Defer & scope cleanup

Registration

defer registers a call or a brace block for normal scope exit. It does not require a hidden heap-allocated closure.

Block form

defer {
    FlushMetrics();
    ReleaseScratch();
}

This fragment assumes the cleanup operations exist. It illustrates a scope-bound sequence rather than an immediately executed block.

Normal exits

A value-producing block's break Value; is a normal exit and runs applicable deferred cleanup. Deferred work and object cleanup follow their documented reverse registration and lifetime order.

Fatal termination

Panic and fatal traps skip cleanup. Sn's design does not supply exception-style unwinding. Use recoverable result paths when normal cleanup and error reporting are required.