style: add comments to the public methods and members in the root package.

score.go

@@ -1,11 +1,16 @@
 package sointu
 
+// Score represents the arrangement of notes in a song; just a list of tracks
+// and RowsPerPattern and Length (in patterns) to know the desired length of a
+// song in rows. If any of the tracks is too short, all the notes outside the
+// range should be just considered as holding the last note.
 type Score struct {
 	Tracks         []Track
-	RowsPerPattern int
+	RowsPerPattern int // number of rows in each pattern
 	Length         int // length of the song, in number of patterns
 }
 
+// Copy makes a deep copy of a Score.
 func (l Score) Copy() Score {
 	tracks := make([]Track, len(l.Tracks))
 	for i, t := range l.Tracks {
@@ -14,6 +19,8 @@ func (l Score) Copy() Score {
 	return Score{Tracks: tracks, RowsPerPattern: l.RowsPerPattern, Length: l.Length}
 }
 
+// NumVoices returns the total number of voices used in the Score; summing the
+// voices of every track
 func (l Score) NumVoices() int {
 	ret := 0
 	for _, t := range l.Tracks {
@@ -22,6 +29,11 @@ func (l Score) NumVoices() int {
 	return ret
 }
 
+// FirstVoiceForTrack returns the index of the first voice of given track. For
+// example, if the Score has three tracks (0, 1 and 2), with 1, 3, 2 voices,
+// respectively, then FirstVoiceForTrack(0) returns 0, FirstVoiceForTrack(1)
+// returns 1 and FirstVoiceForTrack(2) returns 4. Essentially computes just the
+// cumulative sum.
 func (l Score) FirstVoiceForTrack(track int) int {
 	ret := 0
 	for _, t := range l.Tracks[:track] {
@@ -30,6 +42,8 @@ func (l Score) FirstVoiceForTrack(track int) int {
 	return ret
 }
 
+// LengthInRows returns just RowsPerPattern * Length, as the length is the
+// length in the number of patterns.
 func (l Score) LengthInRows() int {
 	return l.RowsPerPattern * l.Length
 }