Song accidentals

garden · Mar 10, 2016 · b56ff60 · b56ff60
1 parent 064af5b
commit b56ff60
Showing 1 changed file with 28 additions and 11 deletions.
diff --git a/lib/midi/song.js b/lib/midi/song.js
@@ -72,7 +72,11 @@ var parseAbc = function(text) {
 // Tokenizer states.
 var tstate = {
   main: function(tok, c) {
-    if (isNote(c)) {
+    if (isAccidental(c)) {
+      tok.startToken();
+      return tstate.accidental;
+    } if (isNote(c)) {
+      tok.startToken();
       return tstate.letter;
     } else if (c === undefined) {
       return tstate.end;
@@ -81,11 +85,20 @@ var tstate = {
   end: function(tok, c) {},
 
   // A note has the following elements:
-  // letter [octave] [duration].
+  // [accidental] letter [octave] [duration].
+
+  accidental: function(tok, c) {
+    if (isNote(c)) {
+      return tstate.letter;
+    } else if (c === '^') {
+      tok.accidental++;
+    } else if (c === '_') {
+      tok.accidental--;
+    }
+  },
 
   // We are on a letter.
   letter: function(tok, c) {
-    tok.startToken();
     tok.note = tok.char().charCodeAt(0);
     if (tok.note >= 97) {  // Higher-pitched (a-g instead of A-G).
       tok.note -= 32;  // Convert to A-G.
@@ -113,7 +126,7 @@ var tstate = {
     var slash = (c === '/');
     var number = /^[0-9]$/.test(c);
     if (number || slash) {
-      tok.numStart = tok.i;
+      tok.spanStart = tok.i;
       tok.char();
       if (number) {
         return tstate.durNum;
@@ -128,7 +141,7 @@ var tstate = {
   durNum: function(tok, c) {
     var number = /^[0-9]$/.test(c);
     if (!number) {
-      var num = tok.text.slice(tok.numStart, tok.i);
+      var num = tok.text.slice(tok.spanStart, tok.i);
       tok.durNum = +num;
       if (c === '/') {
         tok.char();
@@ -144,7 +157,7 @@ var tstate = {
     var slash = (c === '/');
     var number = /^[0-9]$/.test(c);
     if (number) {
-      tok.numStart = tok.i;
+      tok.spanStart = tok.i;
       tok.char();
       return tstate.durDenom;
     } else if (slash) {
@@ -159,7 +172,7 @@ var tstate = {
   durSlashes: function(tok, c) {
     var slash = (c === '/');
     if (!slash) {
-      var slashes = tok.i - tok.numStart;
+      var slashes = tok.i - tok.spanStart;
       tok.durDenom = (1 << slashes);
       return tstate.mkNote;
     }
@@ -168,15 +181,15 @@ var tstate = {
   durDenom: function(tok, c) {
     var number = /^[0-9]$/.test(c);
     if (!number) {
-      var num = tok.text.slice(tok.numStart, tok.i);
+      var num = tok.text.slice(tok.spanStart, tok.i);
       tok.durDenom = +num;
       return tstate.mkNote;
     }
   },
 
   mkNote: function(tok, c) {
     var dur = tok.durNum / tok.durDenom;
-    var note = tok.note + tok.octave * 12;
+    var note = tok.note + tok.octave * 12 + tok.accidental;
     tok.addNote(note, dur);
     return tstate.main;
   },
@@ -195,7 +208,8 @@ var Tokenizer = function(text) {
   this.note = undefined;
   this.octave = 0;
   this.noteStart = 0;
-  this.numStart = 0;
+  this.spanStart = 0;
+  this.accidental = 0;
   this.durNum = 1;
   this.durDenom = 1;
   this.noteDur = 0.4;
@@ -212,7 +226,8 @@ Tokenizer.prototype = {
   note: undefined,  // MIDI note number between A-G.
   octave: 0,
   noteStart: 0,  // Time since the start of the song.
-  numStart: 0,   // Position in the text string.
+  spanStart: 0,  // Position in the text string.
+  accidental: 0, // Sharp / flat note change.
   durNum: 1,     // Note duration numerator / denominator.
   durDenom: 1,
   noteDur: 0.5,  // Note duration.
@@ -254,6 +269,7 @@ Tokenizer.prototype = {
     this.noteStart += dur * this.noteDur;
     this.token(noteOffEvent(note, this.noteStart + this.noteOverlay));
     this.octave = 0;
+    this.accidental = 0;
     this.durNum = 1;
     this.durDenom = 1;
     this.noteDur = 0.4;
@@ -262,6 +278,7 @@ Tokenizer.prototype = {
 };
 
 var isNote = function(c) { return /^[a-gA-G]$/.test(c); };
+var isAccidental = function(c) { return /^[\^_=]$/.test(c); };
 var isSilence = function(c) { return /^[zZ]$/.test(c); };
 
 var noteOnEvent = function(note, start) {