Function validate

std/re/src/main/mod.rs:184–195

Reject lookbehind whose width is not fixed, which the engine cannot run. */

(node: &Node)

/* Reject lookbehind whose width is not fixed, which the engine cannot run. */
fn validate(node: &Node) -> Result<(), ReError> {
    match node {
        Node::Look { node, behind: true, .. } => {
            if fixed_len(node).is_none() { return Err(ReError::Syntax(String::from("lookbehind requires fixed width"))); }
            validate(node)
        }
        Node::Look { node, .. } => validate(node),
        Node::Concat(v) | Node::Alt(v) => { for n in v { validate(n)?; } Ok(()) }
        Node::Group { node, .. } | Node::NonCap(node) | Node::Repeat { node, .. } => validate(node),
        _ => Ok(()),
    }
}