Limitations

This page exists so you do not discover these the hard way. Vow is pre-1.0.

Language

• No garbage collector, and no manual free() — arenas; the compiler works out when memory is no longer needed. Analysis is intraprocedural and conservative; escaping values live until the root arena is destroyed.
• No FFI — by design for v1 (FFI would punch a hole in the capability model).
• No async runtime — blocking I/O only.
• No SMT contract proving —requires/ensures are runtime checks only.
• Small surface — syntax and stdlib are still moving; do not assume every example on this site is in the shipped compiler the same day.

Tooling

• Compiler is Python + llvmlite (not self-hosted).
• vow fmt is a simple token formatter.
• No central package registry yet.

Security model caveats

• Capabilities protect stdlib effect entry points. A bug in the runtime C shim is still a bug.
• Granting a wide path (for example file-read:/) is still powerful — attenuation is your responsibility.

Source notes:docs/limitations.mdin the repo.