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+/**
+ * @license
+ * Visual Blocks Editor
+ *
+ * Copyright 2012 Google Inc.
+ * https://developers.google.com/blockly/
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Utility functions for generating executable code from
+ * Blockly code.
+ * @author fraser@google.com (Neil Fraser)
+ */
+'use strict';
+
+goog.provide('Blockly.Generator');
+
+goog.require('Blockly.Block');
+goog.require('goog.asserts');
+
+
+/**
+ * Class for a code generator that translates the blocks into a language.
+ * @param {string} name Language name of this generator.
+ * @constructor
+ */
+Blockly.Generator = function(name) {
+  this.name_ = name;
+  this.FUNCTION_NAME_PLACEHOLDER_REGEXP_ =
+      new RegExp(this.FUNCTION_NAME_PLACEHOLDER_, 'g');
+};
+
+/**
+ * Category to separate generated function names from variables and procedures.
+ */
+Blockly.Generator.NAME_TYPE = 'generated_function';
+
+/**
+ * Arbitrary code to inject into locations that risk causing infinite loops.
+ * Any instances of '%1' will be replaced by the block ID that failed.
+ * E.g. '  checkTimeout(%1);\n'
+ * @type {?string}
+ */
+Blockly.Generator.prototype.INFINITE_LOOP_TRAP = null;
+
+/**
+ * Arbitrary code to inject before every statement.
+ * Any instances of '%1' will be replaced by the block ID of the statement.
+ * E.g. 'highlight(%1);\n'
+ * @type {?string}
+ */
+Blockly.Generator.prototype.STATEMENT_PREFIX = null;
+
+/**
+ * The method of indenting.  Defaults to two spaces, but language generators
+ * may override this to increase indent or change to tabs.
+ * @type {string}
+ */
+Blockly.Generator.prototype.INDENT = '  ';
+
+/**
+ * Maximum length for a comment before wrapping.  Does not account for
+ * indenting level.
+ * @type {number}
+ */
+Blockly.Generator.prototype.COMMENT_WRAP = 60;
+
+/**
+ * List of outer-inner pairings that do NOT require parentheses.
+ * @type {!Array.<!Array.<number>>}
+ */
+Blockly.Generator.prototype.ORDER_OVERRIDES = [];
+
+/**
+ * Generate code for all blocks in the workspace to the specified language.
+ * @param {Blockly.Workspace} workspace Workspace to generate code from.
+ * @return {string} Generated code.
+ */
+Blockly.Generator.prototype.workspaceToCode = function(workspace) {
+  if (!workspace) {
+    // Backwards compatibility from before there could be multiple workspaces.
+    console.warn('No workspace specified in workspaceToCode call.  Guessing.');
+    workspace = Blockly.getMainWorkspace();
+  }
+  var code = [];
+  this.init(workspace);
+  var blocks = workspace.getTopBlocks(true);
+  for (var x = 0, block; block = blocks[x]; x++) {
+    var line = this.blockToCode(block);
+    if (goog.isArray(line)) {
+      // Value blocks return tuples of code and operator order.
+      // Top-level blocks don't care about operator order.
+      line = line[0];
+    }
+    if (line) {
+      if (block.outputConnection && this.scrubNakedValue) {
+        // This block is a naked value.  Ask the language's code generator if
+        // it wants to append a semicolon, or something.
+        line = this.scrubNakedValue(line);
+      }
+      code.push(line);
+    }
+  }
+  code = code.join('\n');  // Blank line between each section.
+  code = this.finish(code);
+  // Final scrubbing of whitespace.
+  code = code.replace(/^\s+\n/, '');
+  code = code.replace(/\n\s+$/, '\n');
+  code = code.replace(/[ \t]+\n/g, '\n');
+  return code;
+};
+
+// The following are some helpful functions which can be used by multiple
+// languages.
+
+/**
+ * Prepend a common prefix onto each line of code.
+ * @param {string} text The lines of code.
+ * @param {string} prefix The common prefix.
+ * @return {string} The prefixed lines of code.
+ */
+Blockly.Generator.prototype.prefixLines = function(text, prefix) {
+  return prefix + text.replace(/(?!\n$)\n/g, '\n' + prefix);
+};
+
+/**
+ * Recursively spider a tree of blocks, returning all their comments.
+ * @param {!Blockly.Block} block The block from which to start spidering.
+ * @return {string} Concatenated list of comments.
