Switch Newton over to using imports rather than parts

Fixes #1355

packages/newton/lib/newton.dart

@@ -5,16 +5,12 @@
 /// Simple Physics Simulations for Dart. Springs, friction, gravity, etc.
 library newton;
 
-import 'dart:math' as math;
+export 'src/clamped_simulation.dart';
-
+export 'src/friction_simulation.dart';
-part 'src/simulation.dart';
+export 'src/gravity_simulation.dart';
-part 'src/simulation_group.dart';
+export 'src/scroll_simulation.dart';
-part 'src/tolerance.dart';
+export 'src/simulation_group.dart';
-part 'src/utils.dart';
+export 'src/simulation.dart';
-
+export 'src/spring_simulation.dart';
-part 'src/clamped_simulation.dart';
+export 'src/tolerance.dart';
-part 'src/friction_simulation.dart';
+export 'src/utils.dart';
-part 'src/gravity_simulation.dart';
-part 'src/scroll_simulation.dart';
-part 'src/spring_simulation.dart';
-part 'src/spring_solution.dart';

packages/newton/lib/src/clamped_simulation.dart

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-part of newton;
+import 'simulation.dart';
 
 class ClampedSimulation extends Simulation {
   ClampedSimulation(this.simulation, {

packages/newton/lib/src/friction_simulation.dart

@@ -1,8 +1,11 @@
-// Copyright (c) 2015 The Chromium Authors. All rights reserved.
+// Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-part of newton;
+import 'dart:math' as math;
+
+import 'simulation.dart';
+import 'tolerance.dart';
 
 class FrictionSimulation extends Simulation {
   final double _drag;

packages/newton/lib/src/gravity_simulation.dart

@@ -1,8 +1,8 @@
-// Copyright (c) 2015 The Chromium Authors. All rights reserved.
+// Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-part of newton;
+import 'simulation.dart';
 
 class GravitySimulation extends Simulation {
   final double _x;

packages/newton/lib/src/scroll_simulation.dart

@@ -1,8 +1,11 @@
-// Copyright (c) 2015 The Chromium Authors. All rights reserved.
+// Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-part of newton;
+import 'friction_simulation.dart';
+import 'simulation_group.dart';
+import 'simulation.dart';
+import 'spring_simulation.dart';
 
 /// Simulates kinetic scrolling behavior between a leading and trailing
 /// boundary. Friction is applied within the extends and a spring action applied

packages/newton/lib/src/simulation.dart

@@ -1,8 +1,8 @@
-// Copyright (c) 2015 The Chromium Authors. All rights reserved.
+// Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-part of newton;
+import 'tolerance.dart';
 
 abstract class Simulatable {
   /// The current position of the object in the simulation

packages/newton/lib/src/simulation_group.dart

@@ -1,8 +1,10 @@
-// Copyright (c) 2015 The Chromium Authors. All rights reserved.
+// Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-part of newton;
+import 'simulation.dart';
+import 'tolerance.dart';
+import 'utils.dart';
 
 /// The abstract base class for all composite simulations. Concrete subclasses
 /// must implement the appropriate methods to select the appropriate simulation
@@ -46,7 +48,7 @@ abstract class SimulationGroup extends Simulation {
 
   double _lastStep = -1.0;
   void _stepIfNecessary(double time) {
-    if (_nearEqual(_lastStep, time, toleranceDefault.time)) {
+    if (nearEqual(_lastStep, time, toleranceDefault.time)) {
       return;
     }
 

