| Copyright | (c) Daan Leijen 1999-2001 (c) Paolo Martini 2007 | 
|---|---|
| License | BSD-style (see the LICENSE file) | 
| Maintainer | aslatter@gmail.com | 
| Stability | provisional | 
| Portability | portable | 
| Safe Haskell | Safe | 
| Language | Haskell2010 | 
Text.Parsec
Description
This module includes everything you need to get started writing a parser.
By default this module is set up to parse character data. If you'd like to parse the result of your own tokenizer you should start with the following imports:
import Text.Parsec.Prim import Text.Parsec.Combinator
Then you can implement your own version of satisfy on top of the tokenPrim
primitive.
Synopsis
- data ParsecT s u m a
- type Parsec s u = ParsecT s u Identity
- token :: Stream s Identity t => (t -> String) -> (t -> SourcePos) -> (t -> Maybe a) -> Parsec s u a
- tokens :: (Stream s m t, Eq t) => ([t] -> String) -> (SourcePos -> [t] -> SourcePos) -> [t] -> ParsecT s u m [t]
- runParserT :: Stream s m t => ParsecT s u m a -> u -> SourceName -> s -> m (Either ParseError a)
- runParser :: Stream s Identity t => Parsec s u a -> u -> SourceName -> s -> Either ParseError a
- parse :: Stream s Identity t => Parsec s () a -> SourceName -> s -> Either ParseError a
- parseTest :: (Stream s Identity t, Show a) => Parsec s () a -> s -> IO ()
- getPosition :: Monad m => ParsecT s u m SourcePos
- getInput :: Monad m => ParsecT s u m s
- getState :: Monad m => ParsecT s u m u
- putState :: Monad m => u -> ParsecT s u m ()
- modifyState :: Monad m => (u -> u) -> ParsecT s u m ()
- (<|>) :: ParsecT s u m a -> ParsecT s u m a -> ParsecT s u m a
- (<?>) :: ParsecT s u m a -> String -> ParsecT s u m a
- label :: ParsecT s u m a -> String -> ParsecT s u m a
- labels :: ParsecT s u m a -> [String] -> ParsecT s u m a
- try :: ParsecT s u m a -> ParsecT s u m a
- unexpected :: Stream s m t => String -> ParsecT s u m a
- choice :: Stream s m t => [ParsecT s u m a] -> ParsecT s u m a
- many :: ParsecT s u m a -> ParsecT s u m [a]
- many1 :: Stream s m t => ParsecT s u m a -> ParsecT s u m [a]
- skipMany :: ParsecT s u m a -> ParsecT s u m ()
- skipMany1 :: Stream s m t => ParsecT s u m a -> ParsecT s u m ()
- count :: Stream s m t => Int -> ParsecT s u m a -> ParsecT s u m [a]
- between :: Stream s m t => ParsecT s u m open -> ParsecT s u m close -> ParsecT s u m a -> ParsecT s u m a
- option :: Stream s m t => a -> ParsecT s u m a -> ParsecT s u m a
- optionMaybe :: Stream s m t => ParsecT s u m a -> ParsecT s u m (Maybe a)
- optional :: Stream s m t => ParsecT s u m a -> ParsecT s u m ()
- sepBy :: Stream s m t => ParsecT s u m a -> ParsecT s u m sep -> ParsecT s u m [a]
- sepBy1 :: Stream s m t => ParsecT s u m a -> ParsecT s u m sep -> ParsecT s u m [a]
- endBy :: Stream s m t => ParsecT s u m a -> ParsecT s u m sep -> ParsecT s u m [a]
- endBy1 :: Stream s m t => ParsecT s u m a -> ParsecT s u m sep -> ParsecT s u m [a]
- sepEndBy :: Stream s m t => ParsecT s u m a -> ParsecT s u m sep -> ParsecT s u m [a]
- sepEndBy1 :: Stream s m t => ParsecT s u m a -> ParsecT s u m sep -> ParsecT s u m [a]
- chainl :: Stream s m t => ParsecT s u m a -> ParsecT s u m (a -> a -> a) -> a -> ParsecT s u m a
- chainl1 :: Stream s m t => ParsecT s u m a -> ParsecT s u m (a -> a -> a) -> ParsecT s u m a