+ */
+Blockly.Generator.prototype.allNestedComments = function(block) {
+  var comments = [];
+  var blocks = block.getDescendants();
+  for (var i = 0; i < blocks.length; i++) {
+    var comment = blocks[i].getCommentText();
+    if (comment) {
+      comments.push(comment);
+    }
+  }
+  // Append an empty string to create a trailing line break when joined.
+  if (comments.length) {
+    comments.push('');
+  }
+  return comments.join('\n');
+};
+
+/**
+ * Generate code for the specified block (and attached blocks).
+ * @param {Blockly.Block} block The block to generate code for.
+ * @return {string|!Array} For statement blocks, the generated code.
+ *     For value blocks, an array containing the generated code and an
+ *     operator order value.  Returns '' if block is null.
+ */
+Blockly.Generator.prototype.blockToCode = function(block) {
+  if (!block) {
+    return '';
+  }
+  if (block.disabled) {
+    // Skip past this block if it is disabled.
+    return this.blockToCode(block.getNextBlock());
+  }
+
+  var func = this[block.type];
+  goog.asserts.assertFunction(func,
+      'Language "%s" does not know how to generate code for block type "%s".',
+      this.name_, block.type);
+  // First argument to func.call is the value of 'this' in the generator.
+  // Prior to 24 September 2013 'this' was the only way to access the block.
+  // The current prefered method of accessing the block is through the second
+  // argument to func.call, which becomes the first parameter to the generator.
+  var code = func.call(block, block);
+  if (goog.isArray(code)) {
+    // Value blocks return tuples of code and operator order.
+    goog.asserts.assert(block.outputConnection,
+        'Expecting string from statement block "%s".', block.type);
+    return [this.scrub_(block, code[0]), code[1]];
+  } else if (goog.isString(code)) {
+    if (this.STATEMENT_PREFIX) {
+      code = this.STATEMENT_PREFIX.replace(/%1/g, '\'' + block.id + '\'') +
+          code;
+    }
+    return this.scrub_(block, code);
+  } else if (code === null) {
+    // Block has handled code generation itself.
+    return '';
+  } else {
+    goog.asserts.fail('Invalid code generated: %s', code);
+  }
+};
+
+/**
+ * Generate code representing the specified value input.
+ * @param {!Blockly.Block} block The block containing the input.
+ * @param {string} name The name of the input.
+ * @param {number} outerOrder The maximum binding strength (minimum order value)
+ *     of any operators adjacent to "block".
+ * @return {string} Generated code or '' if no blocks are connected or the
+ *     specified input does not exist.
+ */
+Blockly.Generator.prototype.valueToCode = function(block, name, outerOrder) {
+  if (isNaN(outerOrder)) {
+    goog.asserts.fail('Expecting valid order from block "%s".', block.type);
+  }
+  var targetBlock = block.getInputTargetBlock(name);
+  if (!targetBlock) {
+    return '';
+  }
+  var tuple = this.blockToCode(targetBlock);
+  if (tuple === '') {
+    // Disabled block.
+    return '';
+  }
+  // Value blocks must return code and order of operations info.
+  // Statement blocks must only return code.
+  goog.asserts.assertArray(tuple, 'Expecting tuple from value block "%s".',
+      targetBlock.type);
+  var code = tuple[0];
+  var innerOrder = tuple[1];
+  if (isNaN(innerOrder)) {
+    goog.asserts.fail('Expecting valid order from value block "%s".',
+        targetBlock.type);
+  }
+  if (!code) {
+    return '';
+  }
+
+  // Add parentheses if needed.
+  var parensNeeded = false;
+  var outerOrderClass = Math.floor(outerOrder);
+  var innerOrderClass = Math.floor(innerOrder);
+  if (outerOrderClass <= innerOrderClass) {
+    if (outerOrderClass == innerOrderClass &&
+        (outerOrderClass == 0 || outerOrderClass == 99)) {
+      // Don't generate parens around NONE-NONE and ATOMIC-ATOMIC pairs.
+      // 0 is the atomic order, 99 is the none order.  No parentheses needed.
+      // In all known languages multiple such code blocks are not order
+      // sensitive.  In fact in Python ('a' 'b') 'c' would fail.
+    } else {
+      // The operators outside this code are stonger than the operators
+      // inside this code.  To prevent the code from being pulled apart,
+      // wrap the code in parentheses.
+      parensNeeded = true;
+      // Check for special exceptions.
