Function text_charAt

packages/blockly/generators/dart/text.ts:97–157

(
  block: Block,
  generator: DartGenerator,
)

}

export function text_charAt(
  block: Block,
  generator: DartGenerator,
): [string, Order] {
  // Get letter at index.
  // Note: Until January 2013 this block did not have the WHERE input.
  const where = block.getFieldValue('WHERE') || 'FROM_START';
  const textOrder =
    where === 'FIRST' || where === 'FROM_START'
      ? Order.UNARY_POSTFIX
      : Order.NONE;
  const text = generator.valueToCode(block, 'VALUE', textOrder) || "''";
  let at;
  switch (where) {
    case 'FIRST': {
      const code = text + '[0]';
      return [code, Order.UNARY_POSTFIX];
    }
    case 'FROM_START': {
      at = generator.getAdjusted(block, 'AT');
      const code = text + '[' + at + ']';
      return [code, Order.UNARY_POSTFIX];
    }
    case 'LAST':
    case 'FROM_END': {
      if (where === 'LAST') {
        at = 1;
      } else {
        at = generator.getAdjusted(block, 'AT', 1);
      }
      const functionName = generator.provideFunction_(
        'text_get_from_end',
        `
String ${generator.FUNCTION_NAME_PLACEHOLDER_}(String text, num x) {
  return text[text.length - x];
}
`,
      );
      const code = `${functionName}(${text}, ${at})`;
      return [code, Order.UNARY_POSTFIX];
    }
    case 'RANDOM': {
      // TODO(#7600): find better approach than casting to any to override
      // CodeGenerator declaring .definitions protected.
      (generator as AnyDuringMigration).definitions_['import_dart_math'] =
        "import 'dart:math' as Math;";
      const functionName = generator.provideFunction_(
        'text_random_letter',
        `
String ${generator.FUNCTION_NAME_PLACEHOLDER_}(String text) {
  int x = new Math.Random().nextInt(text.length);
  return text[x];
}
`,
      );
      const code = functionName + '(' + text + ')';
      return [code, Order.UNARY_POSTFIX];
    }