Manipulate lazy ByteStrings using Char operations. All Chars will be truncated to 8 bits. It can be expected that these functions will run at identical speeds to their Word8 equivalents in Data.ByteString.Lazy.

This module is intended to be imported qualified, to avoid name clashes with Prelude functions. eg.

 import qualified Data.ByteString.Lazy.Char8 as C

O(1) Unlike cons, cons is strict in the ByteString that we are consing onto. More precisely, it forces the head and the first chunk. It does this because, for space efficiency, it may coalesce the new byte onto the first 'chunk' rather than starting a new 'chunk'.

So that means you can't use a lazy recursive contruction like this:

 let xs = cons\' c xs in xs

You can however use cons, as well as repeat and cycle, to build infinite lazy ByteStrings.

scanl is similar to foldl, but returns a list of successive reduced values from the left. This function will fuse.

 scanl f z [x1, x2, ...] == [z, z `f` x1, (z `f` x1) `f` x2, ...]

Note that

 last (scanl f z xs) == foldl f z xs.

iterate f x returns an infinite ByteString of repeated applications of f to x:

 iterate f x == [x, f x, f (f x), ...]

The group function takes a ByteString and returns a list of ByteStrings such that the concatenation of the result is equal to the argument. Moreover, each sublist in the result contains only equal elements. For example,

 group "Mississippi" = ["M","i","ss","i","ss","i","pp","i"]

It is a special case of groupBy, which allows the programmer to supply their own equality test.

O(n) Break a ByteString into pieces separated by the byte argument, consuming the delimiter. I.e.

 split '\n' "a\nb\nd\ne" == ["a","b","d","e"]
 split 'a'  "aXaXaXa"    == ["","X","X","X"]
 split 'x'  "x"          == ["",""]

and

 intercalate [c] . split c == id
 split == splitWith . (==)

As for all splitting functions in this library, this function does not copy the substrings, it just constructs new ByteStrings that are slices of the original.

O(n) Splits a ByteString into components delimited by separators, where the predicate returns True for a separator element. The resulting components do not contain the separators. Two adjacent separators result in an empty component in the output. eg.

 splitWith (=='a') "aabbaca" == ["","","bb","c",""]

words breaks a ByteString up into a list of words, which were delimited by Chars representing white space. And

 tokens isSpace = words

count returns the number of times its argument appears in the ByteString

 count      == length . elemIndices
 count '\n' == length . lines

But more efficiently than using length on the intermediate list.