pathmod_core crate

Purpose

• Core runtime for Pathmod. Provides the Accessor<T, F> type and its safe methods for reading/mutating focused fields.
• Used indirectly by most users via the re-export crate pathmod, but library authors may depend directly if they need only the runtime.

What is Accessor?

• A tiny, Copy value that stores the byte offset from &T to &F.
• Operations:
  • get(&T) -> &F
  • get_mut(&mut T) -> &mut F
  • set(&mut T, F)
  • set_mut(&mut T, impl FnOnce(&mut F))
  • set_clone(&mut T, &F) where F: Clone (MVP semantics: only the leaf value is cloned)
  • compose(self, Accessor<F, V>) -> Accessor<T, V>
• Representation: offset-based; composition is O(1) addition of offsets. Public API is safe; unsafe is encapsulated inside.

Construction

• Usually constructed by the derive macro from pathmod_derive (via #[derive(Accessor)]).
• Also provides:
  • const unsafe fn from_offset(isize) for macro/const construction.
  • fn from_fns(get_ref, get_mut) for runtime construction (computes offset safely without dereferencing).

When should I depend on this crate directly?

• If you are building your own derive/projection utilities or want to avoid a proc-macro dependency and construct accessors at runtime.
• Otherwise, prefer pathmod which re-exports everything.

MSRV

• Intended MSRV 1.89+ (matches usage of core::mem::offset_of! in the derive crate).

License Dual-licensed under MIT or Apache-2.0.