lean-rs 0.1.0

Safe Rust bindings for hosting Lean 4 capabilities: runtime initialization, owned and borrowed object handles, typed first-order ABI conversions, compiled module loading, exported function calls, semantic handles, bounded meta services, batching, and session pooling.
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

//! Round-trip tests for the four semantic handles.
//!
//! Each handle is exercised through the prompt-12
//! [`crate::module::LeanModule::exported`] dispatch path against the
//! `LeanRsFixture.Handles` capability. Construction and inspection happen
//! exclusively in Lean code; the Rust side only carries the handle.

#![allow(clippy::expect_used, clippy::panic)]

use std::path::PathBuf;

use crate::module::LeanLibrary;
use crate::runtime::LeanRuntime;
use crate::{LeanDeclaration, LeanExpr, LeanLevel, LeanName};

// -- fixture setup -------------------------------------------------------
// Mirrors the per-test-module pattern in `abi/tests.rs` and
// `module/tests.rs`: each test opens its own `LeanLibrary` against the
// process-wide runtime singleton; dlopen + symbol-table walks are backed
// by the OS page cache for the second-and-later open of the same file.

fn fixture_dylib_path() -> PathBuf {
    let manifest_dir = PathBuf::from(env!("CARGO_MANIFEST_DIR"));
    let workspace = manifest_dir
        .parent()
        .and_then(std::path::Path::parent)
        .expect("crates/<name>/ lives two directories beneath the workspace root");
    let dylib_extension = if cfg!(target_os = "macos") { "dylib" } else { "so" };
    let lib_dir = workspace
        .join("fixtures")
        .join("lean")
        .join(".lake")
        .join("build")
        .join("lib");
    let new_style = lib_dir.join(format!("liblean__rs__fixture_LeanRsFixture.{dylib_extension}"));
    let old_style = lib_dir.join(format!("libLeanRsFixture.{dylib_extension}"));
    if old_style.is_file() && !new_style.is_file() {
        old_style
    } else {
        new_style
    }
}

fn runtime() -> &'static LeanRuntime {
    LeanRuntime::init().expect("Lean runtime initialisation must succeed")
}

fn fixture_library() -> LeanLibrary<'static> {
    let path = fixture_dylib_path();
    assert!(
        path.exists(),
        "fixture dylib not found at {} — run `cd fixtures/lean && lake build`",
        path.display(),
    );
    LeanLibrary::open(runtime(), &path).expect("fixture dylib opens cleanly")
}

// -- LeanName ------------------------------------------------------------

#[test]
fn name_round_trips_through_lean_authored_display() {
    let library = fixture_library();
    let module = library
        .initialize_module("lean_rs_fixture", "LeanRsFixture")
        .expect("init root module");

    let mk_anon = module
        .exported::<((),), LeanName<'_>>("lean_rs_fixture_name_anonymous")
        .expect("lookup name_anonymous");
    let mk_str = module
        .exported::<(LeanName<'_>, String), LeanName<'_>>("lean_rs_fixture_name_mk_str")
        .expect("lookup name_mk_str");
    let to_str = module
        .exported::<(LeanName<'_>,), String>("lean_rs_fixture_name_to_string")
        .expect("lookup name_to_string");

    let root = mk_anon.call(()).expect("call name_anonymous");
    let child = mk_str.call(root, "Demo".to_owned()).expect("call name_mk_str");
    let rendered = to_str.call(child).expect("call name_to_string");

    assert!(
        rendered.contains("Demo"),
        "Lean-rendered name must contain the leaf component, got {rendered:?}",
    );
}

#[test]
fn name_equality_via_fixture_export() {
    let library = fixture_library();
    let module = library
        .initialize_module("lean_rs_fixture", "LeanRsFixture")
        .expect("init root module");

    let mk_anon = module
        .exported::<((),), LeanName<'_>>("lean_rs_fixture_name_anonymous")
        .expect("lookup name_anonymous");
    let mk_str = module
        .exported::<(LeanName<'_>, String), LeanName<'_>>("lean_rs_fixture_name_mk_str")
        .expect("lookup name_mk_str");
    let beq = module
        .exported::<(LeanName<'_>, LeanName<'_>), bool>("lean_rs_fixture_name_beq")
        .expect("lookup name_beq");

    let a = mk_str
        .call(mk_anon.call(()).expect("anon a"), "Foo".to_owned())
        .expect("mk a");
    let b = mk_str
        .call(mk_anon.call(()).expect("anon b"), "Foo".to_owned())
        .expect("mk b");
    let c = mk_str
        .call(mk_anon.call(()).expect("anon c"), "Bar".to_owned())
        .expect("mk c");

    assert!(beq.call(a.clone(), b).expect("beq equal"));
    assert!(!beq.call(a, c).expect("beq differ"));
}

// -- LeanLevel -----------------------------------------------------------

#[test]
fn level_round_trips_succ_zero() {
    let library = fixture_library();
    let module = library
        .initialize_module("lean_rs_fixture", "LeanRsFixture")
        .expect("init root module");

    let zero = module
        .exported::<((),), LeanLevel<'_>>("lean_rs_fixture_level_zero")
        .expect("lookup level_zero");
    let succ = module
        .exported::<(LeanLevel<'_>,), LeanLevel<'_>>("lean_rs_fixture_level_succ")
        .expect("lookup level_succ");
    let to_str = module
        .exported::<(LeanLevel<'_>,), String>("lean_rs_fixture_level_to_string")
        .expect("lookup level_to_string");

    let one = succ.call(zero.call(()).expect("zero")).expect("succ zero");
    let rendered = to_str.call(one).expect("level_to_string");

