use crate::common::*; pub struct Functions<'a> { stack: Vec<&'a Expression<'a>>, } impl<'a> Iterator for Functions<'a> { type Item = (&'a Token<'a>, usize); fn next(&mut self) -> Option { match self.stack.pop() { None | Some(Expression::String { .. }) | Some(Expression::Backtick { .. }) | Some(Expression::Variable { .. }) => None, Some(Expression::Call { token, arguments, .. }) => Some((token, arguments.len())), Some(Expression::Concatination { lhs, rhs }) => { self.stack.push(lhs); self.stack.push(rhs); self.next() } Some(Expression::Group { expression }) => { self.stack.push(expression); self.next() } } } }