- chainr :: Stream s m t => ParsecT s u m a -> ParsecT s u m (a -> a -> a) -> a -> ParsecT s u m a
- chainr1 :: Stream s m t => ParsecT s u m a -> ParsecT s u m (a -> a -> a) -> ParsecT s u m a
- eof :: (Stream s m t, Show t) => ParsecT s u m ()
- notFollowedBy :: (Stream s m t, Show a) => ParsecT s u m a -> ParsecT s u m ()
- manyTill :: Stream s m t => ParsecT s u m a -> ParsecT s u m end -> ParsecT s u m [a]
- lookAhead :: Stream s m t => ParsecT s u m a -> ParsecT s u m a
- anyToken :: (Stream s m t, Show t) => ParsecT s u m t
- module Text.Parsec.Char
- data ParseError
- errorPos :: ParseError -> SourcePos
- data SourcePos
- type SourceName = String
- type Line = Int
- type Column = Int
- sourceName :: SourcePos -> SourceName
- sourceLine :: SourcePos -> Line
- sourceColumn :: SourcePos -> Column
- incSourceLine :: SourcePos -> Line -> SourcePos
- incSourceColumn :: SourcePos -> Column -> SourcePos
- setSourceLine :: SourcePos -> Line -> SourcePos
- setSourceColumn :: SourcePos -> Column -> SourcePos
- setSourceName :: SourcePos -> SourceName -> SourcePos
- parserTrace :: (Show t, Stream s m t) => String -> ParsecT s u m ()
- parserTraced :: (Stream s m t, Show t) => String -> ParsecT s u m b -> ParsecT s u m b
- manyAccum :: (a -> [a] -> [a]) -> ParsecT s u m a -> ParsecT s u m [a]
- tokenPrim :: Stream s m t => (t -> String) -> (SourcePos -> t -> s -> SourcePos) -> (t -> Maybe a) -> ParsecT s u m a
- tokenPrimEx :: Stream s m t => (t -> String) -> (SourcePos -> t -> s -> SourcePos) -> Maybe (SourcePos -> t -> s -> u -> u) -> (t -> Maybe a) -> ParsecT s u m a
- runPT :: Stream s m t => ParsecT s u m a -> u -> SourceName -> s -> m (Either ParseError a)
- unknownError :: State s u -> ParseError
- sysUnExpectError :: String -> SourcePos -> Reply s u a
- mergeErrorReply :: ParseError -> Reply s u a -> Reply s u a
- getParserState :: Monad m => ParsecT s u m (State s u)
- setParserState :: Monad m => State s u -> ParsecT s u m (State s u)
- updateParserState :: (State s u -> State s u) -> ParsecT s u m (State s u)
- class Monad m => Stream s m t | s -> t where
- runParsecT :: Monad m => ParsecT s u m a -> State s u -> m (Consumed (m (Reply s u a)))
- mkPT :: Monad m => (State s u -> m (Consumed (m (Reply s u a)))) -> ParsecT s u m a
- runP :: Stream s Identity t => Parsec s u a -> u -> SourceName -> s -> Either ParseError a
- data Consumed a
- data Reply s u a- = Ok a !(State s u) ParseError
- | Error ParseError
 
- data State s u = State {- stateInput :: s
- statePos :: !SourcePos
- stateUser :: !u
 
- setPosition :: Monad m => SourcePos -> ParsecT s u m ()
- setInput :: Monad m => s -> ParsecT s u m ()
- setState :: Monad m => u -> ParsecT s u m ()
- updateState :: Monad m => (u -> u) -> ParsecT s u m ()
- parsecMap :: (a -> b) -> ParsecT s u m a -> ParsecT s u m b
- parserReturn :: a -> ParsecT s u m a
- parserBind :: ParsecT s u m a -> (a -> ParsecT s u m b) -> ParsecT s u m b
- parserFail :: String -> ParsecT s u m a
- parserZero :: ParsecT s u m a
- parserPlus :: ParsecT s u m a -> ParsecT s u m a -> ParsecT s u m a
Parsers
ParserT monad transformer and Parser type
ParsecT s u m a is a parser with stream type s, user state type u,
 underlying monad m and return type a.  Parsec is strict in the user state.
