func Delta(name string) DeltaID {
	if internal.Running {
		setErr(errors.New("input delta declaration: declarations must happen before starting the framework"))
		return noDelta
	}
	_, ok := actions.name[name]
	if ok {
		setErr(errors.New("input delta declaration: name already taken by another action"))
		return noDelta
	}
	a := len(deltas.name)
	if a >= maxID {
		setErr(errors.New("input delta declaration: too many delta actions"))
		return noDelta
	}
	actions.name[name] = DeltaID(a)
	actions.list = append(actions.list, DeltaID(a))
	deltas.name = append(deltas.name, name)
	return DeltaID(a)
}
//////////////////////////////////////////////////////////////////////////////
Delta declares a new delta action, and returns its ID.
package input
import (
	"errors"
	"github.com/cozely/cozely/coord"
	"github.com/cozely/cozely/internal"
)
type DeltaID uint32
const noDelta = DeltaID(maxID)
var deltas struct {
	name []string
}
type delta struct {
	value    coord.XY
	previous coord.XY
}