Custom patterns can have additional variables. These variables works like query variables.

class p(@In @Out Node a, int var1, Object var2) ( a > Node(var1, var2) )

If these variables are set with query variables when called by the query, their value will be matched by the query matching. For instance:

class p(@In @Out Node a, float var) ( a > A(var) )
void rule()[
 Node -p(x)-> ::>; // is equivalent to
 Node > A(x) ::>; // thus, x is bound to the value the same way.
 Node -p(5)-> ::>; // is also possible to query for a specific value
]