packages/newton/lib/src/spring_simulation.dart

@@ -1,8 +1,124 @@
-// Copyright (c) 2015 The Chromium Authors. All rights reserved.
+// Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-part of newton;
+import 'dart:math' as math;
+
+import 'simulation.dart';
+import 'utils.dart';
+
+abstract class _SpringSolution implements Simulatable {
+  factory _SpringSolution(
+      SpringDescription desc, double initialPosition, double initialVelocity) {
+    double cmk =
+        desc.damping * desc.damping - 4 * desc.mass * desc.springConstant;
+
+    if (cmk == 0.0) {
+      return new _CriticalSolution(desc, initialPosition, initialVelocity);
+    } else if (cmk > 0.0) {
+      return new _OverdampedSolution(desc, initialPosition, initialVelocity);
+    } else {
+      return new _UnderdampedSolution(desc, initialPosition, initialVelocity);
+    }
+
+    return null;
+  }
+
+  SpringType get type;
+}
+
+class _CriticalSolution implements _SpringSolution {
+  final double _r, _c1, _c2;
+
+  factory _CriticalSolution(
+      SpringDescription desc, double distance, double velocity) {
+    final double r = -desc.damping / (2.0 * desc.mass);
+    final double c1 = distance;
+    final double c2 = velocity / (r * distance);
+    return new _CriticalSolution.withArgs(r, c1, c2);
+  }
+
+  SpringType get type => SpringType.criticallyDamped;
+
+  _CriticalSolution.withArgs(double r, double c1, double c2)
+      : _r = r,
+        _c1 = c1,
+        _c2 = c2;
+
+  double x(double time) => (_c1 + _c2 * time) * math.pow(math.E, _r * time);
+
+  double dx(double time) {
+    final double power = math.pow(math.E, _r * time);
+    return _r * (_c1 + _c2 * time) * power + _c2 * power;
+  }
+}
+
+class _OverdampedSolution implements _SpringSolution {
+  final double _r1, _r2, _c1, _c2;
+
+  factory _OverdampedSolution(
+      SpringDescription desc, double distance, double velocity) {
+    final double cmk =
+        desc.damping * desc.damping - 4 * desc.mass * desc.springConstant;
+
+    final double r1 = (-desc.damping - math.sqrt(cmk)) / (2.0 * desc.mass);
+    final double r2 = (-desc.damping + math.sqrt(cmk)) / (2.0 * desc.mass);
+    final double c2 = (velocity - r1 * distance) / (r2 - r1);
+    final double c1 = distance - c2;
+
+    return new _OverdampedSolution.withArgs(r1, r2, c1, c2);
+  }
+
+  _OverdampedSolution.withArgs(double r1, double r2, double c1, double c2)
+      : _r1 = r1,
+        _r2 = r2,
+        _c1 = c1,
+        _c2 = c2;
+
+  SpringType get type => SpringType.overDamped;
+
+  double x(double time) =>
+      (_c1 * math.pow(math.E, _r1 * time) + _c2 * math.pow(math.E, _r2 * time));
+
+  double dx(double time) => (_c1 * _r1 * math.pow(math.E, _r1 * time) +
+      _c2 * _r2 * math.pow(math.E, _r2 * time));
+}
+
+class _UnderdampedSolution implements _SpringSolution {
+  final double _w, _r, _c1, _c2;
+
+  factory _UnderdampedSolution(
+      SpringDescription desc, double distance, double velocity) {
+    final double w = math.sqrt(4.0 * desc.mass * desc.springConstant -
+            desc.damping * desc.damping) /
+        (2.0 * desc.mass);
+    final double r = -(desc.damping / 2.0 * desc.mass);
+    final double c1 = distance;
+    final double c2 = (velocity - r * distance) / w;
+
+    return new _UnderdampedSolution.withArgs(w, r, c1, c2);
+  }
+
+  _UnderdampedSolution.withArgs(double w, double r, double c1, double c2)
+      : _w = w,
+        _r = r,
+        _c1 = c1,
+        _c2 = c2;
+
+  SpringType get type => SpringType.underDamped;
+
+  double x(double time) => math.pow(math.E, _r * time) *
+      (_c1 * math.cos(_w * time) + _c2 * math.sin(_w * time));
+
+  double dx(double time) {
+    final double power = math.pow(math.E, _r * time);
+    final double cosine = math.cos(_w * time);
+    final double sine = math.sin(_w * time);
+
+    return power * (_c2 * _w * cosine - _c1 * _w * sine) +
+        _r * power * (_c2 * sine + _c1 * cosine);
+  }
+}
 
 class SpringDescription {
   /// The mass of the spring (m)
@@ -58,8 +174,8 @@ class SpringSimulation extends Simulation {
   double dx(double time) => _solution.dx(time);
 
   bool isDone(double time) {
-    return _nearZero(_solution.x(time), tolerance.distance) &&
+    return nearZero(_solution.x(time), tolerance.distance) &&
-           _nearZero(_solution.dx(time), tolerance.velocity);
+           nearZero(_solution.dx(time), tolerance.velocity);
   }
 }
 

