luars 0.17.0

A library for lua 5.5 runtime implementation 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

/// Tests for RClosure (Rust closures registered as Lua functions)
use crate::lua_value::LuaValue;
use crate::lua_vm::{LuaResult, LuaState, LuaVM, SafeOption};

#[test]
fn test_rclosure_basic_no_return() {
    let mut vm = LuaVM::new(SafeOption::default());
    vm.open_stdlib(crate::stdlib::Stdlib::All).unwrap();

    let func = vm
        .create_closure(|_state: &mut LuaState| -> LuaResult<usize> { Ok(0) })
        .unwrap();
    vm.set_global("myfn", func).unwrap();

    let result = vm.execute("myfn(); return 42");
    assert!(result.is_ok(), "RClosure call failed: {:?}", result.err());
    let vals = result.unwrap();
    assert_eq!(vals[0].as_integer(), Some(42));
}

#[test]
fn test_rclosure_returns_value() {
    let mut vm = LuaVM::new(SafeOption::default());
    vm.open_stdlib(crate::stdlib::Stdlib::All).unwrap();

    let func = vm
        .create_closure(|state: &mut LuaState| -> LuaResult<usize> {
            state.push_value(LuaValue::integer(123))?;
            Ok(1)
        })
        .unwrap();
    vm.set_global("myfn", func).unwrap();

    let result = vm.execute("return myfn()");
    assert!(result.is_ok(), "RClosure call failed: {:?}", result.err());
    let vals = result.unwrap();
    assert_eq!(vals[0].as_integer(), Some(123));
}

#[test]
fn test_rclosure_reads_args() {
    let mut vm = LuaVM::new(SafeOption::default());
    vm.open_stdlib(crate::stdlib::Stdlib::All).unwrap();

    let func = vm
        .create_closure(|state: &mut LuaState| -> LuaResult<usize> {
            let a = state.get_arg(1).unwrap_or_default();
            let b = state.get_arg(2).unwrap_or_default();
            let sum = a.as_integer().unwrap_or(0) + b.as_integer().unwrap_or(0);
            state.push_value(LuaValue::integer(sum))?;
            Ok(1)
        })
        .unwrap();
    vm.set_global("add", func).unwrap();

    let result = vm.execute("return add(10, 32)");
    assert!(result.is_ok(), "{:?}", result.err());
    assert_eq!(result.unwrap()[0].as_integer(), Some(42));
}

#[test]
fn test_rclosure_captures_state() {
    use std::cell::Cell;
    use std::rc::Rc;

    let mut vm = LuaVM::new(SafeOption::default());
    vm.open_stdlib(crate::stdlib::Stdlib::All).unwrap();

    let counter = Rc::new(Cell::new(0i64));
    let counter_clone = counter.clone();

    let func = vm
        .create_closure(move |state: &mut LuaState| -> LuaResult<usize> {
            let current = counter_clone.get();
            counter_clone.set(current + 1);
            state.push_value(LuaValue::integer(current + 1))?;
            Ok(1)
        })
        .unwrap();
    vm.set_global("next_id", func).unwrap();

    let result = vm.execute(
        r#"
        local a = next_id()
        local b = next_id()
        local c = next_id()
        return a, b, c
        "#,
    );
    assert!(result.is_ok(), "{:?}", result.err());
    let vals = result.unwrap();
    assert_eq!(vals[0].as_integer(), Some(1));
    assert_eq!(vals[1].as_integer(), Some(2));
    assert_eq!(vals[2].as_integer(), Some(3));
    assert_eq!(counter.get(), 3);
}

#[test]
fn test_rclosure_with_upvalues() {
    let mut vm = LuaVM::new(SafeOption::default());
    vm.open_stdlib(crate::stdlib::Stdlib::All).unwrap();

    let upvalues = vec![LuaValue::integer(100)];
    let func = vm
        .create_closure_with_upvalues(
            |state: &mut LuaState| -> LuaResult<usize> {
                // Get the function value from the stack (func_idx position)
                // The upvalues are stored on the RClosureFunction, accessed via the function value
                let frame = &state.call_stack[state.call_depth() - 1];
                let func_idx = frame.base - frame.func_offset as usize;
                let func_val = state.stack_get(func_idx).unwrap();
                let rclosure = func_val.as_rclosure().unwrap();
                let offset = rclosure.upvalues()[0].as_integer().unwrap_or(0);

                let arg = state.get_arg(1).and_then(|v| v.as_integer()).unwrap_or(0);
                state.push_value(LuaValue::integer(arg + offset))?;
                Ok(1)
            },
            upvalues,
        )
        .unwrap();
    vm.set_global("add_offset", func).unwrap();

    let result = vm.execute("return add_offset(42)");
    assert!(result.is_ok(), "{:?}", result.err());
    assert_eq!(result.unwrap()[0].as_integer(), Some(142));
}

