feat(compiler): Add support for targeting WebAssembly.

The working principle is similar as before with x86, but instead of outputting .asm, it outputs .wat. This can be compiled into .wasm by using the wat2wasm assembler.

compiler/song_macros.go

@@ -0,0 +1,39 @@
+package compiler
+
+import (
+	"fmt"
+
+	"github.com/vsariola/sointu"
+)
+
+type SongMacros struct {
+	Song              *sointu.Song
+	VoiceTrackBitmask int
+	MaxSamples        int
+}
+
+func NewSongMacros(s *sointu.Song) *SongMacros {
+	maxSamples := s.SamplesPerRow() * s.TotalRows()
+	p := SongMacros{Song: s, MaxSamples: maxSamples}
+	trackVoiceNumber := 0
+	for _, t := range s.Tracks {
+		for b := 0; b < t.NumVoices-1; b++ {
+			p.VoiceTrackBitmask += 1 << trackVoiceNumber
+			trackVoiceNumber++
+		}
+		trackVoiceNumber++ // set all bits except last one
+	}
+	return &p
+}
+
+func (p *SongMacros) NumDelayLines() string {
+	total := 0
+	for _, instr := range p.Song.Patch.Instruments {
+		for _, unit := range instr.Units {
+			if unit.Type == "delay" {
+				total += unit.Parameters["count"] * (1 + unit.Parameters["stereo"])
+			}
+		}
+	}
+	return fmt.Sprintf("%v", total)
+}