FileName

A file's name that every common file system takes: report.pdf.

Use it for a download's or an upload's name. For a whole path, use FilePath.

Shape

One value, held as text in one set form, with no parts: CONSOLE.txt.

Example

FileName("report.pdf")

FileName(raw) checks the text, and text that isn't one breaks the format rule.

text.parse(raw, as: FileName) reads one from text that comes from outside. Text that isn't one at all fails malformed, such as notes/today.txt, notes\today.txt or what?.txt.

Good to know

• It refuses /, \ and Windows' reserved names, and goes up to 255 bytes. So a name from an upload can't reach another folder.
• == tells you whether two are the same. < and list.sort_by don't take it.

In JSON

A string, in a request, a response or json.write:

"report.pdf""Résumé 2026.docx"".gitignore"

Details