    // Lean prints `succ zero` as `"1"`; assert a non-empty render and a
    // digit somewhere so the test is robust against pretty-printer
    // formatting tweaks across toolchain updates.
    assert!(
        rendered.chars().any(|c| c.is_ascii_digit()),
        "Lean-rendered succ-zero must contain a digit, got {rendered:?}",
    );
}

#[test]
fn level_equality_via_fixture_export() {
    let library = fixture_library();
    let module = library
        .initialize_module("lean_rs_fixture", "LeanRsFixture")
        .expect("init root module");

    let zero = module
        .exported::<((),), LeanLevel<'_>>("lean_rs_fixture_level_zero")
        .expect("lookup level_zero");
    let succ = module
        .exported::<(LeanLevel<'_>,), LeanLevel<'_>>("lean_rs_fixture_level_succ")
        .expect("lookup level_succ");
    let beq = module
        .exported::<(LeanLevel<'_>, LeanLevel<'_>), bool>("lean_rs_fixture_level_beq")
        .expect("lookup level_beq");

    let a = succ.call(zero.call(()).expect("zero a")).expect("succ a");
    let b = succ.call(zero.call(()).expect("zero b")).expect("succ b");
    let c = zero.call(()).expect("zero c");

    assert!(beq.call(a.clone(), b).expect("beq equal"));
    assert!(!beq.call(a, c).expect("beq differ"));
}

// -- LeanExpr ------------------------------------------------------------

#[test]
fn expr_const_nat_round_trips() {
    let library = fixture_library();
    let module = library
        .initialize_module("lean_rs_fixture", "LeanRsFixture")
        .expect("init root module");

    let const_nat = module
        .exported::<((),), LeanExpr<'_>>("lean_rs_fixture_expr_const_nat")
        .expect("lookup expr_const_nat");
    let to_str = module
        .exported::<(LeanExpr<'_>,), String>("lean_rs_fixture_expr_to_string")
        .expect("lookup expr_to_string");

    let rendered = to_str
        .call(const_nat.call(()).expect("const Nat"))
        .expect("expr_to_string");

    assert!(
        rendered.contains("Nat"),
        "Lean-rendered `.const ``Nat []` must contain \"Nat\", got {rendered:?}",
    );
}

#[test]
fn expr_app_round_trips() {
    let library = fixture_library();
    let module = library
        .initialize_module("lean_rs_fixture", "LeanRsFixture")
        .expect("init root module");

    let const_nat = module
        .exported::<((),), LeanExpr<'_>>("lean_rs_fixture_expr_const_nat")
        .expect("lookup expr_const_nat");
    let app = module
        .exported::<(LeanExpr<'_>, LeanExpr<'_>), LeanExpr<'_>>("lean_rs_fixture_expr_app")
        .expect("lookup expr_app");
    let bvar = module
        .exported::<(u64,), LeanExpr<'_>>("lean_rs_fixture_expr_bvar")
        .expect("lookup expr_bvar");

    let f = const_nat.call(()).expect("f");
    let x = bvar.call(0).expect("x");
    let applied = app.call(f, x).expect("expr_app");
    // Round-tripped through Lean: passing it back through expr_app
    // should not error and should produce another distinct expression.
    let again = app
        .call(applied.clone(), bvar.call(1).expect("y"))
        .expect("expr_app second time");
    drop(again);
}

#[test]
fn expr_equality_via_fixture_export() {
    let library = fixture_library();
    let module = library
        .initialize_module("lean_rs_fixture", "LeanRsFixture")
        .expect("init root module");

    let const_nat = module
        .exported::<((),), LeanExpr<'_>>("lean_rs_fixture_expr_const_nat")
        .expect("lookup expr_const_nat");
    let bvar = module
        .exported::<(u64,), LeanExpr<'_>>("lean_rs_fixture_expr_bvar")
        .expect("lookup expr_bvar");
    let beq = module
        .exported::<(LeanExpr<'_>, LeanExpr<'_>), bool>("lean_rs_fixture_expr_beq")
        .expect("lookup expr_beq");

    let a = const_nat.call(()).expect("a");
    let b = const_nat.call(()).expect("b");
    let c = bvar.call(0).expect("c");

    assert!(beq.call(a.clone(), b).expect("beq equal"));
    assert!(!beq.call(a, c).expect("beq differ"));
}

// -- LeanDeclaration -----------------------------------------------------

#[test]
fn declaration_demo_axiom_round_trips() {
    let library = fixture_library();
    let module = library
        .initialize_module("lean_rs_fixture", "LeanRsFixture")
        .expect("init root module");

    let mk_anon = module
        .exported::<((),), LeanName<'_>>("lean_rs_fixture_name_anonymous")
        .expect("lookup name_anonymous");
    let mk_str = module
        .exported::<(LeanName<'_>, String), LeanName<'_>>("lean_rs_fixture_name_mk_str")
        .expect("lookup name_mk_str");
    let demo_axiom = module
        .exported::<(LeanName<'_>,), LeanDeclaration<'_>>("lean_rs_fixture_declaration_demo_axiom")
        .expect("lookup declaration_demo_axiom");
    let render = module
        .exported::<(LeanDeclaration<'_>,), String>("lean_rs_fixture_declaration_name_to_string")
        .expect("lookup declaration_name_to_string");

    let name = mk_str
        .call(mk_anon.call(()).expect("anon"), "DemoAxiom".to_owned())
        .expect("mk DemoAxiom");
    let decl = demo_axiom.call(name).expect("demo_axiom");
    let rendered = render.call(decl).expect("render");

    assert!(
        rendered.starts_with("axiom"),
        "expected axiom-prefixed render, got {rendered:?}"
    );
    assert!(
        rendered.contains("DemoAxiom"),
        "expected name leaf in render, got {rendered:?}"
    );
}