mlua 0.7.4

High level bindings to Lua 5.4/5.3/5.2/5.1 (including LuaJIT) with async/await features and support of writing native Lua modules in Rust.
Documentation
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
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
#![cfg(feature = "serialize")]

use std::collections::HashMap;

use mlua::{
    DeserializeOptions, Error, Lua, LuaSerdeExt, Result as LuaResult, SerializeOptions, UserData,
    Value,
};
use serde::{Deserialize, Serialize};

#[test]
fn test_serialize() -> Result<(), Box<dyn std::error::Error>> {
    #[derive(Serialize)]
    struct MyUserData(i64, String);

    impl UserData for MyUserData {}

    let lua = Lua::new();
    let globals = lua.globals();

    let ud = lua.create_ser_userdata(MyUserData(123, "test userdata".into()))?;
    globals.set("ud", ud)?;
    globals.set("null", lua.null())?;

    let empty_array = lua.create_table()?;
    empty_array.set_metatable(Some(lua.array_metatable()));
    globals.set("empty_array", empty_array)?;

    let val = lua
        .load(
            r#"
        {
            _bool = true,
            _integer = 123,
            _number = 321.99,
            _string = "test string serialization",
            _table_arr = {nil, "value 1", nil, "value 2", {}},
            _table_map = {["table"] = "map", ["null"] = null},
            _bytes = "\240\040\140\040",
            _userdata = ud,
            _null = null,
            _empty_map = {},
            _empty_array = empty_array,
        }
    "#,
        )
        .eval::<Value>()?;

    let json = serde_json::json!({
        "_bool": true,
        "_integer": 123,
        "_number": 321.99,
        "_string": "test string serialization",
        "_table_arr": [null, "value 1", null, "value 2", {}],
        "_table_map": {"table": "map", "null": null},
        "_bytes": [240, 40, 140, 40],
        "_userdata": [123, "test userdata"],
        "_null": null,
        "_empty_map": {},
        "_empty_array": [],
    });

    assert_eq!(serde_json::to_value(&val)?, json);

    // Test to-from loop
    let val = lua.to_value(&json)?;
    let expected_json = lua.from_value::<serde_json::Value>(val)?;
    assert_eq!(expected_json, json);

    Ok(())
}

#[test]
fn test_serialize_in_scope() -> LuaResult<()> {
    #[derive(Serialize, Clone)]
    struct MyUserData(i64, String);

    impl UserData for MyUserData {}

    let lua = Lua::new();
    lua.scope(|scope| {
        let ud = scope.create_ser_userdata(MyUserData(-5, "test userdata".into()))?;
        assert_eq!(
            serde_json::to_value(&ud).unwrap(),
            serde_json::json!((-5, "test userdata"))
        );
        Ok(())
    })?;

    lua.scope(|scope| {
        let ud = scope.create_ser_userdata(MyUserData(-5, "test userdata".into()))?;
        lua.globals().set("ud", ud)
    })?;
    let val = lua.load("ud").eval::<Value>()?;
    match serde_json::to_value(&val) {
        Ok(v) => panic!("expected destructed error, got {}", v),
        Err(e) if e.to_string().contains("destructed") => {}
        Err(e) => panic!("expected destructed error, got {}", e),
    }

    struct MyUserDataRef<'a>(&'a ());

    impl<'a> UserData for MyUserDataRef<'a> {}

    lua.scope(|scope| {
        let ud = scope.create_nonstatic_userdata(MyUserDataRef(&()))?;
        match serde_json::to_value(&ud) {
            Ok(v) => panic!("expected serialization error, got {}", v),
            Err(serde_json::Error { .. }) => {}
        };
        Ok(())
    })?;

    Ok(())
}

#[test]
fn test_serialize_failure() -> Result<(), Box<dyn std::error::Error>> {
    #[derive(Serialize)]
    struct MyUserData(i64);

    impl UserData for MyUserData {}

    let lua = Lua::new();

    let ud = Value::UserData(lua.create_userdata(MyUserData(123))?);
    match serde_json::to_value(&ud) {
        Ok(v) => panic!("expected serialization error, got {}", v),
        Err(serde_json::Error { .. }) => {}
    }

    let func = lua.create_function(|_, _: ()| Ok(()))?;
    match serde_json::to_value(&Value::Function(func.clone())) {
        Ok(v) => panic!("expected serialization error, got {}", v),
        Err(serde_json::Error { .. }) => {}
    }

    let thr = lua.create_thread(func)?;
    match serde_json::to_value(&Value::Thread(thr)) {
        Ok(v) => panic!("expected serialization error, got {}", v),
        Err(serde_json::Error { .. }) => {}
    }

    Ok(())
}

#[test]
fn test_to_value_struct() -> LuaResult<()> {
    let lua = Lua::new();
    let globals = lua.globals();
    globals.set("null", lua.null())?;

