phpdoc commenter

Has anyone seen a script or app that will parse PHP files and add phpdoc comments in the PHP file when it encounters a function or class? I know it won't be fool-proof, but it could at least add a block comment with required parameters and ascertain the function arguments and return value to be added in the block comment. Shouldn't be a difficult script to write, but maybe there is a good solution out there. TIA -Shawn