head

builtins.head

Primop

Docs pulled from | This Revision | about 11 hours ago

Takes 1 arguments

list

Return the first element of a list; abort evaluation if the argument isn’t a list or is an empty list. You can test whether a list is empty by comparing it with [].

This function is not defined in a .nix file. It is likely a builtins function or an alias of a builtins function. builtins functions are predefined functions provided by Nix.

Noogle detected

Aliases

lib.head
lib.lists.head
lib.strings.head

Detected Type

head :: [a] -> a

Implementation

This function is implemented in c++ and is part of the native nix runtime.