 If this is undesirable, simply use a data type like data Box a = Box a and
 the state type Box YourStateType to add a level of indirection.
Instances
| MonadError e m => MonadError e (ParsecT s u m) # | |
| Defined in Text.Parsec.Prim Methods throwError :: e -> ParsecT s u m a Source # catchError :: ParsecT s u m a -> (e -> ParsecT s u m a) -> ParsecT s u m a Source # | |
| MonadReader r m => MonadReader r (ParsecT s u m) # | |
| MonadState s m => MonadState s (ParsecT s' u m) # | |
| MonadTrans (ParsecT s u) # | |
| Defined in Text.Parsec.Prim | |
| MonadFail (ParsecT s u m) # | Since: parsec-3.1.12.0 | 
| MonadIO m => MonadIO (ParsecT s u m) # | |
| Alternative (ParsecT s u m) # | |
| Applicative (ParsecT s u m) # | |
| Defined in Text.Parsec.Prim Methods pure :: a -> ParsecT s u m a Source # (<*>) :: ParsecT s u m (a -> b) -> ParsecT s u m a -> ParsecT s u m b Source # liftA2 :: (a -> b -> c) -> ParsecT s u m a -> ParsecT s u m b -> ParsecT s u m c Source # (*>) :: ParsecT s u m a -> ParsecT s u m b -> ParsecT s u m b Source # (<*) :: ParsecT s u m a -> ParsecT s u m b -> ParsecT s u m a Source # | |
| Functor (ParsecT s u m) # | |
| Monad (ParsecT s u m) # | |
| MonadPlus (ParsecT s u m) # | |
| MonadCont m => MonadCont (ParsecT s u m) # | |
| (Monoid a, Semigroup (ParsecT s u m a)) => Monoid (ParsecT s u m a) # | The  Since: parsec-3.1.12 | 
| Semigroup a => Semigroup (ParsecT s u m a) # | The  (many $ char The above will parse a string like  (many $ char Since: parsec-3.1.12 | 
Arguments
| :: Stream s Identity t | |
| => (t -> String) | Token pretty-printing function. | 
| -> (t -> SourcePos) | Computes the position of a token. | 
| -> (t -> Maybe a) | Matching function for the token to parse. | 
| -> Parsec s u a | 
The parser token showTok posFromTok testTok accepts a token t
 with result x when the function testTok t returns Just xt should be returned by posFromTok t and
 the token can be shown using showTok t.
This combinator is expressed in terms of tokenPrim.
 It is used to accept user defined token streams. For example,
 suppose that we have a stream of basic tokens tupled with source
 positions. We can then define a parser that accepts single tokens as:
 mytoken x
   = token showTok posFromTok testTok
   where
     showTok (pos,t)     = show t
     posFromTok (pos,t)  = pos
     testTok (pos,t)     = if x == t then Just t else Nothingtokens :: (Stream s m t, Eq t) => ([t] -> String) -> (SourcePos -> [t] -> SourcePos) -> [t] -> ParsecT s u m [t] #
runParserT :: Stream s m t => ParsecT s u m a -> u -> SourceName -> s -> m (Either ParseError a) #
The most general way to run a parser. runParserT p state filePath
 input runs parser p on the input list of tokens input,
 obtained from source filePath with the initial user state st.
