text: /**
   * @license
   * Copyright 2014 Google LLC
   * SPDX-License-Identifier: Apache-2.0
   */
  
  /**
   * @fileoverview Generating Dart for loop blocks.
   */
  'use strict';
  
  goog.module('Blockly.Dart.loops');
  
  const Dart = goog.require('Blockly.Dart');
  const stringUtils = goog.require('Blockly.utils.string');
  const {NameType} = goog.require('Blockly.Names');
  
  
  Dart['controls_repeat_ext'] = function(block) {
    let repeats;
    // Repeat n times.
    if (block.getField('TIMES')) {
      // Internal number.
      repeats = String(Number(block.getFieldValue('TIMES')));
    } else {
      // External number.
      repeats = Dart.valueToCode(block, 'TIMES', Dart.ORDER_ASSIGNMENT) || '0';
    }
    let branch = Dart.statementToCode(block, 'DO');
    branch = Dart.addLoopTrap(branch, block);
    let code = '';
    const loopVar = Dart.nameDB_.getDistinctName('count', NameType.VARIABLE);
    let endVar = repeats;
    if (!repeats.match(/^\w+$/) && !stringUtils.isNumber(repeats)) {
      endVar = Dart.nameDB_.getDistinctName('repeat_end', NameType.VARIABLE);
      code += 'var ' + endVar + ' = ' + repeats + ';\n';
    }
    code += 'for (int ' + loopVar + ' = 0; ' + loopVar + ' < ' + endVar + '; ' +
        loopVar + '++) {\n' + branch + '}\n';
    return code;
  };
  
  Dart['controls_repeat'] = Dart['controls_repeat_ext'];
  
  Dart['controls_whileUntil'] = function(block) {
    // Do while/until loop.
    const until = block.getFieldValue('MODE') === 'UNTIL';
    let argument0 =
        Dart.valueToCode(
            block, 'BOOL', until ? Dart.ORDER_UNARY_PREFIX : Dart.ORDER_NONE) ||
        'false';
    let branch = Dart.statementToCode(block, 'DO');
    branch = Dart.addLoopTrap(branch, block);
    if (until) {
      argument0 = '!' + argument0;
    }
    return 'while (' + argument0 + ') {\n' + branch + '}\n';
  };
  
  Dart['controls_for'] = function(block) {
    // For loop.
    const variable0 =
        Dart.nameDB_.getName(block.getFieldValue('VAR'), NameType.VARIABLE);
    const argument0 =
        Dart.valueToCode(block, 'FROM', Dart.ORDER_ASSIGNMENT) || '0';
    const argument1 = Dart.valueToCode(block, 'TO', Dart.ORDER_ASSIGNMENT) || '0';
    const increment = Dart.valueToCode(block, 'BY', Dart.ORDER_ASSIGNMENT) || '1';
    let branch = Dart.statementToCode(block, 'DO');
    branch = Dart.addLoopTrap(branch, block);
    let code;
    if (stringUtils.isNumber(argument0) && stringUtils.isNumber(argument1) &&
        stringUtils.isNumber(increment)) {
      // All arguments are simple numbers.
      const up = Number(argument0) <= Number(argument1);
      code = 'for (' + variable0 + ' = ' + argument0 + '; ' + variable0 +
          (up ? ' <= ' : ' >= ') + argument1 + '; ' + variable0;
      const step = Math.abs(Number(increment));
      if (step === 1) {
        code += up ? '++' : '--';
      } else {
        code += (up ? ' += ' : ' -= ') + step;
      }
      code += ') {\n' + branch + '}\n';
    } else {
      code = '';
      // Cache non-trivial values to variables to prevent repeated look-ups.
      let startVar = argument0;
      if (!argument0.match(/^\w+$/) && !stringUtils.isNumber(argument0)) {
        startVar =
            Dart.nameDB_.getDistinctName(variable0 + '_start', NameType.VARIABLE);
        code += 'var ' + startVar + ' = ' + argument0 + ';\n';
      }
      let endVar = argument1;
      if (!argument1.match(/^\w+$/) && !stringUtils.isNumber(argument1)) {
        endVar =
            Dart.nameDB_.getDistinctName(variable0 + '_end', NameType.VARIABLE);
        code += 'var ' + endVar + ' = ' + argument1 + ';\n';
      }
      // Determine loop direction at start, in case one of the bounds
      // changes during loop execution.
      const incVar =
          Dart.nameDB_.getDistinctName(variable0 + '_inc', NameType.VARIABLE);
      code += 'num ' + incVar + ' = ';
      if (stringUtils.isNumber(increment)) {
        code += Math.abs(increment) + ';\n';
      } else {
        code += '(' + increment + ').abs();\n';
      }
      code += 'if (' + startVar + ' > ' + endVar + ') {\n';
      code += Dart.INDENT + incVar + ' = -' + incVar + ';\n';
      code += '}\n';
      code += 'for (' + variable0 + ' = ' + startVar + '; ' + incVar +
          ' >= 0 ? ' + variable0 + ' <= ' + endVar + ' : ' + variable0 +
          ' >= ' + endVar + '; ' + variable0 + ' += ' + incVar + ') {\n' +
          branch + '}\n';
    }
    return code;
  };
  
  Dart['controls_forEach'] = function(block) {
    // For each loop.
    const variable0 =
        Dart.nameDB_.getName(block.getFieldValue('VAR'), NameType.VARIABLE);
    const argument0 =
        Dart.valueToCode(block, 'LIST', Dart.ORDER_ASSIGNMENT) || '[]';
    let branch = Dart.statementToCode(block, 'DO');
    branch = Dart.addLoopTrap(branch, block);
    const code =
        'for (var ' + variable0 + ' in ' + argument0 + ') {\n' + branch + '}\n';
    return code;
  };
  
  Dart['controls_flow_statements'] = function(block) {
    // Flow statements: continue, break.
    let xfix = '';
    if (Dart.STATEMENT_PREFIX) {
      // Automatic prefix insertion is switched off for this block.  Add manually.
      xfix += Dart.injectId(Dart.STATEMENT_PREFIX, block);
    }
    if (Dart.STATEMENT_SUFFIX) {
      // Inject any statement suffix here since the regular one at the end
      // will not get executed if the break/continue is triggered.
      xfix += Dart.injectId(Dart.STATEMENT_SUFFIX, block);
    }
    if (Dart.STATEMENT_PREFIX) {
      const loop = block.getSurroundLoop();
      if (loop && !loop.suppressPrefixSuffix) {
        // Inject loop's statement prefix here since the regular one at the end
        // of the loop will not get executed if 'continue' is triggered.
        // In the case of 'break', a prefix is needed due to the loop's suffix.
        xfix += Dart.injectId(Dart.STATEMENT_PREFIX, loop);
      }
    }
    switch (block.getFieldValue('FLOW')) {
      case 'BREAK':
        return xfix + 'break;\n';
      case 'CONTINUE':
        return xfix + 'continue;\n';
    }
    throw Error('Unknown flow statement.');
  };
  