Help with conflicting mod-rewrite

I want to be able to use foo on both of these mod re-writes this is what I currently have开发者_如何学编程 and is working fine:

#Links to categorys
    RewriteRule foo/(.*)/ foo.php?cat=$1
    RewriteRule foo/(.*) foo.php?cat=$1 

#Links to categorys with pagination    
    RewriteRule fooo/(.*)/(.*)/ foo.php?cat=$1&id=$2
    RewriteRule fooo/(.*)/(.*) foo.php?cat=$1&id=$2

But really want to have this instead:

#Links to categorys
    RewriteRule foo/(.*)/ foo.php?cat=$1
    RewriteRule foo/(.*) foo.php?cat=$1

#Links to categorys with pagination    
    RewriteRule foo/(.*)/(.*)/ foo.php?cat=$1&id=$2
    RewriteRule foo/(.*)/(.*) foo.php?cat=$1&id=$2

as both are relevent to each other (same pages) just a case of additional pagination id's but if I do not have the extra "o" it conflicts and so give me a 404

any help is much appreciated

The problem comes from the fact that this rule:

RewriteRule foo/(.*)

...will match anything that would match your pagination rules, and will do it first. The simplest solution is to just invert the rule order and make a few small changes:

#Links to categorys with pagination
RewriteRule foo/([^/]*)/([^/]+)/? foo.php?cat=$1&id=$2

#Links to categorys
RewriteRule foo/([^/]*)/? foo.php?cat=$1

Additionally, if your script can handle id being passed with no value, you can just condense it all into a single rule:

# Links to categories with optional pagination
RewriteRule foo/([^/]*)(?:/([^/]+))?/? foo.php?cat=$1&id=$2