 The filePath is only used in error messages and may be the empty
 string. Returns a computation in the underlying monad m that return either a ParseError (Left) or a
 value of type a (Right).
runParser :: Stream s Identity t => Parsec s u a -> u -> SourceName -> s -> Either ParseError a #
The most general way to run a parser over the Identity monad. runParser p state filePath
 input runs parser p on the input list of tokens input,
 obtained from source filePath with the initial user state st.
 The filePath is only used in error messages and may be the empty
 string. Returns either a ParseError (Left) or a
 value of type a (Right).
 parseFromFile p fname
   = do{ input <- readFile fname
       ; return (runParser p () fname input)
       }parse :: Stream s Identity t => Parsec s () a -> SourceName -> s -> Either ParseError a #
parse p filePath input runs a parser p over Identity without user
 state. The filePath is only used in error messages and may be the
 empty string. Returns either a ParseError (Left)
 or a value of type a (Right).
 main    = case (parse numbers "" "11, 2, 43") of
            Left err  -> print err
            Right xs  -> print (sum xs)
 numbers = commaSep integerparseTest :: (Stream s Identity t, Show a) => Parsec s () a -> s -> IO () #
The expression parseTest p input applies a parser p against
 input input and prints the result to stdout. Used for testing
 parsers.
getPosition :: Monad m => ParsecT s u m SourcePos #
Returns the current source position. See also SourcePos.
modifyState :: Monad m => (u -> u) -> ParsecT s u m () #
modifyState f applies function f to the user state. Suppose
 that we want to count identifiers in a source, we could use the user
 state as:
 expr  = do{ x <- identifier
           ; modifyState (+1)
           ; return (Id x)
           }Combinators
(<|>) :: ParsecT s u m a -> ParsecT s u m a -> ParsecT s u m a infixr 1 #
This combinator implements choice. The parser p <|> q first
 applies p. If it succeeds, the value of p is returned. If p
 fails without consuming any input, parser q is tried. This
 combinator is defined equal to the mplus member of the MonadPlus
 class and the (<|>) member of Alternative.
The parser is called predictive since q is only tried when
 parser p didn't consume any input (i.e.. the look ahead is 1).
 This non-backtracking behaviour allows for both an efficient
 implementation of the parser combinators and the generation of good
 error messages.
(<?>) :: ParsecT s u m a -> String -> ParsecT s u m a infix 0 #
The parser p <?> msg behaves as parser p, but whenever the
 parser p fails without consuming any input, it replaces expect
 error messages with the expect error message msg.
This is normally used at the end of a set alternatives where we want
 to return an error message in terms of a higher level construct
 rather than returning all possible characters. For example, if the
 expr parser from the try example would fail, the error
 message is: '...: expecting expression'. Without the (<?>)
 combinator, the message would be like '...: expecting "let" or
 letter', which is less friendly.
label :: ParsecT s u m a -> String -> ParsecT s u m a #
A synonym for <?>, but as a function instead of an operator.
try :: ParsecT s u m a -> ParsecT s u m a #
The parser try p behaves like parser p, except that it
 pretends that it hasn't consumed any input when an error occurs.
This combinator is used whenever arbitrary look ahead is needed.
 Since it pretends that it hasn't consumed any input when p fails,
 the (<|>) combinator will try its second alternative even when the
 first parser failed while consuming input.
The try combinator can for example be used to distinguish
 identifiers and reserved words. Both reserved words and identifiers
 are a sequence of letters. Whenever we expect a certain reserved
 word where we can also expect an identifier we have to use the try
 combinator. Suppose we write:
 expr        = letExpr <|> identifier <?> "expression"
 letExpr     = do{ string "let"; ... }
 identifier  = many1 letterIf the user writes "lexical", the parser fails with: unexpected
 'x', expecting 't' in "let". Indeed, since the (<|>) combinator
 only tries alternatives when the first alternative hasn't consumed
 input, the identifier parser is never tried (because the prefix
 "le" of the string "let" parser is already consumed). The
 right behaviour can be obtained by adding the try combinator:
 expr        = letExpr <|> identifier <?> "expression"
 letExpr     = do{ try (string "let"); ... }
 identifier  = many1 letterunexpected :: Stream s m t => String -> ParsecT s u m a #
The parser unexpected msg always fails with an unexpected error
 message msg without consuming any input.
