text: /**
   * @license
   * Visual Blocks Language
   *
   * Copyright 2016 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 Generating Lua for logic blocks.
   * @author rodrigoq@google.com (Rodrigo Queiro)
   */
  'use strict';
  
  goog.provide('Blockly.Lua.logic');
  
  goog.require('Blockly.Lua');
  
  
  Blockly.Lua['controls_if'] = function(block) {
    // If/elseif/else condition.
    var n = 0;
    var code = '', branchCode, conditionCode;
    do {
      conditionCode = Blockly.Lua.valueToCode(block, 'IF' + n,
        Blockly.Lua.ORDER_NONE) || 'false';
      branchCode = Blockly.Lua.statementToCode(block, 'DO' + n);
      code += (n > 0 ? 'else' : '') +
          'if ' + conditionCode + ' then\n' + branchCode;
  
      ++n;
    } while (block.getInput('IF' + n));
  
    if (block.getInput('ELSE')) {
      branchCode = Blockly.Lua.statementToCode(block, 'ELSE');
      code += 'else\n' + branchCode;
    }
    return code + 'end\n';
  };
  
  Blockly.Lua['controls_ifelse'] = Blockly.Lua['controls_if'];
  
  Blockly.Lua['logic_compare'] = function(block) {
    // Comparison operator.
    var OPERATORS = {
      'EQ': '==',
      'NEQ': '~=',
      'LT': '<',
      'LTE': '<=',
      'GT': '>',
      'GTE': '>='
    };
    var operator = OPERATORS[block.getFieldValue('OP')];
    var argument0 = Blockly.Lua.valueToCode(block, 'A',
        Blockly.Lua.ORDER_RELATIONAL) || '0';
    var argument1 = Blockly.Lua.valueToCode(block, 'B',
        Blockly.Lua.ORDER_RELATIONAL) || '0';
    var code = argument0 + ' ' + operator + ' ' + argument1;
    return [code, Blockly.Lua.ORDER_RELATIONAL];
  };
  
  Blockly.Lua['logic_operation'] = function(block) {
    // Operations 'and', 'or'.
    var operator = (block.getFieldValue('OP') == 'AND') ? 'and' : 'or';
    var order = (operator == 'and') ? Blockly.Lua.ORDER_AND :
        Blockly.Lua.ORDER_OR;
    var argument0 = Blockly.Lua.valueToCode(block, 'A', order);
    var argument1 = Blockly.Lua.valueToCode(block, 'B', order);
    if (!argument0 && !argument1) {
      // If there are no arguments, then the return value is false.
      argument0 = 'false';
      argument1 = 'false';
    } else {
      // Single missing arguments have no effect on the return value.
      var defaultArgument = (operator == 'and') ? 'true' : 'false';
      if (!argument0) {
        argument0 = defaultArgument;
      }
      if (!argument1) {
        argument1 = defaultArgument;
      }
    }
    var code = argument0 + ' ' + operator + ' ' + argument1;
    return [code, order];
  };
  
  Blockly.Lua['logic_negate'] = function(block) {
    // Negation.
    var argument0 = Blockly.Lua.valueToCode(block, 'BOOL',
        Blockly.Lua.ORDER_UNARY) || 'true';
    var code = 'not ' + argument0;
    return [code, Blockly.Lua.ORDER_UNARY];
  };
  
  Blockly.Lua['logic_boolean'] = function(block) {
    // Boolean values true and false.
    var code = (block.getFieldValue('BOOL') == 'TRUE') ? 'true' : 'false';
    return [code, Blockly.Lua.ORDER_ATOMIC];
  };
  
  Blockly.Lua['logic_null'] = function(block) {
    // Null data type.
    return ['nil', Blockly.Lua.ORDER_ATOMIC];
  };
  
  Blockly.Lua['logic_ternary'] = function(block) {
    // Ternary operator.
    var value_if = Blockly.Lua.valueToCode(block, 'IF',
        Blockly.Lua.ORDER_AND) || 'false';
    var value_then = Blockly.Lua.valueToCode(block, 'THEN',
        Blockly.Lua.ORDER_AND) || 'nil';
    var value_else = Blockly.Lua.valueToCode(block, 'ELSE',
        Blockly.Lua.ORDER_OR) || 'nil';
    var code = value_if + ' and ' + value_then + ' or ' + value_else;
    return [code, Blockly.Lua.ORDER_OR];
  };
  