Function generate 

pub fn generate(spec: &Spec, opts: &GoOptions) -> String

Turn a spec into a Go source file declaring its parse tables.

This does not check the spec: it cannot fail, so a spec with both unknown_env and a mount is emitted with a parser that refuses the mounted commands’ variables. generate_with_types refuses that combination and is what usage generate go calls. Returning a Result here waits for v8; see V8.md.