query

type Collation int

type ErrUnsupportedCollation struct {
	Collation Collation
}

type Iterator interface {
	// Next advances the iterator to the next value, which will then be available through
	// the Result method. It returns false if no further advancement is possible, or if an
	// error was encountered during iteration.  Err should be consulted to distinguish
	// between the two cases.
	Next(ctx context.Context) bool
	// Results returns the current result. The type depends on the collation mode of the query.
	Result() interface{}
	// Err returns any error that was encountered by the Iterator.
	Err() error
	// Close the iterator and do internal cleanup.
	Close() error
}

type Language struct {
	Name    string
	Session func(graph.QuadStore) Session

	HTTPQuery func(ctx context.Context, qs graph.QuadStore, w ResponseWriter, r io.Reader)
	HTTPError func(w ResponseWriter, err error)
}

type Options struct {
	Limit     int
	Collation Collation
}

type REPLSession = Session

type ResponseWriter interface {
	Write([]byte) (int, error)
	WriteHeader(int)
}

type Session interface {
	// Execute runs the query and returns an iterator over the results.
	// Type of results depends on Collation. See Options for details.
	Execute(ctx context.Context, query string, opt Options) (Iterator, error)
}