    #[derive(Serialize)]
    struct Test {
        name: String,
        key: i64,
        data: Option<bool>,
    }

    let test = Test {
        name: "alex".to_string(),
        key: -16,
        data: None,
    };

    globals.set("value", lua.to_value(&test)?)?;
    lua.load(
        r#"
            assert(value["name"] == "alex")
            assert(value["key"] == -16)
            assert(value["data"] == null)
        "#,
    )
    .exec()
}

#[test]
fn test_to_value_enum() -> LuaResult<()> {
    let lua = Lua::new();
    let globals = lua.globals();

    #[derive(Serialize)]
    enum E {
        Unit,
        Integer(u32),
        Tuple(u32, u32),
        Struct { a: u32 },
    }

    let u = E::Unit;
    globals.set("value", lua.to_value(&u)?)?;
    lua.load(r#"assert(value == "Unit")"#).exec()?;

    let n = E::Integer(1);
    globals.set("value", lua.to_value(&n)?)?;
    lua.load(r#"assert(value["Integer"] == 1)"#).exec()?;

    let t = E::Tuple(1, 2);
    globals.set("value", lua.to_value(&t)?)?;
    lua.load(
        r#"
            assert(value["Tuple"][1] == 1)
            assert(value["Tuple"][2] == 2)
        "#,
    )
    .exec()?;

    let s = E::Struct { a: 1 };
    globals.set("value", lua.to_value(&s)?)?;
    lua.load(r#"assert(value["Struct"]["a"] == 1)"#).exec()?;
    Ok(())
}

#[test]
fn test_to_value_with_options() -> Result<(), Box<dyn std::error::Error>> {
    let lua = Lua::new();
    let globals = lua.globals();
    globals.set("null", lua.null())?;

    // set_array_metatable
    let data = lua.to_value_with(
        &Vec::<i32>::new(),
        SerializeOptions::new().set_array_metatable(false),
    )?;
    globals.set("data", data)?;
    lua.load(
        r#"
        assert(type(data) == "table" and #data == 0)
        assert(getmetatable(data) == nil)
    "#,
    )
    .exec()?;

    #[derive(Serialize)]
    struct UnitStruct;

    #[derive(Serialize)]
    struct MyData {
        map: HashMap<&'static str, Option<i32>>,
        unit: (),
        unitstruct: UnitStruct,
    }

    // serialize_none_to_null
    let mut map = HashMap::new();
    map.insert("key", None);
    let mydata = MyData {
        map,
        unit: (),
        unitstruct: UnitStruct,
    };
    let data2 = lua.to_value_with(
        &mydata,
        SerializeOptions::new().serialize_none_to_null(false),
    )?;
    globals.set("data2", data2)?;
    lua.load(
        r#"
        assert(data2.map.key == nil)
        assert(data2.unit == null)
        assert(data2.unitstruct == null)
    "#,
    )
    .exec()?;

    // serialize_unit_to_null
    let data3 = lua.to_value_with(
        &mydata,
        SerializeOptions::new().serialize_unit_to_null(false),
    )?;
    globals.set("data3", data3)?;
    lua.load(
        r#"
        assert(data3.map.key == null)
        assert(data3.unit == nil)
        assert(data3.unitstruct == nil)
    "#,
    )
    .exec()?;

    Ok(())
}

#[test]
fn test_from_value_nested_tables() -> Result<(), Box<dyn std::error::Error>> {
    let lua = Lua::new();

    let value = lua
        .load(
            r#"
            local table_a = {a = "a"}
            local table_b = {"b"}
            return {
                a = table_a,
                b = {table_b, table_b},
                ab = {a = table_a, b = table_b}
            }
        "#,
        )
        .eval::<Value>()?;
    let got = lua.from_value::<serde_json::Value>(value)?;
    assert_eq!(
        got,
        serde_json::json!({
            "a": {"a": "a"},
            "b": [["b"], ["b"]],
            "ab": {"a": {"a": "a"}, "b": ["b"]},
        })
    );

    Ok(())
}

#[test]
fn test_from_value_struct() -> Result<(), Box<dyn std::error::Error>> {
    let lua = Lua::new();

    #[derive(Deserialize, PartialEq, Debug)]
    struct Test {
        int: u32,
        seq: Vec<String>,
        map: HashMap<i32, i32>,
        empty: Vec<()>,
        tuple: (u8, u8, u8),
    }

    let value = lua
        .load(
            r#"
            {
                int = 1,
                seq = {"a", "b"},
                map = {2, [4] = 1},
                empty = {},
                tuple = {10, 20, 30},
            }
        "#,
        )
        .eval::<Value>()?;
    let got = lua.from_value(value)?;
    assert_eq!(
        Test {
            int: 1,
            seq: vec!["a".into(), "b".into()],
            map: vec![(1, 2), (4, 1)].into_iter().collect(),
            empty: vec![],
            tuple: (10, 20, 30),
        },
        got
    );

