[Vala] Lambda expression with arguments?

["Michel Salim" <michel sylvan gmail com>]

Hello,

All the examples on the Vala site involves using lambda expressions as
signal handlers. The expressions there take no parameters and return
void.

Getting a lambda expression to return something seems straightforward,
but how does one write a lambda expression that takes arguments? Can
the types of the parameters and return value be specified?

Thanks,

-- 
Michel Salim