nodeset

Parse, expand, split, and fold node expressions such as a[01-02]r[1-4]n[01-20]. The package also accepts bounded IPv4/IPv6 bracket ranges and CIDR expressions.

The parser keeps leading-zero width, returns deterministic natural ordering, and rejects malformed members instead of silently accepting an empty node. Add is transactional: a failed update does not partially mutate an existing NodeSet.

The package is syntax-focused and does not resolve DNS or validate host reachability. Callers that use the values as shell targets must apply their own host allowlist before execution.

Public helpers:

• NewNodeSet, Expand, and Yield for parsing and iteration;
• Merge for canonical aggregation and ExpandCIDR for one CIDR network;
• Split for balanced worker partitions; non-positive widths return no parts.

The project was originally derived from the Grendel nodeset implementation: https://github.com/ubccr/grendel/nodeset