Hugo currently supports encoding some options in filenames, e.g.:

• mypage.en.md — content file with language set.
• list.en.rss.html — layout file with both language and output format set.

But the above does not allow us to set role or version, as that would lead to ambiguity.

Wrapper syntax

Hugo already supports a wrapper syntax using underscores for custom identifiers in content filenames, e.g. mypage._myidentifier_.md. The wrapped segment is treated as an opaque block by the filename parser, which means dots and other characters inside it are not interpreted as segment delimiters. The identifier itself is currently ignored, but it allows multiple content files to share the same logical name while defining different sites in front matter.

Prefix identifiers

This proposal builds on the wrapper syntax by giving the wrapped segments a structured meaning through prefix identifiers. For example, mypage._language_en_.md would set the language to en. Multiple identifiers can be combined, e.g.:

mypage._language_en_._role_admin_.md

For identifiers that support multiple values, the same prefix can be repeated:

mypage._role_guest_._role_admin_.md

The wrapper syntax also allows values that contain dots, which would otherwise be ambiguous:

mypage._version_v1.0.0_._language_en_.md

The existing mypage.en.md format would still be supported.