parsing scl files

1 files changed, 50 insertions, 1 deletions

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 ]