Trait Substitutable 

pub trait Substitutable {
    // Required methods
    fn subs(&self, old: &Expression, new: &Expression) -> Expression;
    fn subs_multiple(
        &self,
        substitutions: &[(Expression, Expression)],
    ) -> Expression;
}

Trait for types that support substitution operations

Required Methods

fn subs(&self, old: &Expression, new: &Expression) -> Expression

Substitute a single expression with another

Recursively walks the expression tree and replaces all occurrences of old with new. The replacement is structural - it compares expressions using PartialEq.

Arguments

• old - The expression to replace
• new - The expression to substitute in

Examples

use mathhook_core::prelude::*;
use mathhook_core::pattern::Substitutable;

let x = symbol!(x);
let expr = Expression::add(vec![
    Expression::symbol(x.clone()),
    Expression::integer(1)
]);

let result = expr.subs(&Expression::symbol(x.clone()), &Expression::integer(5));
let expected = Expression::add(vec![
    Expression::integer(5),
    Expression::integer(1)
]);

assert_eq!(result, expected);

fn subs_multiple( &self, substitutions: &[(Expression, Expression)], ) -> Expression

Apply multiple substitutions simultaneously

This is more efficient than chaining multiple subs() calls because it performs all substitutions in a single tree traversal.

Arguments

• substitutions - Slice of (old, new) expression pairs

Examples

use mathhook_core::prelude::*;
use mathhook_core::pattern::Substitutable;

let x = symbol!(x);
let y = symbol!(y);
let expr = Expression::add(vec![
    Expression::symbol(x.clone()),
    Expression::symbol(y.clone())
]);

let result = expr.subs_multiple(&[
    (Expression::symbol(x.clone()), Expression::integer(1)),
    (Expression::symbol(y.clone()), Expression::integer(2)),
]);

let expected = Expression::add(vec![
    Expression::integer(1),
    Expression::integer(2)
]);

assert_eq!(result, expected);

Implementors

impl Substitutable for Expression