formulac 0.8.0

A complex-number and extensible function supported math expression parser for 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

//! # astnode/compile.rs
//!
//! Compiles an [`AstNode`] tree into a flat sequence of postfix [`Token`]s
//! (Reverse Polish Notation) for stack-based evaluation.
//!
//! ## Entry point
//! [`AstNode::compile`] performs a depth-first traversal of the AST
//! and emits tokens in evaluation order.
//! The resulting token sequence is consumed by the executor in [`builder`].

use crate::astnode::AstNode;
use crate::core::Real;
use crate::token::Token;

impl<T: Real> AstNode<T> {
    /// Compiles the AST into a flat sequence of postfix `Token`s.
    pub(crate) fn compile(&self) -> Vec<Token<T>> {
        let mut out = Vec::new();
        self.compile_into(&mut out);
        out
    }

    fn compile_into(&self, out: &mut Vec<Token<T>>) {
        match self {
            Self::Number { value, span } => out.push(Token::Number { value: value.clone(), span: *span }),
            Self::Argument { index, span } => out.push(Token::Argument { index: *index, span: *span }),
            Self::UnaryOperator { kind, expr, span } => {
                expr.compile_into(out);
                out.push(Token::UnaryOperator { kind: *kind, span: *span });
            }
            Self::BinaryOperator { kind, left, right, span } => {
                left.compile_into(out);
                right.compile_into(out);
                out.push(Token::BinaryOperator { kind: *kind, span: *span });
            }
            Self::FunctionCall { kind, args, span } => {
                for arg in args { arg.compile_into(out); }
                out.push(Token::Function { kind: *kind, span: *span });
            }
            Self::UserFunctionCall { func, args, span } => {
                for arg in args { arg.compile_into(out); }
                out.push(Token::UserFunction { func: func.clone(), span: *span });
            }
            Self::Derivative { .. } => {
                unreachable!("Derivative nodes must be resolved before compile()")
            }
        }
    }
}

#[cfg(test)]
mod astnode_tests {
    use super::*;
    use crate::functions::FunctionKind;
    use crate::operators::{
        BinaryOperatorKind,
        UnaryOperatorKind,
    };
    use crate::lexer::Span;
    use num_complex::Complex;

    #[test]
    fn test_compile_number() {
        let ast = AstNode::Number { value: Complex::new(1.0, 0.0), span: Span::from(0..1) };
        let tokens = ast.compile();
        assert_eq!(tokens, vec![Token::Number { value: Complex::new(1.0, 0.0), span: Span::from(0..1) }]);
    }

    #[test]
    fn test_compile_argument() {
        let ast = AstNode::<f64>::Argument { index: 1, span: Span::from(0..1) };
        let tokens = ast.compile();
        assert_eq!(tokens, vec![Token::Argument { index: 1, span: Span::from(0..1) }]);
    }

    #[test]
    fn test_compile_unary_operator() {
        let ast = -AstNode::Number { value: Complex::new(1.0, 0.0), span: Span::from(2..3) };
        let tokens = ast.compile();
        assert_eq!(
            tokens,
            vec![Token::Number { value: Complex::new(1.0, 0.0), span: Span::from(2..3) }, Token::UnaryOperator { kind: UnaryOperatorKind::Negative, span: Span::from(2..3) }]
        );
    }

    #[test]
    fn test_compile_binary_operator() {
        let ast = AstNode::Number { value: Complex::new(1.0, 0.0), span: Span::from(0..1) } + AstNode::Argument { index: 1, span: Span::from(4..5) };
        let tokens = ast.compile();
        assert_eq!(
            tokens,
            vec![
                Token::Number { value: Complex::new(1.0, 0.0), span: Span::from(0..1) },
                Token::Argument { index: 1, span: Span::from(4..5) },
                Token::BinaryOperator { kind: BinaryOperatorKind::Add, span: Span::from(0..1) },
            ]
        );
    }

    #[test]
    fn test_compile_function_single_argument() {
        let ast = AstNode::Number { value: Complex::new(1.0, 0.0), span: Span::from(0..1) }.sin();
        let tokens = ast.compile();
        assert_eq!(tokens, vec![Token::Number { value: Complex::new(1.0, 0.0), span: Span::from(0..1) }, Token::Function { kind: FunctionKind::Sin, span: Span::from(0..1) }]);
    }

    #[test]
    fn test_compile_function_multi_arguments() {
        let ast = AstNode::Number { value: Complex::new(2.0, 0.0), span: Span::from(0..1) }.pow(AstNode::Argument { index: 0, span: Span::from(4..5) });
        let tokens = ast.compile();
        assert_eq!(
            tokens,
            vec![
                Token::Number { value: Complex::new(2.0, 0.0), span: Span::from(0..1) },
                Token::Argument { index: 0, span: Span::from(4..5) },
                Token::Function { kind: FunctionKind::Pow, span: Span::from(0..1) },
            ]
        );
    }

    #[test]
    fn test_compile_nested_expression() {
        // cos(1 + 2)
        let ast = (AstNode::Number { value: Complex::new(1.0, 0.0), span: Span::from(0..1) } + AstNode::Number { value: Complex::new(2.0, 0.0), span: Span::from(4..5) }).cos();
        let tokens = ast.compile();
        assert_eq!(
            tokens,
            vec![
                Token::Number { value: Complex::new(1.0, 0.0), span: Span::from(0..1) },
                Token::Number { value: Complex::new(2.0, 0.0), span: Span::from(4..5) },
                Token::BinaryOperator { kind: BinaryOperatorKind::Add, span: Span::from(0..1) },
                Token::Function { kind: FunctionKind::Cos, span: Span::from(0..1) },
            ]
        );
    }
}