How to use lua-types - 10 common examples

export function UnaryExpression(node) {
  switch (node.operator) {
    case 'void':
      return t.binaryExpression('and', this.transform(node.argument), t.nilLiteral());
    case 'delete':
      return t.assignmentStatement([this.transform(node.argument)], [t.nilLiteral()]);
    case '!':
      return t.unaryExpression('not', this.transform(node.argument));
    case '+':
      return t.callExpression(t.identifier('tonumber'), [this.transform(node.argument)]);
    case '-':
    case '~':
      return t.unaryExpression(node.operator, this.transform(node.argument));
    default:
      // FIXME: Use path.buildCodeFrameError
      throw new Error(`${node.operator} is unsupported unary operator`);
  }
}

export function ForOfStatement(node) {
  const variable = bt.isVariableDeclaration(node.left)
    ? this.transform(node.left.declarations[0].id)
    : this.transform(node.left);
  const helper = t.memberExpression(t.identifier('Reflect'), ':', t.identifier('__forOf'));

  let uid = node[FOR_OF_UID];
  // TODO: Apply visitor before transform in testing
  if (uid == null && process.env.NODE_ENV === 'test') uid = bt.identifier('_');
  if (uid == null) throw new Error('UID not found for ForOfStatement transform');

  return t.forGenericStatement(
    [this.transform(uid), variable],
    [t.callExpression(helper, [this.transform(node.right)])],
    this.transformBlock(node.body),
  );
}

export function ForOfStatement(node) {
  const variable = bt.isVariableDeclaration(node.left)
    ? this.transform(node.left.declarations[0].id)
    : this.transform(node.left);
  const helper = t.memberExpression(t.identifier('Reflect'), ':', t.identifier('__forOf'));

  let uid = node[FOR_OF_UID];
  // TODO: Apply visitor before transform in testing
  if (uid == null && process.env.NODE_ENV === 'test') uid = bt.identifier('_');
  if (uid == null) throw new Error('UID not found for ForOfStatement transform');

  return t.forGenericStatement(
    [this.transform(uid), variable],
    [t.callExpression(helper, [this.transform(node.right)])],
    this.transformBlock(node.body),
  );
}

export function CallExpression(node) {
  if (bt.isIdentifier(node.callee, { name: '__lua' }) && node.arguments.length === 1) {
    const argument = node.arguments[0];
    // TODO: Use path.evaluate, ref: https://github.com/babel/babel/blob/6.x/packages/babel-plugin-transform-eval/src/index.js
    if (bt.isStringLiteral(argument)) {
      return t.luaRaw(argument.value);
    }
  }

  return t.callExpression(this.transform(node.callee), this.transformList(node.arguments));
}

export function UpdateExpression(node, parent) {
  if (!bt.isExpressionStatement(parent)) {
    // FIXME: Use path.buildCodeFrameError
    throw new Error("UpdateExpression's not in ExpressionStatement's are not supported.");
  }
  if (node.operator !== '++' && node.operator !== '--') {
    // FIXME: Use path.buildCodeFrameError
    throw new Error(`Invalid UpdateExpression operator ${node.operator}`);
  }

  const right = t.binaryExpression(
    node.operator === '++' ? '+' : '-',
    this.transform(node.argument),
    t.numericLiteral(1),
  );
  return t.assignmentStatement([this.transform(node.argument)], [right]);
}

export function UnaryExpression(node) {
  switch (node.operator) {
    case 'void':
      return t.binaryExpression('and', this.transform(node.argument), t.nilLiteral());
    case 'delete':
      return t.assignmentStatement([this.transform(node.argument)], [t.nilLiteral()]);
    case '!':
      return t.unaryExpression('not', this.transform(node.argument));
    case '+':
      return t.callExpression(t.identifier('tonumber'), [this.transform(node.argument)]);
    case '-':
    case '~':
      return t.unaryExpression(node.operator, this.transform(node.argument));
    default:
      // FIXME: Use path.buildCodeFrameError
      throw new Error(`${node.operator} is unsupported unary operator`);
  }
}

export function LogicalExpression(node) {
  if (node.operator !== '&&' && node.operator !== '||') {
    // FIXME: Use path.buildCodeFrameError
    throw new Error(`${node.operator} is unsupported logical operator`);
  }
  const operator = node.operator === '&&' ? 'and' : 'or';
  return t.binaryExpression(operator, this.transform(node.left), this.transform(node.right));
}

export function UnaryExpression(node) {
  switch (node.operator) {
    case 'void':
      return t.binaryExpression('and', this.transform(node.argument), t.nilLiteral());
    case 'delete':
      return t.assignmentStatement([this.transform(node.argument)], [t.nilLiteral()]);
    case '!':
      return t.unaryExpression('not', this.transform(node.argument));
    case '+':
      return t.callExpression(t.identifier('tonumber'), [this.transform(node.argument)]);
    case '-':
    case '~':
      return t.unaryExpression(node.operator, this.transform(node.argument));
    default:
      // FIXME: Use path.buildCodeFrameError
      throw new Error(`${node.operator} is unsupported unary operator`);
  }
}

return function FunctionHandler(node) {
    const body = this.transformBlock(node.body);
    const restParam = node.params.find(param => bt.isRestElement(param));
    if (restParam) {
      body.unshift(
        t.localStatement(
          [restParam.argument],
          [t.tableConstructorExpression([t.tableValue(t.varargLiteral())])],
        ),
      );
    }

    return t.functionStatement(
      isExp ? null : this.transform(node.id),
      this.transformList(node.params),
      // Simulate module structure for declaration
      !isExp,
      body,
    );
  };
}

export function UpdateExpression(node, parent) {
  if (!bt.isExpressionStatement(parent)) {
    // FIXME: Use path.buildCodeFrameError
    throw new Error("UpdateExpression's not in ExpressionStatement's are not supported.");
  }
  if (node.operator !== '++' && node.operator !== '--') {
    // FIXME: Use path.buildCodeFrameError
    throw new Error(`Invalid UpdateExpression operator ${node.operator}`);
  }

  const right = t.binaryExpression(
    node.operator === '++' ? '+' : '-',
    this.transform(node.argument),
    t.numericLiteral(1),
  );
  return t.assignmentStatement([this.transform(node.argument)], [right]);
}