottomtable [0] = uppertable * /
lua_setglobal(L,t); / * set bottom table as global variable t * /
res = luaL_dostring(L,print(t [0] [0] == 4));
if(res)
{
printf(Error:%s\\\
,lua_tostring(L,-1));
}
return 0;
}
而不是像我这样使用绝对索引0,你可能想使用 lua_objlen
生成索引。
I want to create a table like
myTable = {
[0] = { ["a"] = 4, ["b"] = 2 },
[1] = { ["a"] = 13, ["b"] = 37 }
}
using the C API?
My current approach is
lua_createtable(L, 0, 2);
int c = lua_gettop(L);
lua_pushstring(L, "a");
lua_pushnumber(L, 4);
lua_settable(L, c);
lua_pushstring(L, "b");
lua_pushnumber(L, 2);
lua_settable(L, c);
to create the inner tables in a loop. Before, this loop, I use
lua_createtable(L, 2, 0);
int outertable = lua_gettop(L);
to create the outer table for 2 numeric slots.
But how can I save the inner tables to the outer table?
解决方案 Here's a full and minimal program demonstrating how to nest tables. Basically what you are missing is the lua_setfield
function.
#include <stdio.h>
#include "lua.h"
#include "lauxlib.h"
#include "lualib.h"
int main()
{
int res;
lua_State *L = lua_open();
luaL_openlibs(L);
lua_newtable(L); /* bottom table */
lua_newtable(L); /* upper table */
lua_pushinteger(L, 4);
lua_setfield(L, -2, "four"); /* T[four] = 4 */
lua_setfield(L, -2, "T"); /* name upper table field T of bottom table */
lua_setglobal(L, "t"); /* set bottom table as global variable t */
res = luaL_dostring(L, "print(t.T.four == 4)");
if(res)
{
printf("Error: %s\n", lua_tostring(L, -1));
}
return 0;
}
The program will simply print true
.
If you need numeric indices, then you continue using lua_settable
:
#include <stdio.h>
#include "lua.h"
#include "lauxlib.h"
#include "lualib.h"
int main()
{
int res;
lua_State *L = lua_open();
luaL_openlibs(L);
lua_newtable(L); /* bottom table */
lua_newtable(L); /* upper table */
lua_pushinteger(L, 0);
lua_pushinteger(L, 4);
lua_settable(L, -3); /* uppertable[0] = 4; pops 0 and 4 */
lua_pushinteger(L, 0);
lua_insert(L, -2); /* swap uppertable and 0 */
lua_settable(L, -3); /* bottomtable[0] = uppertable */
lua_setglobal(L, "t"); /* set bottom table as global variable t */
res = luaL_dostring(L, "print(t[0][0] == 4)");
if(res)
{
printf("Error: %s\n", lua_tostring(L, -1));
}
return 0;
}
Rather than using absolute indices of 0 like I did, you might want to use lua_objlen
to generate the index.
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