Added Arduino Stepper library code blocks and generators:

One block required to configure a stepper class instance, and another block used to set the number of steps to move.
The setter block dynamically picks any existing instance of a stepper class and generates a drop down menu (similar to the variables blocks).
Still to do is to add an lister and handler to update the menu when the instance names changes.

apps/arduino/template.soy

@@ -38,6 +38,7 @@
   <script type="text/javascript" src="../../generators/arduino/math.js"></script>
   <script type="text/javascript" src="../../generators/arduino/procedures.js"></script>
   <script type="text/javascript" src="../../generators/arduino/servo.js"></script>
+  <script type="text/javascript" src="../../generators/arduino/stepper.js"></script>
   <script type="text/javascript" src="../../generators/arduino/text.js"></script>
   <script type="text/javascript" src="../../generators/arduino/time.js"></script>
   <script type="text/javascript" src="../../generators/arduino/variables.js"></script>
@@ -288,6 +289,10 @@
       <block type="servo_write"></block>
       <block type="servo_read"></block>
     </category>
+    <category name="{msg meaning="Apps.catStepper" desc="IBID"}Stepper{/msg}">
+      <block type="stepper_configure"></block>
+      <block type="stepper_step"></block>
+    </category>
   </xml>
 {/template}
 
@@ -308,6 +313,7 @@
   <script type="text/javascript" src="../../generators/arduino/math.js"></script>
   <script type="text/javascript" src="../../generators/arduino/procedures.js"></script>
   <script type="text/javascript" src="../../generators/arduino/servo.js"></script>
+  <script type="text/javascript" src="../../generators/arduino/stepper.js"></script>
   <script type="text/javascript" src="../../generators/arduino/text.js"></script>
   <script type="text/javascript" src="../../generators/arduino/time.js"></script>
   <script type="text/javascript" src="../../generators/arduino/variables.js"></script>

generators/arduino.js

@@ -76,7 +76,7 @@ var profile = {
     interrupt: [["Int_1", "1"], ["Int_2", "2"], ["Int_3", "3"], ["Int_4", "4"], ["Int_5", "5"]],
     serial : [["300", "300"], ["600", "600"], ["1200", "1200"], ["2400", "2400"], ["4800", "4800"], ["9600", "9600"], ["14400", "14400"], ["19200", "19200"], ["28800", "28800"], ["31250", "31250"], ["38400", "38400"],["57600", "57600"], ["115200", "115200"]],
     builtin_led: [["BUILTIN_1", "13"]],
-    pin_types: { INPUT: "INPUT", OUTPUT: "OUTPUT", PWM: "PWM", SERVO: "SERVO" },
+    pin_types: { INPUT: "INPUT", OUTPUT: "OUTPUT", PWM: "PWM", SERVO: "SERVO" , STEPPER: "STEPPER" },
     types : [["void", "void"], ["Boolean", "boolean"], ["Character", "char"], ["Unsigned Character", "unsigned char"], ["Byte", "byte"], ["Integer", "int"], ["Unsigned Integer", "unsigned int"], ["Word", "word"], ["Long", "long"], ["Unsigned Long", "unsigned long"], ["Short", "short"], ["Float", "float"], ["Double", "double"], ["String", "String"], ["Char Array", "string"], ["Array", "array"]]
   },
   arduino_mega:{