The parsers fail, (<?>) and unexpected are the three parsers
 used to generate error messages. Of these, only (<?>) is commonly
 used. For an example of the use of unexpected, see the definition
 of notFollowedBy.
choice :: Stream s m t => [ParsecT s u m a] -> ParsecT s u m a #
choice ps tries to apply the parsers in the list ps in order,
 until one of them succeeds. Returns the value of the succeeding
 parser.
many :: ParsecT s u m a -> ParsecT s u m [a] #
many p applies the parser p zero or more times. Returns a
    list of the returned values of p.
 identifier  = do{ c  <- letter
                 ; cs <- many (alphaNum <|> char '_')
                 ; return (c:cs)
                 }many1 :: Stream s m t => ParsecT s u m a -> ParsecT s u m [a] #
many1 p applies the parser p one or more times. Returns a
 list of the returned values of p.
word = many1 letter
skipMany :: ParsecT s u m a -> ParsecT s u m () #
skipMany p applies the parser p zero or more times, skipping
 its result.
spaces = skipMany space
skipMany1 :: Stream s m t => ParsecT s u m a -> ParsecT s u m () #
skipMany1 p applies the parser p one or more times, skipping
 its result.
count :: Stream s m t => Int -> ParsecT s u m a -> ParsecT s u m [a] #
count n p parses n occurrences of p. If n is smaller or
 equal to zero, the parser equals to return []. Returns a list of
 n values returned by p.
between :: Stream s m t => ParsecT s u m open -> ParsecT s u m close -> ParsecT s u m a -> ParsecT s u m a #
between open close p parses open, followed by p and close.
 Returns the value returned by p.
 braces  = between (symbol "{") (symbol "}")option :: Stream s m t => a -> ParsecT s u m a -> ParsecT s u m a #
option x p tries to apply parser p. If p fails without
 consuming input, it returns the value x, otherwise the value
 returned by p.
 priority  = option 0 (do{ d <- digit
                         ; return (digitToInt d)
                         })optional :: Stream s m t => ParsecT s u m a -> ParsecT s u m () #
optional p tries to apply parser p.  It will parse p or nothing.
 It only fails if p fails after consuming input. It discards the result
 of p.
sepBy :: Stream s m t => ParsecT s u m a -> ParsecT s u m sep -> ParsecT s u m [a] #
sepBy p sep parses zero or more occurrences of p, separated
 by sep. Returns a list of values returned by p.
commaSep p = p `sepBy` (symbol ",")
sepBy1 :: Stream s m t => ParsecT s u m a -> ParsecT s u m sep -> ParsecT s u m [a] #
sepBy1 p sep parses one or more occurrences of p, separated
 by sep. Returns a list of values returned by p.
endBy :: Stream s m t => ParsecT s u m a -> ParsecT s u m sep -> ParsecT s u m [a] #
endBy p sep parses zero or more occurrences of p, separated
 and ended by sep. Returns a list of values returned by p.
cStatements = cStatement `endBy` semi
endBy1 :: Stream s m t => ParsecT s u m a -> ParsecT s u m sep -> ParsecT s u m [a] #
endBy1 p sep parses one or more occurrences of p, separated
 and ended by sep. Returns a list of values returned by p.
sepEndBy :: Stream s m t => ParsecT s u m a -> ParsecT s u m sep -> ParsecT s u m [a] #
sepEndBy p sep parses zero or more occurrences of p,
 separated and optionally ended by sep, ie. haskell style
 statements. Returns a list of values returned by p.
