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Enums & Pattern Matching

● STABLE(Algebraic enum data types, payload variants, and structural pattern matching expressions)

AdeshLang enums are algebraic data types that can represent simple discrete options or carry associated payload data per variant. Pattern matching (match) safely destructures enum values at compile time.

1. Algebraic Enums & Structural Pattern Matching​

Variants within an enum can be unit variants (no payload) or tuple-like payload variants containing data values.

Code Example​

// Enum definition with payload variants
enum ConnectionState {
    Disconnected,
    Connecting(string),
    Connected(string, i32), // host, port
    Failed(i32, string)     // error_code, reason
}

fn describeState(state) {
    match state {
        ConnectionState.Disconnected => {
            print("State: Disconnected");
        },
        ConnectionState.Connecting(url) => {
            print("State: Connecting to URL:", url);
        },
        ConnectionState.Connected(host, port) => {
            print("State: Connected to", host, "on port", port);
        },
        ConnectionState.Failed(code, msg) => {
            print("State: Connection failed [", code, "]:", msg);
        }
    }
}

let s1 = ConnectionState.Connecting("https://api.adeshlang.org");
let s2 = ConnectionState.Connected("192.168.1.100", 443);
let s3 = ConnectionState.Failed(404, "Server Endpoint Not Found");

describeState(s1);
describeState(s2);
describeState(s3);

Terminal Output​

State: Connecting to URL: https://api.adeshlang.org
State: Connected to 192.168.1.100 on port 443
State: Connection failed [ 404 ]: Server Endpoint Not Found

Breakdown​

  • enum Name { Variant1, Variant2(Type) }: Defines algebraic type variants.
  • match target { Variant(bindings) => body }: Structural pattern matching that automatically binds variables to payload arguments.