Boolean and Field Types

Boolean

The Boolean type is a primitive type with only two values: true and false. Value bindings like these live inside circuits:

export pure circuit flags(): Boolean {
    const isActive: Boolean = true;
    const isComplete: Boolean = false;
    return isActive && !isComplete;
}

Boolean Operations

Compact supports standard boolean operators:

export pure circuit logic(a: Boolean, b: Boolean): Boolean {
    // Logical AND
    const both = a && b;

    // Logical OR
    const either = a || b;

    // Logical NOT
    const opposite = !a;

    return both || either || opposite;
}

Note: The boolean operators &&, ||, ! follow standard semantics. The && and || operators use short-circuit evaluation.

Boolean in Conditionals

Booleans are used in if statements and conditional expressions:

export pure circuit choose(
    condition: Boolean,
    valueIfTrue: Field,
    valueIfFalse: Field
): Field {
    if (condition) {
        // do something
    }

    // Conditional expression: e0 ? e1 : e2 where e0 is Boolean
    const result = condition ? valueIfTrue : valueIfFalse;
    return result;
}

Field

The Field type is “the type of elements in the scalar prime field of the zero-knowledge proving system.”

export pure circuit fieldExample(): Field {
    const x: Field = 42;
    return x;
}

Converting to Field

Casting from Uint<0..m> to Field is a static cast (allowed, no runtime cost):

export pure circuit toField(): Field {
    const amount: Uint<64> = 100;
    const amountAsField = amount as Field;
    return amountAsField;
}

When to Use Field vs Uint

Note: The following is usage guidance for this tutorial, not official documentation.

Exercises

Complete the exercises in exercises/02_types/01_boolean/ and exercises/02_types/04_field/.