b2285ce0e0
Just's first parser performed both parsing, i.e the transformation of a token stream according to the language grammar, and a number of consistency checks and analysis passes. This made parsing and analysis quite complex, so this diff introduces a new, much cleaner `Parser`, and moves existing analysis into a dedicated `Analyzer`.
35 lines
963 B
Rust
35 lines
963 B
Rust
use crate::common::*;
|
|
|
|
pub(crate) struct Variables<'expression, 'src> {
|
|
stack: Vec<&'expression Expression<'src>>,
|
|
}
|
|
|
|
impl<'expression, 'src> Variables<'expression, 'src> {
|
|
pub(crate) fn new(root: &'expression Expression<'src>) -> Variables<'expression, 'src> {
|
|
Variables { stack: vec![root] }
|
|
}
|
|
}
|
|
|
|
impl<'expression, 'src> Iterator for Variables<'expression, 'src> {
|
|
type Item = Token<'src>;
|
|
|
|
fn next(&mut self) -> Option<Token<'src>> {
|
|
match self.stack.pop() {
|
|
None
|
|
| Some(Expression::StringLiteral { .. })
|
|
| Some(Expression::Backtick { .. })
|
|
| Some(Expression::Call { .. }) => None,
|
|
Some(Expression::Variable { name, .. }) => Some(name.token()),
|
|
Some(Expression::Concatination { lhs, rhs }) => {
|
|
self.stack.push(lhs);
|
|
self.stack.push(rhs);
|
|
self.next()
|
|
}
|
|
Some(Expression::Group { contents }) => {
|
|
self.stack.push(contents);
|
|
self.next()
|
|
}
|
|
}
|
|
}
|
|
}
|