multiple-catch-block.js

let _try_catch = macro {
  rule { catch ($e:ident) { $body ...} } => {
    {
      let $e = __e;
      $body ...
      return;
    }
  }
  rule { catch ($e:ident if $c:expr) { $body ...} } => {
    {
      let $e = __e;
      if ($c) {
        $body ...
        return;
      }
    }
  }
}

let try = macro {
  rule { { $body ...} $c:_try_catch ... } => {
    try {
      $body ...
    } catch (__e) {
      (function () {
        'use strict';
        $c ...
      })();
    }
  }
}

try {
  // ...
} catch (e if e instanceof TypeError) {
  // ...
} catch (e) {
  // ...
}