symplex 0.2.0

Exact symbolic mathematics for Rust: calculus, summation, solving, linear algebra, transforms, compile-time dimensional analysis, and Rust/C code generation
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

//! Integration tests for the `to_rust_fn` codegen feature.

use symplex::prelude::*;

/// Helper: verify generated code has balanced braces and required structure.
fn assert_valid_rust_structure(code: &str, fn_name: &str) {
    assert!(
        code.contains(&format!("pub fn {fn_name}")),
        "missing function signature 'pub fn {fn_name}' in:\n{code}"
    );
    assert!(
        code.contains("-> f64"),
        "missing return type '-> f64' in:\n{code}"
    );
    let opens = code.chars().filter(|&c| c == '{').count();
    let closes = code.chars().filter(|&c| c == '}').count();
    assert_eq!(
        opens, closes,
        "unbalanced braces ({opens} open vs {closes} close) in:\n{code}"
    );
    let open_parens = code.chars().filter(|&c| c == '(').count();
    let close_parens = code.chars().filter(|&c| c == ')').count();
    assert_eq!(
        open_parens, close_parens,
        "unbalanced parentheses ({open_parens} open vs {close_parens} close) in:\n{code}"
    );
}

#[test]
fn codegen_simple_polynomial() {
    let ctx = Context::new();
    let x = ctx.symbol("x");
    let f = x.powi(2) + &x * 2 + 1;
    let code = f.to_rust_fn("poly", &["x"]).unwrap();
    assert!(
        code.contains("pub fn poly(x: f64) -> f64"),
        "missing function signature in:\n{code}"
    );
    // x^2 should use powi(2) for efficiency
    assert!(
        code.contains("powi(2)"),
        "expected powi(2) for x^2 in:\n{code}"
    );
    // Should end with a closing brace
    assert!(code.trim_end().ends_with('}'), "missing closing brace");
}

#[test]
fn codegen_trig() {
    let ctx = Context::new();
    let x = ctx.symbol("x");
    let f = x.sin() + x.cos();
    let code = f.to_rust_fn("trig", &["x"]).unwrap();
    assert!(code.contains(".sin()"), "missing sin() in:\n{code}");
    assert!(code.contains(".cos()"), "missing cos() in:\n{code}");
    assert!(code.contains("pub fn trig(x: f64) -> f64"));
}

#[test]
fn codegen_two_vars() {
    let ctx = Context::new();
    let x = ctx.symbol("x");
    let y = ctx.symbol("y");
    let f = x.powi(2) + y.powi(2);
    let code = f.to_rust_fn("sum_sq", &["x", "y"]).unwrap();
    assert!(
        code.contains("x: f64, y: f64"),
        "missing two-parameter signature in:\n{code}"
    );
    assert!(code.contains("pub fn sum_sq"));
}

#[test]
fn codegen_constants() {
    let ctx = Context::new();
    let x = ctx.symbol("x");
    let pi = ctx.pi();
    let e = ctx.e();
    let f = &pi * &x + e;
    let code = f.to_rust_fn("with_consts", &["x"]).unwrap();
    assert!(
        code.contains("PI") || code.contains("std::f64::consts"),
        "missing PI constant in:\n{code}"
    );
    assert!(
        code.contains("E") || code.contains("std::f64::consts::E"),
        "missing E constant in:\n{code}"
    );
}

#[test]
fn codegen_free_symbol_error() {
    let ctx = Context::new();
    let x = ctx.symbol("x");
    let y = ctx.symbol("y");
    let f = &x + &y;
    // y is not listed as an argument, so it should be a free symbol error
    let result = f.to_rust_fn("partial", &["x"]);
    assert!(result.is_err(), "expected error for free symbol y");
}

#[test]
fn codegen_exp_ln() {
    let ctx = Context::new();
    let x = ctx.symbol("x");
    let f = x.exp() + x.ln();
    let code = f.to_rust_fn("expln", &["x"]).unwrap();
    assert!(code.contains(".exp()"), "missing exp() in:\n{code}");
    assert!(code.contains(".ln()"), "missing ln() in:\n{code}");
}

#[test]
fn codegen_sqrt_via_pow_half() {
    let ctx = Context::new();
    let x = ctx.symbol("x");
    let f = x.sqrt();
    let code = f.to_rust_fn("my_sqrt", &["x"]).unwrap();
    // sqrt is Pow(x, 1/2) internally; codegen should emit .sqrt()
    assert!(
        code.contains(".sqrt()"),
        "expected .sqrt() for x^(1/2) in:\n{code}"
    );
}

#[test]
fn codegen_hyperbolic() {
    let ctx = Context::new();
    let x = ctx.symbol("x");
    let f = x.sinh() + x.cosh() + x.tanh();
    let code = f.to_rust_fn("hyp", &["x"]).unwrap();
    assert!(code.contains(".sinh()"), "missing sinh() in:\n{code}");
    assert!(code.contains(".cosh()"), "missing cosh() in:\n{code}");
    assert!(code.contains(".tanh()"), "missing tanh() in:\n{code}");
}

#[test]
fn codegen_abs_and_sign() {
    let ctx = Context::new();
    let x = ctx.symbol("x");
    let f = x.abs() + x.sign();
    let code = f.to_rust_fn("abs_sign", &["x"]).unwrap();
    assert!(code.contains(".abs()"), "missing abs() in:\n{code}");
    // sign(x) is codegen'd as an inline if-else (not .signum()) to
    // correctly handle sign(0) = 0  (Rust's f64::signum treats ±0 differently).
    assert!(
        code.contains("if x > 0.0"),
        "missing sign if-else in:\n{code}"
    );
}