    Ok(())
}

#[test]
fn test_from_value_enum() -> Result<(), Box<dyn std::error::Error>> {
    let lua = Lua::new();

    #[derive(Deserialize, PartialEq, Debug)]
    enum E {
        Unit,
        Integer(u32),
        Tuple(u32, u32),
        Struct { a: u32 },
    }

    let value = lua.load(r#""Unit""#).eval()?;
    let got = lua.from_value(value)?;
    assert_eq!(E::Unit, got);

    let value = lua.load(r#"{Integer = 1}"#).eval()?;
    let got = lua.from_value(value)?;
    assert_eq!(E::Integer(1), got);

    let value = lua.load(r#"{Tuple = {1, 2}}"#).eval()?;
    let got = lua.from_value(value)?;
    assert_eq!(E::Tuple(1, 2), got);

    let value = lua.load(r#"{Struct = {a = 3}}"#).eval()?;
    let got = lua.from_value(value)?;
    assert_eq!(E::Struct { a: 3 }, got);

    Ok(())
}

#[test]
fn test_from_value_enum_untagged() -> Result<(), Box<dyn std::error::Error>> {
    let lua = Lua::new();
    lua.globals().set("null", lua.null())?;

    #[derive(Deserialize, PartialEq, Debug)]
    #[serde(untagged)]
    enum Eut {
        Unit,
        Integer(u64),
        Tuple(u32, u32),
        Struct { a: u32 },
    }

    let value = lua.load(r#"null"#).eval()?;
    let got = lua.from_value(value)?;
    assert_eq!(Eut::Unit, got);

    let value = lua.load(r#"1"#).eval()?;
    let got = lua.from_value(value)?;
    assert_eq!(Eut::Integer(1), got);

    let value = lua.load(r#"{3, 1}"#).eval()?;
    let got = lua.from_value(value)?;
    assert_eq!(Eut::Tuple(3, 1), got);

    let value = lua.load(r#"{a = 10}"#).eval()?;
    let got = lua.from_value(value)?;
    assert_eq!(Eut::Struct { a: 10 }, got);

    let value = lua.load(r#"{b = 12}"#).eval()?;
    match lua.from_value::<Eut>(value) {
        Ok(v) => panic!("expected Error::DeserializeError, got {:?}", v),
        Err(Error::DeserializeError(_)) => {}
        Err(e) => panic!("expected Error::DeserializeError, got {}", e),
    }

    Ok(())
}

#[test]
fn test_from_value_with_options() -> Result<(), Box<dyn std::error::Error>> {
    let lua = Lua::new();

    // Deny unsupported types by default
    let value = Value::Function(lua.create_function(|_, ()| Ok(()))?);
    match lua.from_value::<Option<String>>(value) {
        Ok(v) => panic!("expected deserialization error, got {:?}", v),
        Err(Error::DeserializeError(err)) => {
            assert!(err.contains("unsupported value type"))
        }
        Err(err) => panic!("expected `DeserializeError` error, got {:?}", err),
    };

    // Allow unsupported types
    let value = Value::Function(lua.create_function(|_, ()| Ok(()))?);
    let options = DeserializeOptions::new().deny_unsupported_types(false);
    assert_eq!(lua.from_value_with::<()>(value, options)?, ());

    // Allow unsupported types (in a table seq)
    let value = lua.load(r#"{"a", "b", function() end, "c"}"#).eval()?;
    let options = DeserializeOptions::new().deny_unsupported_types(false);
    assert_eq!(
        lua.from_value_with::<Vec<String>>(value, options)?,
        vec!["a".to_string(), "b".to_string(), "c".to_string()]
    );

    // Deny recursive tables by default
    let value = lua.load(r#"local t = {}; t.t = t; return t"#).eval()?;
    match lua.from_value::<HashMap<String, Option<String>>>(value) {
        Ok(v) => panic!("expected deserialization error, got {:?}", v),
        Err(Error::DeserializeError(err)) => {
            assert!(err.contains("recursive table detected"))
        }
        Err(err) => panic!("expected `DeserializeError` error, got {:?}", err),
    };

    // Check recursion when using `Serialize` impl
    let t = lua.create_table()?;
    t.set("t", t.clone())?;
    assert!(serde_json::to_string(&t).is_err());

    // Serialize Lua globals table
    #[derive(Debug, Deserialize)]
    struct Globals {
        hello: String,
    }
    let options = DeserializeOptions::new()
        .deny_unsupported_types(false)
        .deny_recursive_tables(false);
    lua.load(r#"hello = "world""#).exec()?;
    let globals: Globals = lua.from_value_with(Value::Table(lua.globals()), options)?;
    assert_eq!(globals.hello, "world");

    Ok(())
}