haskellStatements = haskellStatement `sepEndBy` semi
sepEndBy1 :: Stream s m t => ParsecT s u m a -> ParsecT s u m sep -> ParsecT s u m [a] #
sepEndBy1 p sep parses one or more occurrences of p,
 separated and optionally ended by sep. Returns a list of values
 returned by p.
chainl :: Stream s m t => ParsecT s u m a -> ParsecT s u m (a -> a -> a) -> a -> ParsecT s u m a #
chainl p op x parses zero or more occurrences of p,
 separated by op. Returns a value obtained by a left associative
 application of all functions returned by op to the values returned
 by p. If there are zero occurrences of p, the value x is
 returned.
chainl1 :: Stream s m t => ParsecT s u m a -> ParsecT s u m (a -> a -> a) -> ParsecT s u m a #
chainl1 p op parses one or more occurrences of p,
 separated by op Returns a value obtained by a left associative
 application of all functions returned by op to the values returned
 by p. This parser can for example be used to eliminate left
 recursion which typically occurs in expression grammars.
 expr    = term   `chainl1` addop
 term    = factor `chainl1` mulop
 factor  = parens expr <|> integer
 mulop   =   do{ symbol "*"; return (*)   }
         <|> do{ symbol "/"; return (div) }
 addop   =   do{ symbol "+"; return (+) }
         <|> do{ symbol "-"; return (-) }chainr :: Stream s m t => ParsecT s u m a -> ParsecT s u m (a -> a -> a) -> a -> ParsecT s u m a #
chainr p op x parses zero or more occurrences of p,
 separated by op Returns a value obtained by a right associative
 application of all functions returned by op to the values returned
 by p. If there are no occurrences of p, the value x is
 returned.
chainr1 :: Stream s m t => ParsecT s u m a -> ParsecT s u m (a -> a -> a) -> ParsecT s u m a #
chainr1 p op x parses one or more occurrences of |p|,
 separated by op Returns a value obtained by a right associative
 application of all functions returned by op to the values returned
 by p.
eof :: (Stream s m t, Show t) => ParsecT s u m () #
This parser only succeeds at the end of the input. This is not a
 primitive parser but it is defined using notFollowedBy.
eof = notFollowedBy anyToken <?> "end of input"
notFollowedBy :: (Stream s m t, Show a) => ParsecT s u m a -> ParsecT s u m () #
notFollowedBy p only succeeds when parser p fails. This parser
 does not consume any input. This parser can be used to implement the
 'longest match' rule. For example, when recognizing keywords (for
 example let), we want to make sure that a keyword is not followed
 by a legal identifier character, in which case the keyword is
 actually an identifier (for example lets). We can program this
 behaviour as follows:
 keywordLet  = try (do{ string "let"
                      ; notFollowedBy alphaNum
                      })NOTE: Currently, notFollowedBy exhibits surprising behaviour
 when applied to a parser p that doesn't consume any input;
 specifically
- notFollowedBy.- notFollowedBy- lookAhead, and
- notFollowedBy- eof
See haskell/parsec#8 for more details.
manyTill :: Stream s m t => ParsecT s u m a -> ParsecT s u m end -> ParsecT s u m [a] #
manyTill p end applies parser p zero or more times until
 parser end succeeds. Returns the list of values returned by p.
 This parser can be used to scan comments:
 simpleComment   = do{ string "<!--"
                     ; manyTill anyChar (try (string "-->"))
                     }Note the overlapping parsers anyChar and string "-->", and
    therefore the use of the try combinator.
lookAhead :: Stream s m t => ParsecT s u m a -> ParsecT s u m a #
lookAhead p parses p without consuming any input.
If p fails and consumes some input, so does lookAhead. Combine with try
 if this is undesirable.
anyToken :: (Stream s m t, Show t) => ParsecT s u m t #
The parser anyToken accepts any kind of token. It is for example
 used to implement eof. Returns the accepted token.
