Copyright	(c) 2013 Bryan O'Sullivan (c) 2010 Johan Tibell
License	BSD-style (see LICENSE)
Maintainer	Johan Tibell <johan.tibell@gmail.com>
Stability	experimental
Portability	portable to Hugs and GHC
Safe Haskell	Trustworthy
Language	Haskell98

Data.Text.Lazy.Builder

Contents

The Builder type
Constructing Builders
Flushing the buffer state

Description

Efficient construction of lazy Text values. The principal operations on a Builder are singleton, fromText, and fromLazyText, which construct new builders, and mappend, which concatenates two builders.

To get maximum performance when building lazy Text values using a builder, associate mappend calls to the right. For example, prefer

singleton 'a' `mappend` (singleton 'b' `mappend` singleton 'c')

to

singleton 'a' `mappend` singleton 'b' `mappend` singleton 'c'

as the latter associates mappend to the left. Or, equivalently, prefer

singleton 'a' <> singleton 'b' <> singleton 'c'

since the <> from recent versions of Monoid associates to the right.

Synopsis

The Builder type

data Builder #

A Builder is an efficient way to build lazy Text values. There are several functions for constructing builders, but only one to inspect them: to extract any data, you have to turn them into lazy Text values using toLazyText.

Internally, a builder constructs a lazy Text by filling arrays piece by piece. As each buffer is filled, it is 'popped' off, to become a new chunk of the resulting lazy Text. All this is hidden from the user of the Builder.

Instances

Eq Builder #
Methods (==) :: Builder -> Builder -> Bool # (/=) :: Builder -> Builder -> Bool #
Ord Builder #
Methods compare :: Builder -> Builder -> Ordering # (<) :: Builder -> Builder -> Bool # (<=) :: Builder -> Builder -> Bool # (>) :: Builder -> Builder -> Bool # (>=) :: Builder -> Builder -> Bool # max :: Builder -> Builder -> Builder # min :: Builder -> Builder -> Builder #
Show Builder #
Methods showsPrec :: Int -> Builder -> ShowS # show :: Builder -> String # showList :: [Builder] -> ShowS #
IsString Builder #
Methods fromString :: String -> Builder #
Semigroup Builder #
Methods (<>) :: Builder -> Builder -> Builder # sconcat :: NonEmpty Builder -> Builder # stimes :: Integral b => b -> Builder -> Builder #
Monoid Builder #
Methods mempty :: Builder # mappend :: Builder -> Builder -> Builder # mconcat :: [Builder] -> Builder #

toLazyText :: Builder -> Text #

O(n). Extract a lazy Text from a Builder with a default buffer size. The construction work takes place if and when the relevant part of the lazy Text is demanded.

toLazyTextWith :: Int -> Builder -> Text #

O(n). Extract a lazy Text from a Builder, using the given size for the initial buffer. The construction work takes place if and when the relevant part of the lazy Text is demanded.

If the initial buffer is too small to hold all data, subsequent buffers will be the default buffer size.

Constructing Builders

singleton :: Char -> Builder #

O(1). A Builder taking a single character, satisfying

```
toLazyText (singleton c) = singleton c
```

fromText :: Text -> Builder #

O(1). A Builder taking a Text, satisfying

toLazyText (fromText t) = fromChunks [t]

fromLazyText :: Text -> Builder #

O(1). A Builder taking a lazy Text, satisfying

```
toLazyText (fromLazyText t) = t
```

fromString :: String -> Builder #

O(1). A Builder taking a String, satisfying

toLazyText (fromString s) = fromChunks [S.pack s]

Flushing the buffer state

flush :: Builder #

O(1). Pop the strict Text we have constructed so far, if any, yielding a new chunk in the result lazy Text.