+      for (var i = 0; i < this.ORDER_OVERRIDES.length; i++) {
+        if (this.ORDER_OVERRIDES[i][0] == outerOrder &&
+            this.ORDER_OVERRIDES[i][1] == innerOrder) {
+          parensNeeded = false;
+          break;
+        }
+      }
+    }
+  }
+  if (parensNeeded) {
+    // Technically, this should be handled on a language-by-language basis.
+    // However all known (sane) languages use parentheses for grouping.
+    code = '(' + code + ')';
+  }
+  return code;
+};
+
+/**
+ * Generate code representing the statement.  Indent the code.
+ * @param {!Blockly.Block} block The block containing the input.
+ * @param {string} name The name of the input.
+ * @return {string} Generated code or '' if no blocks are connected.
+ */
+Blockly.Generator.prototype.statementToCode = function(block, name) {
+  var targetBlock = block.getInputTargetBlock(name);
+  var code = this.blockToCode(targetBlock);
+  // Value blocks must return code and order of operations info.
+  // Statement blocks must only return code.
+  goog.asserts.assertString(code, 'Expecting code from statement block "%s".',
+      targetBlock && targetBlock.type);
+  if (code) {
+    code = this.prefixLines(/** @type {string} */ (code), this.INDENT);
+  }
+  return code;
+};
+
+/**
+ * Add an infinite loop trap to the contents of a loop.
+ * If loop is empty, add a statment prefix for the loop block.
+ * @param {string} branch Code for loop contents.
+ * @param {string} id ID of enclosing block.
+ * @return {string} Loop contents, with infinite loop trap added.
+ */
+Blockly.Generator.prototype.addLoopTrap = function(branch, id) {
+  if (this.INFINITE_LOOP_TRAP) {
+    branch = this.INFINITE_LOOP_TRAP.replace(/%1/g, '\'' + id + '\'') + branch;
+  }
+  if (this.STATEMENT_PREFIX) {
+    branch += this.prefixLines(this.STATEMENT_PREFIX.replace(/%1/g,
+        '\'' + id + '\''), this.INDENT);
+  }
+  return branch;
+};
+
+/**
+ * Comma-separated list of reserved words.
+ * @type {string}
+ * @private
+ */
+Blockly.Generator.prototype.RESERVED_WORDS_ = '';
+
+/**
+ * Add one or more words to the list of reserved words for this language.
+ * @param {string} words Comma-separated list of words to add to the list.
+ *     No spaces.  Duplicates are ok.
+ */
+Blockly.Generator.prototype.addReservedWords = function(words) {
+  this.RESERVED_WORDS_ += words + ',';
+};
+
+/**
+ * This is used as a placeholder in functions defined using
+ * Blockly.Generator.provideFunction_.  It must not be legal code that could
+ * legitimately appear in a function definition (or comment), and it must
+ * not confuse the regular expression parser.
+ * @type {string}
+ * @private
+ */
+Blockly.Generator.prototype.FUNCTION_NAME_PLACEHOLDER_ = '{leCUI8hutHZI4480Dc}';
+
+/**
+ * Define a function to be included in the generated code.
+ * The first time this is called with a given desiredName, the code is
+ * saved and an actual name is generated.  Subsequent calls with the
+ * same desiredName have no effect but have the same return value.
+ *
+ * It is up to the caller to make sure the same desiredName is not
+ * used for different code values.
+ *
+ * The code gets output when Blockly.Generator.finish() is called.
+ *
+ * @param {string} desiredName The desired name of the function (e.g., isPrime).
+ * @param {!Array.<string>} code A list of statements.  Use '  ' for indents.
+ * @return {string} The actual name of the new function.  This may differ
+ *     from desiredName if the former has already been taken by the user.
+ * @private
+ */
+Blockly.Generator.prototype.provideFunction_ = function(desiredName, code) {
+  if (!this.definitions_[desiredName]) {
+    var functionName = this.variableDB_.getDistinctName(desiredName,
+        Blockly.Procedures.NAME_TYPE);
+    this.functionNames_[desiredName] = functionName;
+    var codeText = code.join('\n').replace(
+        this.FUNCTION_NAME_PLACEHOLDER_REGEXP_, functionName);
+    // Change all '  ' indents into the desired indent.
+    var oldCodeText;
+    while (oldCodeText != codeText) {
+      oldCodeText = codeText;
+      codeText = codeText.replace(/^((  )*)  /gm, '$1' + this.INDENT);
+    }
+    this.definitions_[desiredName] = codeText;
+  }
+  return this.functionNames_[desiredName];
+};