megaparsec-7.0.4: Monadic parser combinators

Copyright© 2015–2018 Megaparsec contributors
LicenseFreeBSD
MaintainerMark Karpov <markkarpov92@gmail.com>
Stabilityexperimental
Portabilityportable
Safe HaskellNone
LanguageHaskell2010

Text.Megaparsec.Error

Contents

Description

Parse errors. The current version of Megaparsec supports well-typed errors instead of String-based ones. This gives a lot of flexibility in describing what exactly went wrong as well as a way to return arbitrary data in case of failure.

You probably do not want to import this module directly because Text.Megaparsec re-exports it anyway.

Synopsis

Parse error type

data ErrorItem t Source #

Data type that is used to represent “unexpected/expected” items in ParseError. The data type is parametrized over the token type t.

Since: 5.0.0

Constructors

Tokens (NonEmpty t)

Non-empty stream of tokens

Label (NonEmpty Char)

Label (cannot be empty)

EndOfInput

End of input

Instances
Functor ErrorItem Source # 
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Methods

fmap :: (a -> b) -> ErrorItem a -> ErrorItem b #

(<$) :: a -> ErrorItem b -> ErrorItem a #

Eq t => Eq (ErrorItem t) Source # 
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Methods

(==) :: ErrorItem t -> ErrorItem t -> Bool #

(/=) :: ErrorItem t -> ErrorItem t -> Bool #

Data t => Data (ErrorItem t) Source # 
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Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> ErrorItem t -> c (ErrorItem t) #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (ErrorItem t) #

toConstr :: ErrorItem t -> Constr #

dataTypeOf :: ErrorItem t -> DataType #

dataCast1 :: Typeable t0 => (forall d. Data d => c (t0 d)) -> Maybe (c (ErrorItem t)) #

dataCast2 :: Typeable t0 => (forall d e. (Data d, Data e) => c (t0 d e)) -> Maybe (c (ErrorItem t)) #

gmapT :: (forall b. Data b => b -> b) -> ErrorItem t -> ErrorItem t #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> ErrorItem t -> r #

gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> ErrorItem t -> r #

gmapQ :: (forall d. Data d => d -> u) -> ErrorItem t -> [u] #

gmapQi :: Int -> (forall d. Data d => d -> u) -> ErrorItem t -> u #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> ErrorItem t -> m (ErrorItem t) #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> ErrorItem t -> m (ErrorItem t) #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> ErrorItem t -> m (ErrorItem t) #

Ord t => Ord (ErrorItem t) Source # 
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Read t => Read (ErrorItem t) Source # 
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Show t => Show (ErrorItem t) Source # 
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Generic (ErrorItem t) Source # 
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Associated Types

type Rep (ErrorItem t) :: Type -> Type #

Methods

from :: ErrorItem t -> Rep (ErrorItem t) x #

to :: Rep (ErrorItem t) x -> ErrorItem t #

NFData t => NFData (ErrorItem t) Source # 
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rnf :: ErrorItem t -> () #

type Rep (ErrorItem t) Source # 
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type Rep (ErrorItem t) = D1 (MetaData "ErrorItem" "Text.Megaparsec.Error" "megaparsec-7.0.4-FalDmG6lqr8ILHtJkfIRcD" False) (C1 (MetaCons "Tokens" PrefixI False) (S1 (MetaSel (Nothing :: Maybe Symbol) NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 (NonEmpty t))) :+: (C1 (MetaCons "Label" PrefixI False) (S1 (MetaSel (Nothing :: Maybe Symbol) NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 (NonEmpty Char))) :+: C1 (MetaCons "EndOfInput" PrefixI False) (U1 :: Type -> Type)))

data ErrorFancy e Source #

Additional error data, extendable by user. When no custom data is necessary, the type is typically indexed by Void to “cancel” the ErrorCustom constructor.

Since: 6.0.0

Constructors

ErrorFail String

fail has been used in parser monad

ErrorIndentation Ordering Pos Pos

Incorrect indentation error: desired ordering between reference level and actual level, reference indentation level, actual indentation level

ErrorCustom e

Custom error data

Instances
Functor ErrorFancy Source # 
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Methods

fmap :: (a -> b) -> ErrorFancy a -> ErrorFancy b #

(<$) :: a -> ErrorFancy b -> ErrorFancy a #

Eq e => Eq (ErrorFancy e) Source # 
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(==) :: ErrorFancy e -> ErrorFancy e -> Bool #

