src/QCheck/Generator.php
public function fmap(callable $f)
    {
        return $this->fmapGen(function (RoseTree $rose) use ($f) {
            return $rose->fmap($f);
        });
    }
public function fmap(callable $f)
    {
        return $this->fmapGen(function (RoseTree $rose) use ($f) {
            return $rose->fmap($f);
        });
    }
public function fmap ( callable $ f ) { return $ this -> fmapGen ( function ( RoseTree $ rose ) use ( $ f ) { return $ rose -> fmap ( $ f ) ; } ) ; }
maps function f over the values produced by this generator

@param callable $f
@return Generator
maps function f over the values produced by this generator