Why pure Go

go-ruby-ipaddr/ipaddr reimplements Ruby's IPAddr in pure Go, with cgo disabled. The slice of Ruby it covers is deterministic and interpreter-independent: given its inputs, the result is a pure function of those inputs — no live binding, no evaluation of arbitrary Ruby. That is exactly the part that can — and should — live as a standalone Go library, separate from the interpreter.

Bound by rbgo, reusable by anyone

This library is bound into go-embedded-ruby's rbgo as a native module — the same pattern as go-ruby-regexp and go-ruby-erb — so that:

• any Go program can import github.com/go-ruby-ipaddr/ipaddr directly, with no Ruby runtime;
• the dependency runs the other way — rbgo binds this module, rather than this module depending on the interpreter;
• the behaviour is pinned by a differential oracle against the system ruby, independent of any one consumer.

Why pure Go matters here

Because the library is CGO-free and dependency-free, it:

• cross-compiles to every Go target with no C toolchain, and links into a single static binary;
• has no dependency on the Ruby runtime — the dependency runs the other way;
• can be differentially tested against the ruby binary wherever one is on PATH, while the cross-arch lanes (where ruby is absent) still validate the library itself.

See Usage & API for the surface and Roadmap for what is in scope.