Function flag_set

regex/regex-syntax/src/ast/parse.rs:2426–2451

Create an ast::SetFlags. The given pattern should be the full pattern string. The range given should correspond to the byte offsets where the flag set occurs. If negated is true, then the set is interpreted as beginning with a negation.

(
        pat: &str,
        range: Range<usize>,
        flag: ast::Flag,
        negated: bool,
    )

    /// If negated is true, then the set is interpreted as beginning with a
    /// negation.
    fn flag_set(
        pat: &str,
        range: Range<usize>,
        flag: ast::Flag,
        negated: bool,
    ) -> Ast {
        let mut items = vec![
            ast::FlagsItem {
                span: span_range(pat, (range.end - 2)..(range.end - 1)),
                kind: ast::FlagsItemKind::Flag(flag),
            },
        ];
        if negated {
            items.insert(0, ast::FlagsItem {
                span: span_range(pat, (range.start + 2)..(range.end - 2)),
                kind: ast::FlagsItemKind::Negation,
            });
        }
        Ast::Flags(ast::SetFlags {
            span: span_range(pat, range.clone()),
            flags: ast::Flags {
                span: span_range(pat, (range.start + 2)..(range.end - 1)),
                items: items,
            },
        })
    }

    #[test]
    fn parse_nest_limit() {