#[test]
fn test_rclosure_multiple_returns() {
    let mut vm = LuaVM::new(SafeOption::default());
    vm.open_stdlib(crate::stdlib::Stdlib::All).unwrap();

    let func = vm
        .create_closure(|state: &mut LuaState| -> LuaResult<usize> {
            state.push_value(LuaValue::integer(1))?;
            state.push_value(LuaValue::integer(2))?;
            state.push_value(LuaValue::integer(3))?;
            Ok(3)
        })
        .unwrap();
    vm.set_global("three", func).unwrap();

    let result = vm.execute("return three()");
    assert!(result.is_ok(), "{:?}", result.err());
    let vals = result.unwrap();
    assert_eq!(vals.len(), 3);
    assert_eq!(vals[0].as_integer(), Some(1));
    assert_eq!(vals[1].as_integer(), Some(2));
    assert_eq!(vals[2].as_integer(), Some(3));
}

#[test]
fn test_rclosure_called_from_lua_closure() {
    let mut vm = LuaVM::new(SafeOption::default());
    vm.open_stdlib(crate::stdlib::Stdlib::All).unwrap();

    let func = vm
        .create_closure(|state: &mut LuaState| -> LuaResult<usize> {
            let x = state.get_arg(1).and_then(|v| v.as_integer()).unwrap_or(0);
            state.push_value(LuaValue::integer(x * x))?;
            Ok(1)
        })
        .unwrap();
    vm.set_global("square", func).unwrap();

    let result = vm.execute(
        r#"
        local function apply(f, x)
            return f(x)
        end
        return apply(square, 7)
        "#,
    );
    assert!(result.is_ok(), "{:?}", result.err());
    assert_eq!(result.unwrap()[0].as_integer(), Some(49));
}

#[test]
fn test_rclosure_in_table() {
    let mut vm = LuaVM::new(SafeOption::default());
    vm.open_stdlib(crate::stdlib::Stdlib::All).unwrap();

    let func = vm
        .create_closure(|state: &mut LuaState| -> LuaResult<usize> {
            state.push_value(LuaValue::integer(999))?;
            Ok(1)
        })
        .unwrap();
    vm.set_global("magic", func).unwrap();

    let result = vm.execute(
        r#"
        local t = { fn = magic }
        return t.fn()
        "#,
    );
    assert!(result.is_ok(), "{:?}", result.err());
    assert_eq!(result.unwrap()[0].as_integer(), Some(999));
}

#[test]
fn test_rclosure_tail_call() {
    let mut vm = LuaVM::new(SafeOption::default());
    vm.open_stdlib(crate::stdlib::Stdlib::All).unwrap();

    let func = vm
        .create_closure(|state: &mut LuaState| -> LuaResult<usize> {
            let x = state.get_arg(1).and_then(|v| v.as_integer()).unwrap_or(0);
            state.push_value(LuaValue::integer(x + 1))?;
            Ok(1)
        })
        .unwrap();
    vm.set_global("inc", func).unwrap();

    // Lua tail-calls the RClosure
    let result = vm.execute(
        r#"
        local function wrapper(x)
            return inc(x)
        end
        return wrapper(41)
        "#,
    );
    assert!(result.is_ok(), "{:?}", result.err());
    assert_eq!(result.unwrap()[0].as_integer(), Some(42));
}

#[test]
fn test_rclosure_error_propagation() {
    let mut vm = LuaVM::new(SafeOption::default());
    vm.open_stdlib(crate::stdlib::Stdlib::All).unwrap();

    let func = vm
        .create_closure(|state: &mut LuaState| -> LuaResult<usize> {
            Err(state.error("custom error from Rust closure".to_string()))
        })
        .unwrap();
    vm.set_global("fail_fn", func).unwrap();

    let result = vm.execute(
        r#"
        local ok, msg = pcall(fail_fn)
        assert(not ok)
        assert(type(msg) == "string")
        return msg
        "#,
    );
    assert!(result.is_ok(), "{:?}", result.err());
}

#[test]
fn test_rclosure_gc_survives() {
    let mut vm = LuaVM::new(SafeOption::default());
    vm.open_stdlib(crate::stdlib::Stdlib::All).unwrap();

    let func = vm
        .create_closure(|state: &mut LuaState| -> LuaResult<usize> {
            state.push_value(LuaValue::integer(77))?;
            Ok(1)
        })
        .unwrap();
    vm.set_global("gc_test", func).unwrap();

    // Force GC then call the function
    let result = vm.execute(
        r#"
        collectgarbage("collect")
        collectgarbage("collect")
        return gc_test()
        "#,
    );
    assert!(result.is_ok(), "{:?}", result.err());
    assert_eq!(result.unwrap()[0].as_integer(), Some(77));
}

#[test]
fn test_rclosure_type_function() {
    let mut vm = LuaVM::new(SafeOption::default());
    vm.open_stdlib(crate::stdlib::Stdlib::All).unwrap();

    let func = vm
        .create_closure(|_state: &mut LuaState| -> LuaResult<usize> { Ok(0) })
        .unwrap();
    vm.set_global("myfn", func).unwrap();

    let result = vm.execute("return type(myfn)");
    assert!(result.is_ok(), "{:?}", result.err());
    let vals = result.unwrap();
    assert_eq!(vals[0].as_str(), Some("function"));
}