Debian.Control.Text

Types

newtype Control' a

Constructors

Control

Fields

unControl :: [Paragraph' a]

Instances

Eq a => Eq (Control' a)

Ord a => Ord (Control' a)

Read a => Read (Control' a)

Show a => Show (Control' a)

(ControlFunctions a, Pretty (PP a)) => Pretty (Control' a)

This may have bad performance issues (dsf: Whoever wrote this comment should have explained why.)

newtype Paragraph' a

Constructors

Paragraph [Field' a]

Instances

Eq a => Eq (Paragraph' a)

Ord a => Ord (Paragraph' a)

Read a => Read (Paragraph' a)

Show a => Show (Paragraph' a)

(ControlFunctions a, Pretty (PP a)) => Pretty (Paragraph' a)

data Field' a

NOTE: we do not strip the leading or trailing whitespace in the name or value

Constructors

Field (a, a)

Comment a

Lines beginning with #

Instances

Eq a => Eq (Field' a)

Ord a => Ord (Field' a)

Read a => Read (Field' a)

Show a => Show (Field' a)

(ControlFunctions a, Pretty (PP a)) => Pretty (Field' a)

type Control = Control' Text

type Paragraph = Paragraph' Text

type Field = Field' Text

parseFromFile p filePath runs a string parser p on the input read from filePath using readFile. Returns either a ParseError (Left) or a value of type a (Right).

 main    = do{ result <- parseFromFile numbers "digits.txt"
             ; case result of
                 Left err  -> print err
                 Right xs  -> print (sum xs)
             }

class ControlFunctions a where

Methods

parseControlFromFile :: FilePath -> IO (Either ParseError (Control' a))

parseControlFromFile filepath is a simple wrapper function that parses filepath using pControl

parseControlFromHandle :: String -> Handle -> IO (Either ParseError (Control' a))

parseControlFromHandle sourceName handle - sourceName is only used for error reporting

parseControl :: String -> a -> Either ParseError (Control' a)

parseControlFromString sourceName text - sourceName is only used for error reporting

lookupP :: String -> Paragraph' a -> Maybe (Field' a)

lookupP fieldName paragraph looks up a Field in a Paragraph. N.B. trailing and leading whitespace is not stripped.

stripWS :: a -> a

Strip the trailing and leading space and tab characters from a string. Folded whitespace is not unfolded. This should probably be moved to someplace more general purpose.

protectFieldText :: a -> a

Protect field value text so the parser doesn't split it into multiple fields or paragraphs. This must modify all field text to enforce two conditions: (1) All lines other than the initial one must begin with a space or a tab, and (2) the trailing white space must not contain newlines. This is called before pretty printing to prevent the parser from misinterpreting field text as multiple fields or paragraphs.

asString :: a -> String

Control File Parser

Helper Functions

mergeControls :: [Control' a] -> Control' a

fieldValue :: ControlFunctions a => String -> Paragraph' a -> Maybe a

removeField :: Eq a => a -> Paragraph' a -> Paragraph' a

prependFields :: [Field' a] -> Paragraph' a -> Paragraph' a

appendFields :: [Field' a] -> Paragraph' a -> Paragraph' a

renameField :: Eq a => a -> a -> Paragraph' a -> Paragraph' a

modifyField :: Eq a => a -> (a -> a) -> Paragraph' a -> Paragraph' a

raiseFields :: Eq a => (a -> Bool) -> Paragraph' a -> Paragraph' a

Move selected fields to the beginning of a paragraph.

decodeControl :: Control -> Control

decodeParagraph :: Paragraph -> Paragraph

decodeField :: Field' ByteString -> Field' Text