#[test]
fn codegen_negative_exponent_uses_powi() {
    let ctx = Context::new();
    let x = ctx.symbol("x");
    let f = x.pow(&ctx.int(-2));
    let code = f.to_rust_fn("inv_sq", &["x"]).unwrap();
    assert!(
        code.contains("powi(-2)"),
        "expected powi(-2) for x^(-2) in:\n{code}"
    );
}

#[test]
fn codegen_no_args_constant_expr() {
    let ctx = Context::new();
    let pi = ctx.pi();
    let f = pi.powi(2);
    let code = f.to_rust_fn("pi_squared", &[]).unwrap();
    assert!(
        code.contains("pub fn pi_squared() -> f64"),
        "expected zero-arg function in:\n{code}"
    );
    assert!(code.contains("PI"), "expected PI constant in:\n{code}");
}

#[test]
fn codegen_inverse_trig() {
    let ctx = Context::new();
    let x = ctx.symbol("x");
    let f = x.asin() + x.acos() + x.atan();
    let code = f.to_rust_fn("inv_trig", &["x"]).unwrap();
    assert!(code.contains(".asin()"), "missing asin() in:\n{code}");
    assert!(code.contains(".acos()"), "missing acos() in:\n{code}");
    assert!(code.contains(".atan()"), "missing atan() in:\n{code}");
}

#[test]
fn codegen_complex_expression() {
    // A more realistic expression: sin(x)^2 + cos(x)^2 (which may or may not simplify)
    let ctx = Context::new();
    let x = ctx.symbol("x");
    let f = x.sin().powi(2) + x.cos().powi(2);
    // Whether it simplifies to 1 or keeps the form, codegen should succeed
    let code = f.to_rust_fn("trig_identity", &["x"]).unwrap();
    assert_valid_rust_structure(&code, "trig_identity");
}

// ═══════════════════════════════════════════════════════════════════════════
// Wave 8: Verify generated code syntax
// ═══════════════════════════════════════════════════════════════════════════

#[test]
fn codegen_output_is_valid_rust_syntax() {
    let ctx = Context::new();
    let x = ctx.symbol("x");
    let code = x.powi(2).to_rust_fn("square", &["x"]).unwrap();
    // Verify it contains required elements
    assert!(code.contains("fn square"), "missing fn square in:\n{code}");
    assert!(code.contains("-> f64"), "missing -> f64 in:\n{code}");
    // Verify balanced braces
    let opens = code.chars().filter(|&c| c == '{').count();
    let closes = code.chars().filter(|&c| c == '}').count();
    assert_eq!(opens, closes, "unbalanced braces in: {code}");
    // Verify balanced parentheses
    let open_parens = code.chars().filter(|&c| c == '(').count();
    let close_parens = code.chars().filter(|&c| c == ')').count();
    assert_eq!(
        open_parens, close_parens,
        "unbalanced parentheses in: {code}"
    );
}

#[test]
fn codegen_trig_structure_valid() {
    let ctx = Context::new();
    let x = ctx.symbol("x");
    // sin(x)^2 + cos(x) + tan(x)
    let f = x.sin().powi(2) + x.cos() + x.tan();
    let code = f.to_rust_fn("trig_combo", &["x"]).unwrap();
    assert_valid_rust_structure(&code, "trig_combo");
    assert!(code.contains(".sin()"), "missing sin() in:\n{code}");
    assert!(code.contains(".cos()"), "missing cos() in:\n{code}");
    assert!(code.contains(".tan()"), "missing tan() in:\n{code}");
}

#[test]
fn codegen_multi_variable_structure_valid() {
    let ctx = Context::new();
    let x = ctx.symbol("x");
    let y = ctx.symbol("y");
    let z = ctx.symbol("z");
    let f = &x.powi(2) * &y + z.sin();
    let code = f.to_rust_fn("multi_var", &["x", "y", "z"]).unwrap();
    assert_valid_rust_structure(&code, "multi_var");
    assert!(
        code.contains("x: f64") && code.contains("y: f64") && code.contains("z: f64"),
        "missing three-parameter signature in:\n{code}"
    );
}

#[test]
fn codegen_nested_expression_balanced() {
    let ctx = Context::new();
    let x = ctx.symbol("x");
    // exp(sin(x^2)) + ln(cos(x) + 2)
    let f = x.powi(2).sin().exp() + (&x.cos() + 2).ln();
    let code = f.to_rust_fn("nested", &["x"]).unwrap();
    assert_valid_rust_structure(&code, "nested");
    assert!(code.contains(".exp()"), "missing exp() in:\n{code}");
    assert!(code.contains(".sin()"), "missing sin() in:\n{code}");
    assert!(code.contains(".ln()"), "missing ln() in:\n{code}");
}

#[test]
fn codegen_all_basic_functions_valid() {
    let ctx = Context::new();
    let x = ctx.symbol("x");
    // Chain several functions to stress-test codegen
    for (name, expr) in [
        ("gen_sqrt", x.sqrt()),
        ("gen_abs", x.abs()),
        ("gen_exp", x.exp()),
        ("gen_ln", x.ln()),
        ("gen_sin", x.sin()),
        ("gen_cos", x.cos()),
        ("gen_asin", x.asin()),
        ("gen_acos", x.acos()),
        ("gen_atan", x.atan()),
        ("gen_sinh", x.sinh()),
        ("gen_cosh", x.cosh()),
        ("gen_tanh", x.tanh()),
    ] {
        let code = expr
            .to_rust_fn(name, &["x"])
            .unwrap_or_else(|e| panic!("codegen failed for {name}: {e}"));
        assert_valid_rust_structure(&code, name);
    }
}