Kernel.hd
You're seeing just the function
hd
, go back to Kernel module for more information.
Specs
hd(nonempty_maybe_improper_list(elem, any())) :: elem when elem: term()
Returns the head of a list. Raises ArgumentError
if the list is empty.
It works with improper lists.
Allowed in guard tests. Inlined by the compiler.
Examples
hd([1, 2, 3, 4])
#=> 1
hd([1 | 2])
#=> 1
Giving it an empty list raises:
tl([])
#=> ** (ArgumentError) argument error