srecord Channels<A>(A[] data) {
  *(int n) { data = newGenericArray(n); }
  
  int channels() { ret l(data); }
  
  A get(int channel) { ret data[channel]; }
  
  void set(int channel, A a) { data[channel] = a; }
  
  A first() { ret main first(data); }
  A getSingleton() { assertEquals(1, channels()); ret first(); }
  
  toString { ret "Channels[" + joinWithComma(data) + "]"; }
}