head -package:hedgehog
The first element of a non-empty structure.
>>> head (1 :| [2, 3, 4])
1
Extract the first element of the stream.
O(1) Extract the first element of a ByteString, which must be
non-empty. An exception will be thrown in the case of an empty
ByteString.
This is a partial function, consider using
uncons instead.
O(1) Extract the first element of a ByteString, which must be
non-empty.
O(1) Extract the first element of a ByteString, which must be
non-empty.
This is a partial function, consider using
uncons instead.
O(1) Extract the first element of a ShortByteString, which must
be non-empty. An exception will be thrown in the case of an empty
ShortByteString.
This is a partial function, consider using
uncons instead.
O(1) Returns the first character of a
Text, which must
be non-empty. This is a partial function, consider using
uncons
instead.
O(1) Returns the first character of a
Stream
Char, which must be non-empty. This is a partial function,
consider using
uncons.
Properties
head . stream = head
First element of the
Bundle or error if empty
First element of the
Bundle or error if empty
Take a single value from the stream, if available.
Take a single value from the stream, if available.
Subject to fusion
Since 0.3.0
Combinator for the
<head> element.
Example:
head $ span $ toHtml "foo"
Result:
<head><span>foo</span></head>
Return the next byte from the stream, if available.
Since 0.3.0
Retrieve the first element from a
Producer