Character Parsing
module Text.Parsec.Char
Error messages
data ParseError #
The abstract data type ParseError represents parse errors. It
 provides the source position (SourcePos) of the error
 and a list of error messages (Message). A ParseError
 can be returned by the function parse. ParseError is an
 instance of the Show and Eq classes.
Instances
| Show ParseError # | |
| Defined in Text.Parsec.Error | |
| Eq ParseError # | |
| Defined in Text.Parsec.Error | |
errorPos :: ParseError -> SourcePos #
Extracts the source position from the parse error
Position
The abstract data type SourcePos represents source positions. It
 contains the name of the source (i.e. file name), a line number and
 a column number. SourcePos is an instance of the Show, Eq and
 Ord class.
Instances
| Data SourcePos # | |
| Defined in Text.Parsec.Pos Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> SourcePos -> c SourcePos Source # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c SourcePos Source # toConstr :: SourcePos -> Constr Source # dataTypeOf :: SourcePos -> DataType Source # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c SourcePos) Source # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c SourcePos) Source # gmapT :: (forall b. Data b => b -> b) -> SourcePos -> SourcePos Source # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> SourcePos -> r Source # gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> SourcePos -> r Source # gmapQ :: (forall d. Data d => d -> u) -> SourcePos -> [u] Source # gmapQi :: Int -> (forall d. Data d => d -> u) -> SourcePos -> u Source # gmapM :: Monad m => (forall d. Data d => d -> m d) -> SourcePos -> m SourcePos Source # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> SourcePos -> m SourcePos Source # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> SourcePos -> m SourcePos Source # | |
| Show SourcePos # | |
| Eq SourcePos # | |
| Ord SourcePos # | |
type SourceName = String #
sourceName :: SourcePos -> SourceName #
Extracts the name of the source from a source position.
sourceLine :: SourcePos -> Line #
Extracts the line number from a source position.
sourceColumn :: SourcePos -> Column #
Extracts the column number from a source position.
incSourceLine :: SourcePos -> Line -> SourcePos #
Increments the line number of a source position.
incSourceColumn :: SourcePos -> Column -> SourcePos #
Increments the column number of a source position.
setSourceLine :: SourcePos -> Line -> SourcePos #
Set the line number of a source position.
setSourceColumn :: SourcePos -> Column -> SourcePos #
Set the column number of a source position.
setSourceName :: SourcePos -> SourceName -> SourcePos #
Set the name of the source.
Debugging
As a more comprehensive alternative for debugging Parsec parsers, there's also the parsec-free package.
parserTrace :: (Show t, Stream s m t) => String -> ParsecT s u m () #
parserTrace label is an impure function, implemented with Debug.Trace that
 prints to the console the remaining parser state at the time it is invoked.
 It is intended to be used for debugging parsers by inspecting their intermediate states.
*> parseTest (oneOf "aeiou" >> parserTrace "label") "atest" label: "test" ...
Since: parsec-3.1.12.0
parserTraced :: (Stream s m t, Show t) => String -> ParsecT s u m b -> ParsecT s u m b #
parserTraced label p is an impure function, implemented with Debug.Trace that
 prints to the console the remaining parser state at the time it is invoked.
 It then continues to apply parser p, and if p fails will indicate that
 the label has been backtracked.
 It is intended to be used for debugging parsers by inspecting their intermediate states.
*> parseTest (oneOf "aeiou" >> parserTraced "label" (oneOf "nope")) "atest" label: "test" label backtracked parse error at (line 1, column 2): ...
Since: parsec-3.1.12.0
Low-level operations
Arguments
| :: Stream s m t | |
| => (t -> String) | Token pretty-printing function. | 
| -> (SourcePos -> t -> s -> SourcePos) | Next position calculating function. | 
| -> (t -> Maybe a) | Matching function for the token to parse. | 
| -> ParsecT s u m a | 
The parser tokenPrim showTok nextPos testTok accepts a token t
 with result x when the function testTok t returns Just xshowTok t. The position of the next
 token should be returned when nextPos is called with the current
 source position pos, the current token t and the rest of the
 tokens toks, nextPos pos t toks.
