repl

type Host interface {
	// EvalContext returns the parent eval context for evaluating src, plus a
	// finish func run when that input's evaluation completes (e.g. to end a trace
	// span). finish may be nil. The Session layers session bindings (_, _N, and
	// named bindings) as a child of parent before evaluating. ctx is tied to the
	// session lifetime (cancelled on exit / SIGTERM) and is suitable as a span
	// parent.
	EvalContext(ctx context.Context, src string) (parent *hcl.EvalContext, finish func(), err error)

	// CompletionContext returns the context whose variables and functions are the
	// tab-completion candidates. It should be cheap and side-effect-free (no trace
	// spans): it is called per keystroke. It typically returns the same
	// variables/functions a user can reference, including any per-eval "ctx".
	CompletionContext(ctx context.Context) (*hcl.EvalContext, error)

	// Reserved reports whether name may not be bound as a session variable. The
	// Session already reserves "_" and the numbered "_N"; a host adds its own
	// (e.g. "ctx" and built-in top-level namespaces).
	Reserved(name string) bool
}

type MetaCommand struct {
	Names   []string
	Summary string // shown in :help
	Run     func(args []string, errOut io.Writer) (exit bool)
}

type Options struct {
	// Banner is printed once at startup, before a generic usage hint. Empty
	// prints only the hint.
	Banner string

	// HistoryPath is the readline history file; "" disables persistence.
	HistoryPath string

	// Meta are additional meta-commands (e.g. log control) beyond the built-ins.
	Meta []MetaCommand

	// OnStart is invoked once after the line editor is live, with the editor's
	// redraw-aware writer. A host can point its async log output there so writes
	// erase and redraw the prompt cleanly. Nil if unused.
	OnStart func(refresh io.Writer)

	// OnDetach is invoked once during teardown, before the editor is closed, so a
	// host can repoint async output away from the (about-to-close) editor writer.
	OnDetach func()

	// Out and ErrOut override the result and diagnostic streams (used by tests).
	// When nil they default to the editor's stdout and os.Stderr.
	Out    io.Writer
	ErrOut io.Writer
}

type Session struct {
	// contains filtered or unexported fields
}