I think bound and free usually refers to *occurrences* of variables in an expression. In your example you only have occurrences of g and c, but there may be more hiding in the ... part. A variable is free in an expression if the path from the root to the variable does not include a binder for the variable. In your example, g is bound in the whole expression, but free in the sub-expression g c. However, I think that "bound" is also sometimes used to mean "in scope", and this seems to be mainlyyour interpretation. When you say "y is bound in g", you really mean that y is in scope in *the body* of g (i.e. in the ...) / Emil Den 2014-09-18 08:49, Jan Stolarek skrev:
Hi *,
I have a simple question about terminology regarding bound and free variables. Assume I have:
let f x = let g y = ... in g c in ...
Now: - `c` is free in `g` and `f` - `y` is bound in `g` - `x` is free in `g`. - `x` is bound in `f`
What about `y` in `f`? Is it also bound in `f`? If so then it certainly is bound in a different way that `x`. Is there a terminology that allows to distinguish these different forms of bound variables?
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