packages/newton/lib/src/spring_solution.dart

@@ -1,118 +0,0 @@
-// Copyright (c) 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-part of newton;
-
-abstract class _SpringSolution implements Simulatable {
-  factory _SpringSolution(
-      SpringDescription desc, double initialPosition, double initialVelocity) {
-    double cmk =
-        desc.damping * desc.damping - 4 * desc.mass * desc.springConstant;
-
-    if (cmk == 0.0) {
-      return new _CriticalSolution(desc, initialPosition, initialVelocity);
-    } else if (cmk > 0.0) {
-      return new _OverdampedSolution(desc, initialPosition, initialVelocity);
-    } else {
-      return new _UnderdampedSolution(desc, initialPosition, initialVelocity);
-    }
-
-    return null;
-  }
-
-  SpringType get type;
-}
-
-class _CriticalSolution implements _SpringSolution {
-  final double _r, _c1, _c2;
-
-  factory _CriticalSolution(
-      SpringDescription desc, double distance, double velocity) {
-    final double r = -desc.damping / (2.0 * desc.mass);
-    final double c1 = distance;
-    final double c2 = velocity / (r * distance);
-    return new _CriticalSolution.withArgs(r, c1, c2);
-  }
-
-  SpringType get type => SpringType.criticallyDamped;
-
-  _CriticalSolution.withArgs(double r, double c1, double c2)
-      : _r = r,
-        _c1 = c1,
-        _c2 = c2;
-
-  double x(double time) => (_c1 + _c2 * time) * math.pow(math.E, _r * time);
-
-  double dx(double time) {
-    final double power = math.pow(math.E, _r * time);
-    return _r * (_c1 + _c2 * time) * power + _c2 * power;
-  }
-}
-
-class _OverdampedSolution implements _SpringSolution {
-  final double _r1, _r2, _c1, _c2;
-
-  factory _OverdampedSolution(
-      SpringDescription desc, double distance, double velocity) {
-    final double cmk =
-        desc.damping * desc.damping - 4 * desc.mass * desc.springConstant;
-
-    final double r1 = (-desc.damping - math.sqrt(cmk)) / (2.0 * desc.mass);
-    final double r2 = (-desc.damping + math.sqrt(cmk)) / (2.0 * desc.mass);
-    final double c2 = (velocity - r1 * distance) / (r2 - r1);
-    final double c1 = distance - c2;
-
-    return new _OverdampedSolution.withArgs(r1, r2, c1, c2);
-  }
-
-  _OverdampedSolution.withArgs(double r1, double r2, double c1, double c2)
-      : _r1 = r1,
-        _r2 = r2,
-        _c1 = c1,
-        _c2 = c2;
-
-  SpringType get type => SpringType.overDamped;
-
-  double x(double time) =>
-      (_c1 * math.pow(math.E, _r1 * time) + _c2 * math.pow(math.E, _r2 * time));
-
-  double dx(double time) => (_c1 * _r1 * math.pow(math.E, _r1 * time) +
-      _c2 * _r2 * math.pow(math.E, _r2 * time));
-}
-
-class _UnderdampedSolution implements _SpringSolution {
-  final double _w, _r, _c1, _c2;
-
-  factory _UnderdampedSolution(
-      SpringDescription desc, double distance, double velocity) {
-    final double w = math.sqrt(4.0 * desc.mass * desc.springConstant -
-            desc.damping * desc.damping) /
-        (2.0 * desc.mass);
-    final double r = -(desc.damping / 2.0 * desc.mass);
-    final double c1 = distance;
-    final double c2 = (velocity - r * distance) / w;
-
-    return new _UnderdampedSolution.withArgs(w, r, c1, c2);
-  }
-
-  _UnderdampedSolution.withArgs(double w, double r, double c1, double c2)
-      : _w = w,
-        _r = r,
-        _c1 = c1,
-        _c2 = c2;
-
-  SpringType get type => SpringType.underDamped;
-
-  double x(double time) => math.pow(math.E, _r * time) *
-      (_c1 * math.cos(_w * time) + _c2 * math.sin(_w * time));
-
-  double dx(double time) {
-    final double power = math.pow(math.E, _r * time);
-    final double cosine = math.cos(_w * time);
-    final double sine = math.sin(_w * time);
-
-    return power * (_c2 * _w * cosine - _c1 * _w * sine) +
-        _r * power * (_c2 * sine + _c1 * cosine);
-  }
-}

packages/newton/lib/src/tolerance.dart

@@ -1,9 +1,7 @@
-// Copyright (c) 2015 The Chromium Authors. All rights reserved.
+// Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-part of newton;
-
 class Tolerance {
   final double distance;
   final double time;

packages/newton/lib/src/utils.dart

@@ -1,10 +1,8 @@
-// Copyright (c) 2015 The Chromium Authors. All rights reserved.
+// Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-part of newton;
+bool nearEqual(double a, double b, double epsilon) =>
-
-bool _nearEqual(double a, double b, double epsilon) =>
     (a > (b - epsilon)) && (a < (b + epsilon));
 
-bool _nearZero(double a, double epsilon) => _nearEqual(a, 0.0, epsilon);
+bool nearZero(double a, double epsilon) => nearEqual(a, 0.0, epsilon);