melrōse musical expression player

package core import ( "fmt" "github.com/emicklei/melrose/notify" ) type ChordProgression struct { root HasValue sequence HasValue } func NewChordProgression(root, sequence HasValue) ChordProgression { return ChordProgression{root: root, sequence: sequence} } // Replaced is part of Replaceable func (c ChordProgression) Replaced(from, to Sequenceable) Sequenceable { if IsIdenticalTo(from, c) { return to } return c } // Storex is part of Storable func (c ChordProgression) Storex() string { return fmt.Sprintf("progression(%s,%s)", Storex(c.root), Storex(c.sequence)) } // S is part of Sequenceable func (c ChordProgression) S() Sequence { chords := c.C() j := EmptySequence for _, each := range chords { j = j.SequenceJoin(each.S()) } return j } var noChords = []Chord{} func (c ChordProgression) C() []Chord { cs, ok := c.root.Value().(string) if !ok { notify.Warnf("chord progression root must be string, type: %T", c.root.Value()) return noChords } sc, err := ParseScale(cs) if err != nil { notify.Warnf("chord progression root must use scale notation, error: %v", err) return noChords } input, ok := c.sequence.Value().(string) if !ok { notify.Warnf("chord progression must be string, type: %T", c.sequence.Value()) return noChords } p := newFormatParser(input) chords, err := p.parseChordProgression(sc) if err != nil { notify.Warnf("parsing progression failed, error: %v", err) return noChords } return chords }