generators/arduino/stepper.js

+/**
+ * @fileoverview Blocks extension for Arduino Stepper library.
+ * The Arduino Servo functions syntax can be found in the following URL
+ * http://arduino.cc/en/Reference/Stepper
+ * Additional functions apart from the normal generators have been added to be
+ * able to generate the 'set' drop down menu with all current instaces of the
+ * Stepper class:
+ * Blockly.Arduino.stepper.allInstances
+ * Blockly.Arduino.stepper.FieldSetterInstance
+ * Blockly.Arduino.stepper.FieldSetterInstance.dropdownCreate
+ * 
+ * TODO: Still need to had some kind of handler to refresh the "set" drop down
+ *       menu values if an instance in a 'configure' block is renamed.
+ */
+'use strict';
+
+goog.provide('Blockly.Arduino.stepper');
+
+goog.require('Blockly.Arduino');
+
+goog.require('Blockly.FieldDropdown');
+
+
+/**
+ * Finds all user-created instances of the Stepper block config.
+ * Based on Blockly.Variables.allVariables
+ * @return {!Array.<string>} Array of instance names.
+ */
+Blockly.Arduino.stepper.allInstances = function() {
+  var blocks = Blockly.mainWorkspace.getAllBlocks();
+  var variableHash = Object.create(null);
+
+  // Iterate through every block and add each Stetter config name to the hash.
+  for (var x = 0; x < blocks.length; x++) {
+    var func = blocks[x].getInstance;
+    if (func) {
+      var blockVariables = func.call(blocks[x]);
+      for (var y = 0; y < blockVariables.length; y++) {
+        var varName = blockVariables[y];
+        // Variable name may be null if the block is only half-built.
+        if (varName) {
+          variableHash[varName.toLowerCase()] = varName;
+        }
+      }
+    }
+  }
+  // Flatten the hash into a list.
+  var variableList = [];
+  for (var name in variableHash) {
+    variableList.push(variableHash[name]);
+  }
+
+  return variableList;
+};
+
+/**
+ * Class for a variable's dropdown field.
+ * @param {Function} opt_changeHandler A function that is executed when a new
+ *     option is selected.  Its sole argument is the new option value.  Its
+ *     return value is ignored.
+ * @extends {Blockly.FieldDropdown}
+ * @constructor
+ */
+Blockly.Arduino.stepper.FieldSetterInstance = function() {
+  Blockly.Arduino.stepper.FieldSetterInstance.superClass_.constructor.call(this,
+      Blockly.Arduino.stepper.FieldSetterInstance.dropdownCreate);
+};
+goog.inherits(Blockly.Arduino.stepper.FieldSetterInstance, Blockly.FieldDropdown);
+
+/**
+ * Return a sorted list of instances names for set dropdown menu.
+ * @return {!Array.<string>} Array of variable names.
+ * @this {!Blockly.FieldSetterInstance}
+ */
+Blockly.Arduino.stepper.FieldSetterInstance.dropdownCreate = function() {
+  var variableList = Blockly.Arduino.stepper.allInstances();
+  variableList.sort(goog.string.caseInsensitiveCompare);
+  // Variables are not language-specific, use the name as both the user-facing
+  // text and the internal representation.
+  var options = [];
+  for (var x = 0; x < variableList.length; x++) {
+    options[x] = [variableList[x], variableList[x]];
+  }
+  return options;
+};
+
+/**
+ * Block for for the stepper generator configuration including creating
+ * an object instance and setting up the speed. Info in the setHelpUrl link.
+ * @this Blockly.Block
+ */
+Blockly.Blocks['stepper_configure'] = {
+  /**
+   * Block for Stepper configuration.
+   * @this Blockly.Block
+   */
+  init: function() {
+    this.setHelpUrl('http://arduino.cc/en/Reference/StepperConstructor');
+    this.setColour(75);
+    this.appendDummyInput()
+        .appendField('Configure STEPPER:');
+    this.appendDummyInput()
+        .appendField('PIN1#')
+        .appendField(new Blockly.FieldDropdown(profile.default.digital),
+            'STEPPER_PIN1')
+        .appendField('PIN2#')
+        .appendField(new Blockly.FieldDropdown(profile.default.digital),
+            'STEPPER_PIN2');
+    this.appendValueInput('STEPPER_STEPS')
+        .setCheck('Number')
+        .appendField('Steps in one revolution');
+    this.appendValueInput('STEPPER_SPEED')
+        .setCheck('Number')
+        .appendField('Set speed to');
+    this.appendValueInput('STEPPER_NAME')
+        .setCheck('String')
+        .appendField('Set name to');
+    this.setTooltip('');
+    //this.contextMenuMsg_ = Blockly.Msg.VARIABLES_GET_CREATE_SET;
+    //this.contextMenuType_ = 'stepper_step';
+  },
+  /**
