Region-based memory management

[ichiban]

Since we took advantage of Go's memory management, we have a lot of pointers and interfaces which are pointers disguised.

This also lets us provide an approachable set of APIs, I hope, but comes with a cost of GC because the GC has to trace all the live terms.

type Term interface {
	WriteTerm(w io.Writer, opts *WriteOptions, env *Env) error
	Compare(t Term, env *Env) int
}

We might be able to provide a workable set of APIs while implementing a WAM-like region-based memory management.

type VM struct {
	termCells []termCell
	// ...
}
type Term uint32 // index to termCells

Related issues:

• https://github.com/ichiban/prolog/issues/238
• https://github.com/ichiban/prolog/issues/226

Some articles that might be related:

• Flattening ASTs (and Other Compiler Data Structures)
• Handles are the better pointers