Memory Management

Frost combines manual memory management with modern safety features to provide developers with fine-grained control while minimizing the risk of memory-related errors.

The defer Keyword

One of Frost's key memory management features is the defer keyword, which ensures that cleanup code is executed when leaving the current scope:

import "https://frost-lang.deno.dev/std/lib.ff"

main: never -> int = {
    buffer: *byte = malloc(1024)
    defer free(buffer)

    % Use buffer...

    0
} % buffer is automatically freed here

The defer keyword offers several advantages:

1. Predictable Cleanup: Cleanup code is placed near the allocation, improving readability.

2. Error-Resistant: Deferred actions are executed even if an error occurs, preventing resource leaks.

3. Nested Deferral: Multiple defer statements are executed in reverse order of declaration.

LLVM Sanitizers

Frost leverages LLVM's powerful sanitizers to catch memory errors at runtime:

1. AddressSanitizer (ASan): Detects out-of-bounds accesses, use-after-free, and memory leaks.

2. MemorySanitizer (MSan): Finds uses of uninitialized memory.

3. UndefinedBehaviorSanitizer (UBSan): Catches undefined behavior like integer overflow.

Safe Abstractions

Frost provides safe abstractions over raw pointers:

% Array bounds checking
arr: [10]int = [1 2 3 4 5 6 7 8 9 10]
value: int = arr.#5 % Safe access

% Null pointer checks
if not ptr {
    printf("Null pointer detected\n")
}

Best Practices

1. Use defer for all resource cleanup.

2. Leverage LLVM sanitizers during development and testing.

3. Implement custom destructors for complex types to ensure proper cleanup.

By combining these features, Frost provides a memory management model that is both powerful and safe, allowing developers to write efficient systems code with confidence.