From 0935f2fe2864198723356a2fa8ff1b0a57e56876 Mon Sep 17 00:00:00 2001
From: Jules Laplace <jules@okfoc.us>
Date: Tue, 20 Sep 2016 13:31:55 -0400
Subject: parsing scl files

---
 index.html    | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 intonation.js | 51 ++++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 105 insertions(+), 1 deletion(-)

diff --git a/index.html b/index.html
index 2bfc678..fc82edb 100644
--- a/index.html
+++ b/index.html
@@ -11,6 +11,47 @@ pre {
   white-space: pre-line;
 }
 </style>
+
+<script type="text/scale" id="meantone-scl">
+! meanquar.scl
+!
+1/4-comma meantone scale. Pietro Aaron's temperament (1523)
+ 12
+!
+ 76.04900
+ 193.15686
+ 310.26471
+ 5/4
+ 503.42157
+ 579.47057
+ 696.57843
+ 25/16
+ 889.73529
+ 1006.84314
+ 1082.89214
+ 2/1
+</script>
+
+<script type="text/scale" id="twelveet-scl">
+! 12et.scl
+!
+12 equal temperament
+ 12
+!
+ 100.
+ 200.
+ 300.
+ 400.
+ 500.
+ 600.
+ 700.
+ 800.
+ 900.
+ 1000.
+ 1100.
+ 1200.
+</script>
+
 <pre>
 <script src="intonation.js"></script>
 <script>
@@ -46,6 +87,13 @@ write("12-tet")
 write( s.range(0, 13).map(function(i){ return i.toFixed(0) }).join(delim) )
 write("")
 
+s = new Intonation({
+  scl: document.querySelector("#twelveet-scl").innerHTML
+})
+write("12-tet.scl:")
+write( s.range(0, s.scale.length+1).map(function(i){ return i.toFixed(0) }).join(delim) )
+write("")
+
 s = new Intonation({
   tet: 17,
 })
@@ -60,6 +108,13 @@ write("partch:")
 write( s.range(0, 44).map(function(i){ return i.toFixed(0) }).join(delim) )
 write("")
 
+s = new Intonation({
+  scl: document.querySelector("#meantone-scl").innerHTML
+})
+write("meantone.scl:")
+write( s.range(0, s.scale.length+1).map(function(i){ return i.toFixed(0) }).join(delim) )
+write("")
+
 </script>
 <script src="http://asdf.us/harp/js/vendor/Tone.min.js"></script>
 <script>
diff --git a/intonation.js b/intonation.js
index 509addd..8c12847 100644
--- a/intonation.js
+++ b/intonation.js
@@ -11,7 +11,10 @@ var Intonation = (function(){
   }
   Intonation.prototype.generate = function(opt){
     opt = Object.assign(this.opt, opt || {})
-    if (opt.tet) {
+    if (opt.scl) {
+      this.generate_scl()
+    }
+    else if (opt.tet) {
       this.generate_tet()
     }
     else if (opt.intervals) {
@@ -44,6 +47,52 @@ var Intonation = (function(){
     }
     this.intervals = null
   }
+  Intonation.prototype.generate_scl = function(){
+    var root = this.opt.root
+    var scl = this.parse_scl( this.opt.scl )
+    this.intervals = scl.notes
+    this.interval = scl.notes.pop()
+    this.scale = scl.notes.map(function(v){
+      return v * root
+    })
+  }
+  Intonation.prototype.parse_scl = function(s){
+    var scl = {}
+    scl.comments = []
+    scl.notes = []
+    s.trim().split("\n").forEach(function(line){
+      // Lines beginning with an exclamation mark are regarded as comments
+      // and are to be ignored.
+      if ( line.indexOf("!") !== -1 ) {
+        scl.comments.push(line)
+      }
+      // The first (non comment) line contains a short description of the scale.
+      // If there is no description, there should be an empty line. (nb: which is falsey)
+      else if ( ! ('description' in scl) ) {
+        scl.description = line
+      }
+      // The second line contains the number of notes.
+      // The first note of 1/1 or 0.0 cents is implicit and not in the files.
+      else if ( ! scl.notes.length) {
+        scl.notes.push(1)
+      }
+      else {
+        // If the value contains a period, it is a cents value, otherwise a ratio.
+        var note = line.replace(/^[^-\.0-9]+/,"").replace(/[^-\/\.0-9]+$/,"")
+        if ( note.indexOf(".") !== -1 ) {
+          note = Math.pow( 2, (parseFloat(note) / 1200) )
+        }
+        else {
+          console.log("note", line, note)
+          note = parseInterval(note)
+        }
+        if (note) {
+          scl.notes.push(note)
+        }
+      }
+    })
+    return scl
+  }
   Intonation.prototype.index = function(i, octave){
     octave = octave || this.opt.octave
     var f = this.scale[ mod(i, this.scale.length)|0 ]
-- 
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