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// Example case from the 05/02/2025 Conjure VIP meeting
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use tree_morph::{helpers::select_panic, prelude::*};

            

        

            

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use uniplate::Uniplate;

            

        

            

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#[derive(Debug, Clone, PartialEq, Eq, Uniplate)]

            

        

            

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#[uniplate()]

            

        

            

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enum Shape {

            

        

            

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    Circle(Box<Shape>),

            

        

            

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    Square,

            

        

            

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    Triangle,

            

        

            

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}

            

        

            

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// O(/\) ~> /\

            

        

            

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fn circ_tri_to_tri(_: &mut Commands<Shape, ()>, expr: &Shape, _: &()) -> Option<Shape> {

            

        

            

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    if let Shape::Circle(inner) = expr

            

        

            

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        && let Shape::Triangle = **inner

            

        

            

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    {

            

        

            

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        return Some(Shape::Triangle);

            

        

            

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    }

            

        

            

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    None

            

        

            

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}

            

        

            

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// O(O(/\)) ~> []

            

        

            

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fn circ_circ_tri_to_sqr(_: &mut Commands<Shape, ()>, expr: &Shape, _: &()) -> Option<Shape> {

            

        

            

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    if let Shape::Circle(inner) = expr

            

        

            

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        && let Shape::Circle(inner_inner) = inner.as_ref()

            

        

            

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        && let Shape::Triangle = **inner_inner

            

        

            

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    {

            

        

            

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        return Some(Shape::Square);

            

        

            

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    }

            

        

            

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    None

            

        

            

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}

            

        

            

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#[test]

            

        

            

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fn circ_tri() {

            

        

            

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    // O(/\)

            

        

            

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    let expr = Shape::Circle(Box::new(Shape::Triangle));

            

        

            

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    let engine = EngineBuilder::new()

            

        

            

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        .add_rule(circ_tri_to_tri as RuleFn<_, _>)

            

        

            

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        .add_rule(circ_circ_tri_to_sqr as RuleFn<_, _>)

            

        

            

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        .build();

            

        

            

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    let (result, _) = engine.morph(expr, ());

            

        

            

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    assert_eq!(result, Shape::Triangle);

            

        

            

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}

            

        

            

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#[test]

            

        

            

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fn circ_circ_tri() {

            

        

            

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    // O(O(/\))

            

        

            

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    let expr = Shape::Circle(Box::new(Shape::Circle(Box::new(Shape::Triangle))));

            

        

            

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    // Same priority group - 2nd rule applies first as it applies higher in the tree

            

        

            

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    let engine = EngineBuilder::new()

            

        

            

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        .add_rule_group(rule_fns![circ_tri_to_tri, circ_circ_tri_to_sqr])

            

        

            

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        .build();

            

        

            

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    let (result, _) = engine.morph(expr, ());

            

        

            

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    assert_eq!(result, Shape::Square);

            

        

            

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}

            

        

            

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#[test]

            

        

            

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fn shape_higher_priority() {

            

        

            

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    // O(O(/\))

            

        

            

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    let expr = Shape::Circle(Box::new(Shape::Circle(Box::new(Shape::Triangle))));

            

        

            

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    // Higher priority group - 1st rule applies first even though it applies lower in the tree

            

        

            

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    let engine = EngineBuilder::new()

            

        

            

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        .add_rule(circ_tri_to_tri as RuleFn<_, _>)

            

        

            

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        .add_rule(circ_circ_tri_to_sqr as RuleFn<_, _>)

            

        

            

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        .build();

            

        

            

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    let (result, _) = engine.morph(expr, ());

            

        

            

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    // O(O(/\)) ~> O(/\) ~> /\

            

        

            

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    assert_eq!(result, Shape::Triangle);

            

        

            

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}

            

        

            

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#[should_panic]

            

        

            

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#[test]

            

        

            

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fn shape_multiple_rules_panic() {

            

        

            

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    // O(O(/\))

            

        

            

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    let expr = Shape::Circle(Box::new(Shape::Circle(Box::new(Shape::Triangle))));

            

        

            

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    // Same rule twice, applicable at the same time

            

        

            

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    let engine = EngineBuilder::new()

            

        

            

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        .set_selector(select_panic)

            

        

            

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        .add_rule_group(rule_fns![circ_tri_to_tri, circ_tri_to_tri])

            

        

            

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        .build();

            

        

            

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    engine.morph(expr, ());

            

        

            

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}