1 way: to copy directory structure of core block to local code pool and copy core block file. For example :
app/code/local/Mage/Catalog/Block/Navigation.php. And then and needed methods.
2 way: Configure rewrite in this way:
<global> <blocks> <catalog> <rewrite> <navigation>Vendor_Catalog_Block_Navigation</navigation> </rewrite> </catalog> </blocks> </global>
And then extend my class from magento core class.
Which way is more correct?