(/=) :: ErrorFancy e -> ErrorFancy e -> Bool #

Data e => Data (ErrorFancy e) Source # 
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gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> ErrorFancy e -> c (ErrorFancy e) #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (ErrorFancy e) #

toConstr :: ErrorFancy e -> Constr #

dataTypeOf :: ErrorFancy e -> DataType #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (ErrorFancy e)) #

dataCast2 :: Typeable t => (forall d e0. (Data d, Data e0) => c (t d e0)) -> Maybe (c (ErrorFancy e)) #

gmapT :: (forall b. Data b => b -> b) -> ErrorFancy e -> ErrorFancy e #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> ErrorFancy e -> r #

gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> ErrorFancy e -> r #

gmapQ :: (forall d. Data d => d -> u) -> ErrorFancy e -> [u] #

gmapQi :: Int -> (forall d. Data d => d -> u) -> ErrorFancy e -> u #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> ErrorFancy e -> m (ErrorFancy e) #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> ErrorFancy e -> m (ErrorFancy e) #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> ErrorFancy e -> m (ErrorFancy e) #

Ord e => Ord (ErrorFancy e) Source # 
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Read e => Read (ErrorFancy e) Source # 
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Show e => Show (ErrorFancy e) Source # 
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Generic (ErrorFancy e) Source # 
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Associated Types

type Rep (ErrorFancy e) :: Type -> Type #

Methods

from :: ErrorFancy e -> Rep (ErrorFancy e) x #

to :: Rep (ErrorFancy e) x -> ErrorFancy e #

NFData a => NFData (ErrorFancy a) Source # 
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rnf :: ErrorFancy a -> () #

type Rep (ErrorFancy e) Source # 
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data ParseError s e Source #

ParseError s e represents a parse error parametrized over the stream type s and the custom data e.

Semigroup and Monoid instances of the data type allow to merge parse errors from different branches of parsing. When merging two ParseErrors, the longest match is preferred; if positions are the same, custom data sets and collections of message items are combined. Note that fancy errors take precedence over trivial errors in merging.

Since: 7.0.0

Constructors

TrivialError Int (Maybe (ErrorItem (Token s))) (Set (ErrorItem (Token s)))

Trivial errors, generated by Megaparsec's machinery. The data constructor includes the offset of error, unexpected token (if any), and expected tokens.

Type of the first argument was changed in the version 7.0.0.

FancyError Int (Set (ErrorFancy e))

Fancy, custom errors.

Type of the first argument was changed in the version 7.0.0.

Instances
(Eq (Token s), Eq e) => Eq (ParseError s e) Source # 
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Methods

(==) :: ParseError s e -> ParseError s e -> Bool #

(/=) :: ParseError s e -> ParseError s e -> Bool #

(Data s, Data (Token s), Ord (Token s), Data e, Ord e) => Data (ParseError s e) Source # 
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gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> ParseError s e -> c (ParseError s e) #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (ParseError s e) #

toConstr :: ParseError s e -> Constr #

dataTypeOf :: ParseError s e -> DataType #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (ParseError s e)) #

dataCast2 :: Typeable t => (forall d e0. (Data d, Data e0) => c (t d e0)) -> Maybe (c (ParseError s e)) #

gmapT :: (forall b. Data b => b -> b) -> ParseError s e -> ParseError s e #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> ParseError s e -> r #

gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> ParseError s e -> r #

gmapQ :: (forall d. Data d => d -> u) -> ParseError s e -> [u] #

gmapQi :: Int -> (forall d. Data d => d -> u) -> ParseError s e -> u #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> ParseError s e -> m (ParseError s e) #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> ParseError s e -> m (ParseError s e) #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> ParseError s e -> m (ParseError s e) #

(Show (Token s), Show e) => Show (ParseError s e) Source # 
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showsPrec :: Int -> ParseError s e -> ShowS #

show :: ParseError s e -> String #

showList :: [ParseError s e] -> ShowS #

Generic (ParseError s e) Source # 
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Associated Types

type Rep (ParseError s e) :: Type -> Type #

Methods

from :: ParseError s e -> Rep (ParseError s e) x #

to :: Rep (ParseError s e) x -> ParseError s e #

(Stream s, Ord e) => Semigroup (ParseError s e) Source # 
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(<>) :: ParseError s e -> ParseError s e -> ParseError s e #

sconcat :: NonEmpty (ParseError s e) -> ParseError s e #

stimes :: Integral b => b -> ParseError s e -> ParseError s e #

(Stream s, Ord e) => Monoid (ParseError s e) Source # 
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mempty :: ParseError s e #

mappend :: ParseError s e -> ParseError s e -> ParseError s e #

mconcat :: [ParseError s e] -> ParseError s e #

(Show s, Show (Token s), Show e, ShowErrorComponent e, Stream s, Typeable s, Typeable e) => Exception (ParseError s e) Source # 
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(NFData (Token s), NFData e) => NFData (ParseError s e) Source # 
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rnf :: ParseError s e -> () #

type Rep (ParseError s e) Source # 
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mapParseError :: Ord e' => (e -> e') -> ParseError s e -> ParseError s e' Source #

Modify the custom data component in a parse error. This could be done via fmap if not for the Ord constraint.

