original_string: public function singleton($id, callable $resolver)
      {
          $this->innerSet($id, $resolver);
          unset($this->resolved[$id]);
          $this->singletons[$id] = true;
          return $this;
      }
code: public function singleton($id, callable $resolver)
      {
          $this->innerSet($id, $resolver);
          unset($this->resolved[$id]);
          $this->singletons[$id] = true;
          return $this;
      }
code_tokens: public function singleton ( $ id , callable $ resolver ) { $ this -> innerSet ( $ id , $ resolver ) ; unset ( $ this -> resolved [ $ id ] ) ; $ this -> singletons [ $ id ] = true ; return $ this ; }
docstring: Sets a resolver for entry of the container by its identifier as singleton.
  
  @param string $id Identifier of the entry to look for.
  @param callable $resolver Function that resolves the entry and returns it.
  
  @return $this.
docstring_tokens: Sets a resolver for entry of the container by its identifier as singleton .