Module display 

Display Trait Implementations for AST (Plain Text)

This module provides std::fmt::Display implementations for all AST types, converting them back to plain text mathematical notation.

Design Philosophy

• Minimal Parentheses: Use operator precedence to minimize parenthesization
• Readable Output: Generate human-readable plain text
• Round-trip Capable: Output can be parsed back (though not guaranteed identical AST)

Precedence Levels

1. Addition, Subtraction: precedence = 1
2. Multiplication, Division, Modulo: precedence = 2
3. Exponentiation: precedence = 3
4. Unary operations: precedence = 4 (implicit, highest)

Examples

use mathlex::ast::{Expression, BinaryOp};

// 2 + 3 * 4 → "2 + 3 * 4" (no parens needed)
let expr = Expression::Binary {
    op: BinaryOp::Add,
    left: Box::new(Expression::Integer(2)),
    right: Box::new(Expression::Binary {
        op: BinaryOp::Mul,
        left: Box::new(Expression::Integer(3)),
        right: Box::new(Expression::Integer(4)),
    }),
};
assert_eq!(format!("{}", expr), "2 + 3 * 4");