Lucy:
Lucy is a powerful and lightweight Lua wapper for C language, which has three design goals:
1) Hide the lua_State* type virtual stack, and hide the official C API, which is    based on the virtual stack.
2) Use Lua codes in C more plain and more natually.
3) Regard Lua reference type, i.e. table and function as first-class type in C. Actually, it is a supplement for 2).

Example:
Here is a period of Lua code in Lua file "a.lua":

function Loc(x, y)
    return function() return x, y end
end

function Area(loc)
    local x, y = loc()
    return x * y
end

Given the value of x and y, How to call the function Area?
Using Lucy, the thing is simple:

int Area(int x, int y)
{
    lucy_File file = lucy_CreateFile();
    lucy_OpenFile(&file, "a.lua");

    lucy_Data Loc = lucy_GetData(&file, "Loc");
    lucy_Data nx = lucy_Num(x);
    lucy_Data ny = lucy_Num(y);
    lucy_Data loc = lucy_Call(&Loc, 1, 2, &nx, &ny).datas_[0];
    
    lucy_Data Area = lucy_GetData(&file, "Area");
    lucy_Data area = lucy_Call(&Area, 1, 1, &loc).datas_[0];
    
    lucy_CloseFile(&file);
    return area;
}

Interfaces:
file:
lucy_File lucy_CreateFile();
void lucy_OpenFile(const lucy_File *lua_file, const char *name);
void lucy_CloseFile(const lucy_File *lua_file);
lucy_Data lucy_GetData(const lucy_File *lua_file,
                       const char *name);

Variants creaating:
lucy_Data lucy_Num(double num);
lucy_Data lucy_Bool(bool boolean);
lucy_Data lucy_Str(const char *str);
lucy_Data lucy_Nil();

Function:
lucy_List lucy_CallWithList(const lucy_Data *func, int rc,
                            const lucy_List *args);
lucy_List lucy_Call(const lucy_Data *func, int rc, int argsc, ...);
lucy_List lucy_GetList(size_t len, ...);

Table:
lucy_Data lucy_TblData(const lucy_Data *tbl, const char *key);
lucy_Data lucy_ArrData(const lucy_Data *tbl, int index);
int lucy_ArrLen(const lucy_Data *tbl);