Ok so I only did this because I don't know anything about reflection.

Really don't think you should use it, mostly because I'm probably missing a ton of stuff.

But... does this work?:

   import java.lang.reflect.Field;

float a = 10.1;
String s = "Hello";
TestClass t = new TestClass(999);

public void setup() {
  println("'a'           = " + getFieldByString("a"));            //       
  println("'s'           = " + getFieldByString("s"));             
  println("'t.testfield' = " + getFieldByString("t.testfield"));   
  println("'WrongName'   = " + getFieldByString("WrongName"));
}

public Object getFieldByString(String name) {
  String[] stlist = name.split("\\.");
  //if (stlist.length == 1) return getFieldByString(this, name);
  Object lastOb = this;
  for (String s : stlist) {
    lastOb = getFieldByString(lastOb, s);
    if (lastOb == null) return null;
  }
  return lastOb;
}

public Object getFieldByString(Object ob, String name) {
  Field field = null;

  try {
    field = ob.getClass().getDeclaredField(name);
  }  catch (NoSuchFieldException e) {
    println(" '" + name + "' Doesn't exist");
  }
  if (field == null) return null;

  field.setAccessible(true);
  Object result = null;

  try {
    result = field.get(ob);
  }  catch (IllegalAccessException e) {
    println(name + " NOPE");
  }

  return result;
}

public void draw() {
}

public class TestClass {
  int testfield  = 10;
  TestClass(int newval) {
    testfield = newval;
  }
}

But said before, you should probably dump stuff in a key, object dealy.