public function bindIf( $abstract, $concrete = NULL, $shared = FALSE )
    {
        if ( !$this->bound( $abstract ) )
        {
            $this->bind( $abstract, $concrete, $shared );
        }

        return $this;
    }
public function bindIf( $abstract, $concrete = NULL, $shared = FALSE )
    {
        if ( !$this->bound( $abstract ) )
        {
            $this->bind( $abstract, $concrete, $shared );
        }

        return $this;
    }
public function bindIf ( $ abstract , $ concrete = NULL , $ shared = FALSE ) { if ( ! $ this -> bound ( $ abstract ) ) { $ this -> bind ( $ abstract , $ concrete , $ shared ) ; } return $ this ; }
Register a binding if it hasn't already been registered.

@param  string              $abstract
@param  Closure|string|null $concrete
@param  bool                $shared

@return IContainer
Register a binding if it hasn t already been registered .