melrōse musical expression player

package core import ( "fmt" ) const ( // OnceFromTo "once" OnceFromTo = iota // OnceFromToFrom "once-two-way" OnceFromToFrom // RepeatFromTo "repeat" RepeatFromTo // RepeatFromToFrom "repeat-two-way" RepeatFromToFrom ) // Interval is a HasValue that has a Value between [from..to] and increments with [by]. // If the end of the interval is reached then the Value is set to [from]. // The fields of an Interval are also HasValue. type Interval struct { from HasValue to HasValue by HasValue strategy intervalStrategy value int } func (i *Interval) Value() any { return i.value } // Next returns and increases its value with [by]. func (i *Interval) Next() any { by := Int(i.by) next := i.value + by if by < 0 { if next < Int(i.from) { i.value = Int(i.to) return i.value } } if by > 0 { if next > Int(i.to) { i.value = Int(i.from) return i.value } } i.value = next return i.value } // NewInterval creates new Interval. The initial Value is set to [from]. Specify the repeat strategy. func NewInterval(from, to, by HasValue, strategy int) *Interval { start := Int(from) return &Interval{from: from, to: to, by: by, value: start, strategy: asIntervalStrategy(strategy)} } // Storex is part of Storable. func (i Interval) Storex() string { if i.strategy.id() == OnceFromTo { return fmt.Sprintf("interval(%v,%v,%v)", Storex(i.from), Storex(i.to), Storex(i.by)) } name := intervalStrategyName(i.strategy.id()) return fmt.Sprintf("interval(%s,%s,%s,'%s')", Storex(i.from), Storex(i.to), Storex(i.by), name) } // Inpsect is part of Inspectable func (i Interval) Inspect(n Inspection) { n.Properties["value"] = i.Value() n.Properties["length"] = (Int(i.to)-Int(i.from))/Int(i.by) + 1 } // ParseIntervalStrategy return the non-exposed strategy based on the name. If unknown then return OnceFromTo ("once"). func ParseIntervalStrategy(s string) intervalStrategy { if is, ok := intervalStrategies[s]; ok { return is } return strategyOnceFromTo{} } func intervalStrategyName(i int) string { for name, each := range intervalStrategies { if each.id() == i { return name } } return "?" } func asIntervalStrategy(i int) intervalStrategy { for _, each := range intervalStrategies { if each.id() == i { return each } } return strategyOnceFromTo{} } type intervalStrategy interface { id() int //reachedTo(i *Interval) //reachedFrom(i *Interval) } var intervalStrategies = map[string]intervalStrategy{ "once": strategyOnceFromTo{}, "repeat": strategyRepeatFromTo{}, "two-way": strategyOnceFromToFrom{}, "repeat-two-way": strategyRepeatFromToFrom{}, } type strategyOnceFromTo struct{} func (s strategyOnceFromTo) id() int { return OnceFromTo } type strategyRepeatFromTo struct{} func (s strategyRepeatFromTo) id() int { return RepeatFromTo } type strategyOnceFromToFrom struct{} func (s strategyOnceFromToFrom) id() int { return OnceFromToFrom } type strategyRepeatFromToFrom struct{} func (s strategyRepeatFromToFrom) id() int { return RepeatFromToFrom }