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nix/doc/manual/source/language/identifiers.md
John Ericson eb7d7780b1 Rename doc/manual{src -> source}
This is needed to avoid this
https://github.com/mesonbuild/meson/issues/13774 when we go back to
making our subproject directory `src`.
2024-10-14 11:21:24 -04:00

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Identifiers

An identifier is an ASCII character sequence that:

  • Starts with a letter (a-z, A-Z) or underscore (_)
  • Can contain any number of:
    • Letters (a-z, A-Z)
    • Digits (0-9)
    • Underscores (_)
    • Apostrophes (')
    • Hyphens (-)
  • Is not one of the keywords

Syntax

identifier ~ [A-Za-z_][A-Za-z0-9_'-]*

Names

A name can be written as an identifier or a string literal.

Syntax

nameidentifier | string

Names are used in attribute sets, let bindings, and inherit. Two names are the same if they represent the same sequence of characters, regardless of whether they are written as identifiers or strings.

Keywords

These keywords are reserved and cannot be used as identifiers:

Note

The Nix language evaluator currently allows or to be used as a name in some contexts, for backwards compatibility reasons. Users are advised not to rely on this.

There are long-standing issues with how or is parsed as a name, which can't be resolved without making a breaking change to the language.