Simplification: removed Gen and Tr, retaining Env.

lib/music.rb

@@ -21,7 +21,7 @@
 require 'music/key'
 require 'music/interpreter'
 require 'music/score'
-require 'music/gens'
+require 'music/env'
 require 'music/timeline'
 require 'music/smf_writer'
 

lib/music/env.rb

@@ -0,0 +1,11 @@
+module Music
+  class Env
+    def initialize(&fn)
+      @fn = fn
+    end
+
+    def apply(name, val, context)
+      @fn.call(val, context.phase)
+    end
+  end
+end

lib/music/interpreter.rb

@@ -48,7 +48,7 @@ def accept(a0)
         push(names.inject({}) { |a1, name|
           a1.merge name => case new = self.attributes[name]
             # If a0 yields a Gen, apply it
-            when Gen: new.apply(name, a0[name], self)
+            when Env: new.apply(name, a0[name], self)
             # otherwise, inherit the attribute value from a0 if
             # we haven't defined it
             else self.attributes[name] || a0[name]

spec/gens_spec.rb → spec/env_spec.rb

@@ -1,29 +1,5 @@
 require File.join( File.dirname(__FILE__), 'spec_helper')
 
-describe Gen do
-  before(:all) do
-    @score = s( n(c4, 1),
-                :amp => gen { |c| 0.5 })
-  end
-
-  it "should generate values from the given context" do
-    timeline = @score.to_timeline
-    timeline[0].amp.should == 0.5
-  end
-end
-
-describe Tr do
-  before(:all) do
-    @score = s( n(c4, 1, :amp => 0.5),
-                :amp => tr { |amp| amp * 0.5 } )
-  end
-
-  it "should transform attribute values" do
-    timeline = @score.to_timeline
-    timeline[0].amp.should == 0.25
-  end
-end
-
 describe Env do
   it "should transform attribute values based on their phase" do
     score = s( seq(n([c4, e4, g4], 1, :amp => 0.5)),