+   * Returns the stepper instance name, defined in the 'STEPPER_NAME' input
+   * String block attached to this block.
+   * @return {!Array.<string>} List with the instaces name.
+   * @this Blockly.Block
+   */
+  getInstance: function() {
+    var InstanceNamefromBlock;
+    var targetBlock = this.getInputTargetBlock('STEPPER_NAME');
+    if (!targetBlock) {
+      InstanceNamefromBlock = 'Empty_input_name';
+      this.setWarningText('A STEPPER configuration block needs to have a ' +
+        'name to set the motor steps!');
+    } else {
+      InstanceNamefromBlock = targetBlock.getFieldValue('TEXT');
+      this.setWarningText(null);
+    }
+    return [InstanceNamefromBlock];
+  }
+};
+
+/**
+ * Code generator for the stepper generator configuration. Nothing is added 
+ * to the 'loop()' function, just the library define, global instance and 
+ * a function call in 'setup()'.
+ * @param {block} block Block to generate the code from.
+ * @return {string} Empty string as no code goes into 'loop()' 
+ */
+Blockly.Arduino['stepper_configure'] = function(block) {
+  var pin1 = block.getFieldValue('STEPPER_PIN1');
+  var pin2 = block.getFieldValue('STEPPER_PIN2');
+  var pin_type = profile.default.pin_types.STEPPER;
+  var stepper_name = block.getInstance();
+  var stepper_steps = Blockly.Arduino.valueToCode(block, 'STEPPER_STEPS',
+      Blockly.Arduino.ORDER_ATOMIC) || '360';
+  var stepper_speed = Blockly.Arduino.valueToCode(block, 'STEPPER_SPEED',
+      Blockly.Arduino.ORDER_ATOMIC) || '90';
+  var global_code = 'Stepper ' + stepper_name + '(' + stepper_steps + ', ' +
+      pin1 + ', ' + pin2 + ');';
+  var setup_code = stepper_name + '.setSpeed(' + stepper_speed + ');';
+
+  // Maintain the setup regardless of pin conflict, warning should be enough
+  Blockly.Arduino.definitions_['define_stepper'] = '#include <Stepper.h>\n';
+  Blockly.Arduino.definitions_['global_stepper_' + stepper_name] = global_code;
+  Blockly.Arduino.setups_['setup_stepper_' + stepper_name] = setup_code;
+
+  // If the IO has been configured already set a block warning for the user
+  var warning_text = '';
+  if (pin1 in Blockly.Arduino.pins_) {
+    if (Blockly.Arduino.pins_[pin1] != pin_type) {
+      warning_text = 'Pin ' + pin1 + ' alredy used as ' +
+          Blockly.Arduino.pins_[pin1] + '. ';
+    }
+  }
+  if (pin2 in Blockly.Arduino.pins_) {
+    if (Blockly.Arduino.pins_[pin2] != pin_type) {
+      warning_text = warning_text + 'Pin ' + pin2 + ' alredy used as ' +
+          Blockly.Arduino.pins_[pin2] + '. ';
+    }
+  }
+  if (warning_text === '') {
+    // First time this IO pin is used, so configure it
+    Blockly.Arduino.pins_[pin1] = pin_type;
+    Blockly.Arduino.pins_[pin2] = pin_type;
+    block.setWarningText(null);
+  } else {
+    block.setWarningText(warning_text);
+  }
+
+  return '';
+};
+
+/**
+ * Block for for the stepper 'step()' function.
+ * @this Blockly.Block
+ */
+Blockly.Blocks['stepper_step'] = {
+  init: function() {
+    this.setHelpUrl('http://arduino.cc/en/Reference/StepperStep');
+    this.setColour(75);
+    this.interpolateMsg(
+        // TODO: Combine these messages instead of using concatenation.
+        'STEPPER' + ' %1 ' +
+        'move' + ' %2' + 'steps',
+        ['STEPPER_NAME', new Blockly.Arduino.stepper.FieldSetterInstance()],
+        ['STEPPER_STEPS', 'Number', Blockly.ALIGN_RIGHT],
+        Blockly.ALIGN_RIGHT);
+    this.setPreviousStatement(true);
+    this.setNextStatement(true);
+    this.setTooltip('Turns the stepper motor a specific number of steps.');
+  }
+};
+
+/**
+ * Code generator for the stepper 'step()' function. Info in the setHelpUrl link.
+ * @param {block} block Block to generate the code from.
+ * @return {array} Completed code with order of operation.
+ */
+Blockly.Arduino['stepper_step'] = function(block) {
+  var stepper_instance = block.getFieldValue('STEPPER_NAME');
+  var stepper_steps = Blockly.Arduino.valueToCode(block, 'STEPPER_STEPS',
+      Blockly.Arduino.ORDER_ATOMIC) || '0';
+  var code = '';
+  
+  // Only write the code if an instance has been configured
+  if (stepper_instance != 'Empty_input_name') {
+    code = stepper_instance + '.steps(' + stepper_steps + ')';
+    block.setWarningText(null);
+  } else {
+    block.setWarningText('A STEPPER configuration block has to be added in ' +
+        'to be able to use this block!');
+  }
+  
+  return [code, Blockly.Arduino.ORDER_ATOMIC];
+};