This is the most primitive combinator for accepting tokens. For
 example, the char parser could be implemented as:
 char c
   = tokenPrim showChar nextPos testChar
   where
     showChar x        = "'" ++ x ++ "'"
     testChar x        = if x == c then Just x else Nothing
     nextPos pos x xs  = updatePosChar pos xtokenPrimEx :: Stream s m t => (t -> String) -> (SourcePos -> t -> s -> SourcePos) -> Maybe (SourcePos -> t -> s -> u -> u) -> (t -> Maybe a) -> ParsecT s u m a #
runPT :: Stream s m t => ParsecT s u m a -> u -> SourceName -> s -> m (Either ParseError a) #
unknownError :: State s u -> ParseError #
sysUnExpectError :: String -> SourcePos -> Reply s u a #
mergeErrorReply :: ParseError -> Reply s u a -> Reply s u a #
getParserState :: Monad m => ParsecT s u m (State s u) #
Returns the full parser state as a State record.
setParserState :: Monad m => State s u -> ParsecT s u m (State s u) #
setParserState st set the full parser state to st.
updateParserState :: (State s u -> State s u) -> ParsecT s u m (State s u) #
updateParserState f applies function f to the parser state.
class Monad m => Stream s m t | s -> t where #
An instance of Stream has stream type s, underlying monad m and token type t determined by the stream
Some rough guidelines for a "correct" instance of Stream:
- unfoldM uncons gives the [t] corresponding to the stream
- A Streaminstance is responsible for maintaining the "position within the stream" in the stream states. This is trivial unless you are using the monad in a non-trivial way.
Instances
| Monad m => Stream ByteString m Char # | |
| Defined in Text.Parsec.Prim Methods uncons :: ByteString -> m (Maybe (Char, ByteString)) # | |
| Monad m => Stream ByteString m Char # | |
| Defined in Text.Parsec.Prim Methods uncons :: ByteString -> m (Maybe (Char, ByteString)) # | |
| Monad m => Stream Text m Char # | |
| Monad m => Stream Text m Char # | |
| Monad m => Stream [tok] m tok # | |
| Defined in Text.Parsec.Prim | |
runParsecT :: Monad m => ParsecT s u m a -> State s u -> m (Consumed (m (Reply s u a))) #
Low-level unpacking of the ParsecT type. To run your parser, please look to runPT, runP, runParserT, runParser and other such functions.
mkPT :: Monad m => (State s u -> m (Consumed (m (Reply s u a)))) -> ParsecT s u m a #
Low-level creation of the ParsecT type. You really shouldn't have to do this.
runP :: Stream s Identity t => Parsec s u a -> u -> SourceName -> s -> Either ParseError a #
Constructors
| Ok a !(State s u) ParseError | |
| Error ParseError | 
setPosition :: Monad m => SourcePos -> ParsecT s u m () #
setPosition pos sets the current source position to pos.
setInput :: Monad m => s -> ParsecT s u m () #
setInput input continues parsing with input. The getInput and
 setInput functions can for example be used to deal with #include
 files.
Other stuff
updateState :: Monad m => (u -> u) -> ParsecT s u m () #
An alias for modifyState for backwards compatibility.
parserReturn :: a -> ParsecT s u m a #
parserBind :: ParsecT s u m a -> (a -> ParsecT s u m b) -> ParsecT s u m b #
parserFail :: String -> ParsecT s u m a #
parserZero :: ParsecT s u m a #
parserZero always fails without consuming any input. parserZero is defined
 equal to the mzero member of the MonadPlus class and to the empty member
 of the Alternative class.
parserPlus :: ParsecT s u m a -> ParsecT s u m a -> ParsecT s u m a #