function bindLocal(env, scope, name, value) {
  scope.localPresent[name] = true;
  scope.locals[name] = value;
}
Host Hook: bindLocal

  @param {Environment} env
  @param {Scope} scope
  @param {String} name
  @param {any} value

  Corresponds to entering a template with block arguments.

  This hook is invoked when a local variable for a scope has been provided.

  The host must ensure that child scopes reflect the change in future calls
  to the `get` hook.