exist() function

[Lorenzo M. Catucci]

Now, I learnt about exist, and can do something like this:

function a=f(x)
a=2*x;
end

and then 

exist("f")
2

(sorry, no cut and paste on this dumb terminal)

Now, what I'd need is to know if the string I'd pass to eval could be
parsed, like in
exist("f(y)")
which instead returns with an ugly 0...

maybe I could try and look at some string editing function, but it looks
ugly...

Yours,

lorenzo