1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
|
#define SOL_ALL_SAFETIES_ON 1
#include <sol/sol.hpp>
#include <iostream>
int main(int, char**) {
sol::state lua;
lua.open_libraries(sol::lib::base);
// Environments can set on functions (scripts), userdata and
// threads let's look at functions
lua.script("f = function() return test end");
sol::function f = lua["f"];
sol::environment env_f(lua, sol::create);
env_f["test"] = 31;
bool env_f_set_success = sol::set_environment(env_f, f);
SOL_ASSERT(env_f_set_success);
// the function returns the value from the environment table
int result = f();
SOL_ASSERT(result == 31);
// You can also protect from variables
// being set without the 'local' specifier
lua.script("g = function() test = 5 end");
sol::function g = lua["g"];
sol::environment env_g(lua, sol::create);
bool env_g_set_success
= env_g.set_on(g); // same as set_environment
SOL_ASSERT(env_g_set_success);
g();
// the value can be retrieved from the env table
int test = env_g["test"];
SOL_ASSERT(test == 5);
// the global environment
// is not polluted at all, despite both functions being used
// and set
sol::object global_test = lua["test"];
SOL_ASSERT(!global_test.valid());
// You can retrieve environments in C++
// and check the environment of functions
// gotten from Lua
// get the environment from any sol::reference-styled type,
// including sol::object, sol::function, sol::table,
// sol::userdata ...
lua.set_function("check_f_env",
// capture necessary variable in C++ lambda
[&env_f](sol::object target) {
// pull out the environment from func using
// sol::env_key constructor
sol::environment target_env(sol::env_key, target);
int test_env_f = env_f["test"];
int test_target_env = target_env["test"];
// the environment for f the one gotten from
// `target` are the same
SOL_ASSERT(test_env_f == test_target_env);
SOL_ASSERT(test_env_f == 31);
SOL_ASSERT(env_f == target_env);
});
lua.set_function(
"check_g_env", [&env_g](sol::function target) {
// equivalent:
sol::environment target_env
= sol::get_environment(target);
int test_env_g = env_g["test"];
int test_target_env = target_env["test"];
SOL_ASSERT(test_env_g == test_target_env);
SOL_ASSERT(test_env_g == 5);
SOL_ASSERT(env_g == target_env);
});
lua.script("check_f_env(f)");
lua.script("check_g_env(g)");
return 0;
}
|
