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abstract

The abstract keyword marks a type or member as abstract: it declares a shape without a complete implementation. Abstract types cannot be instantiated directly and abstract members must be implemented by a concrete subtype.

Syntax & Example​

abstract interface Shape {
    fn area(): f64;
}

struct Circle(radius: f64): Shape {
    pub fn area(): f64 {
        return 3.14159 * self.radius * self.radius;
    }
}

Use Cases​

  • Defining base interfaces or classes that only describe behavior.
  • Forcing subtypes to provide concrete implementations of specific members.
  • Building shared contracts across a family of related types.
note

abstract is reserved by the lexer. Parser support is focused on interface/type declarations; treat partial forms as experimental.