Since: 7.0.0

errorOffset :: ParseError s e -> Int Source #

Get offset of given ParseError.

Since: 7.0.0

data ParseErrorBundle s e Source #

A non-empty collection of ParseErrors equipped with PosState that allows to pretty-print the errors efficiently and correctly.

Since: 7.0.0

Constructors

ParseErrorBundle 

Fields

Instances
(Eq s, Eq (Token s), Eq e) => Eq (ParseErrorBundle s e) Source # 
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(Data s, Data (Token s), Ord (Token s), Data e, Ord e) => Data (ParseErrorBundle s e) Source # 
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gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> ParseErrorBundle s e -> c (ParseErrorBundle s e) #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (ParseErrorBundle s e) #

toConstr :: ParseErrorBundle s e -> Constr #

dataTypeOf :: ParseErrorBundle s e -> DataType #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (ParseErrorBundle s e)) #

dataCast2 :: Typeable t => (forall d e0. (Data d, Data e0) => c (t d e0)) -> Maybe (c (ParseErrorBundle s e)) #

gmapT :: (forall b. Data b => b -> b) -> ParseErrorBundle s e -> ParseErrorBundle s e #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> ParseErrorBundle s e -> r #

gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> ParseErrorBundle s e -> r #

gmapQ :: (forall d. Data d => d -> u) -> ParseErrorBundle s e -> [u] #

gmapQi :: Int -> (forall d. Data d => d -> u) -> ParseErrorBundle s e -> u #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> ParseErrorBundle s e -> m (ParseErrorBundle s e) #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> ParseErrorBundle s e -> m (ParseErrorBundle s e) #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> ParseErrorBundle s e -> m (ParseErrorBundle s e) #

(Show s, Show (Token s), Show e) => Show (ParseErrorBundle s e) Source # 
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Generic (ParseErrorBundle s e) Source # 
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type Rep (ParseErrorBundle s e) :: Type -> Type #

(Show s, Show (Token s), Show e, ShowErrorComponent e, Stream s, Typeable s, Typeable e) => Exception (ParseErrorBundle s e) Source # 
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(NFData s, NFData (Token s), NFData e) => NFData (ParseErrorBundle s e) Source # 
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rnf :: ParseErrorBundle s e -> () #

type Rep (ParseErrorBundle s e) Source # 
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type Rep (ParseErrorBundle s e) = D1 (MetaData "ParseErrorBundle" "Text.Megaparsec.Error" "megaparsec-7.0.4-FalDmG6lqr8ILHtJkfIRcD" False) (C1 (MetaCons "ParseErrorBundle" PrefixI True) (S1 (MetaSel (Just "bundleErrors") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 (NonEmpty (ParseError s e))) :*: S1 (MetaSel (Just "bundlePosState") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 (PosState s))))

attachSourcePos Source #

Arguments

:: (Traversable t, Stream s) 
=> (a -> Int)

How to project offset from an item (e.g. errorOffset)

-> t a

The collection of items

-> PosState s

Initial PosState

-> (t (a, SourcePos), PosState s)

The collection with SourcePoses added and the final PosState

Attach SourcePoses to items in a Traversable container given that there is a projection allowing to get an offset per item.

Items must be in ascending order with respect to their offsets.

Since: 7.0.0

Pretty-printing

class Ord a => ShowErrorComponent a where Source #

The type class defines how to print a custom component of ParseError.

Since: 5.0.0

Minimal complete definition

showErrorComponent

Methods

showErrorComponent :: a -> String Source #

Pretty-print a component of ParseError.

errorComponentLen :: a -> Int Source #

Length of the error component in characters, used for highlighting of parse errors in input string.

Since: 7.0.0

errorBundlePretty Source #

Arguments

:: (Stream s, ShowErrorComponent e) 
=> ParseErrorBundle s e

Parse error bundle to display

-> String

Textual rendition of the bundle

Pretty-print a ParseErrorBundle. All ParseErrors in the bundle will be pretty-printed in order together with the corresponding offending lines by doing a single efficient pass over the input stream. The rendered String always ends with a newline.

Since: 7.0.0

parseErrorPretty Source #

Arguments

:: (Stream s, ShowErrorComponent e) 
=> ParseError s e

Parse error to render

-> String

Result of rendering

Pretty-print a ParseError. The rendered String always ends with a newline.

Since: 5.0.0

parseErrorTextPretty Source #

Arguments

:: (Stream s, ShowErrorComponent e) 
=> ParseError s e

Parse error to render

-> String

Result of rendering

Pretty-print a textual part of a ParseError, that is, everything except for its position. The rendered String always ends with a newline.

Since: 5.1.0