Copyright	© 2015–present Megaparsec contributors
License	FreeBSD
Maintainer	Mark Karpov <markkarpov92@gmail.com>
Stability	experimental
Portability	portable
Safe Haskell	Safe
Language	Haskell2010

Text.Megaparsec.Error

Contents

Parse error type
Pretty-printing

Description

Parse errors. The current version of Megaparsec supports 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

data ErrorItem t
- = Tokens (NonEmpty t)
- | Label (NonEmpty Char)
- | EndOfInput
data ErrorFancy e
- = ErrorFail String
- | ErrorIndentation Ordering Pos Pos
- | ErrorCustom e
data ParseError s e
- = TrivialError Int (Maybe (ErrorItem (Token s))) (Set (ErrorItem (Token s)))
- | FancyError Int (Set (ErrorFancy e))
mapParseError :: Ord e' => (e -> e') -> ParseError s e -> ParseError s e'
errorOffset :: ParseError s e -> Int
setErrorOffset :: Int -> ParseError s e -> ParseError s e
data ParseErrorBundle s e = ParseErrorBundle {
- bundleErrors :: NonEmpty (ParseError s e)
- bundlePosState :: PosState s
}
attachSourcePos :: (Traversable t, TraversableStream s) => (a -> Int) -> t a -> PosState s -> (t (a, SourcePos), PosState s)
class Ord a => ShowErrorComponent a where
- showErrorComponent :: a -> String
- errorComponentLen :: a -> Int
errorBundlePretty :: forall s e. (VisualStream s, TraversableStream s, ShowErrorComponent e) => ParseErrorBundle s e -> String
errorBundlePrettyForGhcPreProcessors :: forall s e. (VisualStream s, TraversableStream s, ShowErrorComponent e) => ParseErrorBundle s e -> String
errorBundlePrettyWith :: forall s e. (VisualStream s, TraversableStream s) => (Maybe String -> SourcePos -> ParseError s e -> String) -> ParseErrorBundle s e -> String
parseErrorPretty :: (VisualStream s, ShowErrorComponent e) => ParseError s e -> String
parseErrorTextPretty :: forall s e. (VisualStream s, ShowErrorComponent e) => ParseError s e -> String
showErrorItem :: VisualStream s => Proxy s -> ErrorItem (Token s) -> String

Parse error type

data ErrorItem t Source #

A data type that is used to represent “unexpected/expected” items in ParseError . It 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

Instances details

Functor ErrorItem Source #

Instance details

Defined in Text.Megaparsec.Error

Methods

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

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

Data t => Data (ErrorItem t) Source #

Instance details

Defined in Text.Megaparsec.Error

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 :: forall r r'. (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) #

Generic (ErrorItem t) Source #

Instance details

Defined in Text.Megaparsec.Error

Associated Types

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

Methods

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

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

Read t => Read (ErrorItem t) Source #

Instance details

Defined in Text.Megaparsec.Error

Methods

readsPrec :: Int -> ReadS (ErrorItem t) #

readList :: ReadS [ErrorItem t] #

readPrec :: ReadPrec (ErrorItem t) #

readListPrec :: ReadPrec [ErrorItem t] #

Show t => Show (ErrorItem t) Source #

Instance details

Defined in Text.Megaparsec.Error

Methods

showsPrec :: Int -> ErrorItem t -> ShowS #

show :: ErrorItem t -> String #

showList :: [ErrorItem t] -> ShowS #

NFData t => NFData (ErrorItem t) Source #

Instance details

Defined in Text.Megaparsec.Error

Methods

rnf :: ErrorItem t -> () #

Eq t => Eq (ErrorItem t) Source #

Instance details

Defined in Text.Megaparsec.Error

Methods

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

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

Ord t => Ord (ErrorItem t) Source #

Instance details

Defined in Text.Megaparsec.Error

Methods

compare :: ErrorItem t -> ErrorItem t -> Ordering #

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

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

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

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

max :: ErrorItem t -> ErrorItem t -> ErrorItem t #

min :: ErrorItem t -> ErrorItem t -> ErrorItem t #

type Rep (ErrorItem t) Source #

Instance details

Defined in Text.Megaparsec.Error

type Rep (ErrorItem t) = D1 ('MetaData "ErrorItem" "Text.Megaparsec.Error" "megaparsec-9.7.0-cVr8MhPfyWAvJ9ifq02qF" '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

Instances details

Functor ErrorFancy Source #

Instance details

Defined in Text.Megaparsec.Error

Methods

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

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

Data e => Data (ErrorFancy e) Source #

Instance details

Defined in Text.Megaparsec.Error

Methods

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 :: forall r r'. (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) #

Generic (ErrorFancy e) Source #

Instance details

Defined in Text.Megaparsec.Error

Associated Types

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

Methods

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

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

Read e => Read (ErrorFancy e) Source #

Instance details

Defined in Text.Megaparsec.Error

Methods

readsPrec :: Int -> ReadS (ErrorFancy e) #

readList :: ReadS [ErrorFancy e] #

readPrec :: ReadPrec (ErrorFancy e) #

readListPrec :: ReadPrec [ErrorFancy e] #

Show e => Show (ErrorFancy e) Source #

Instance details

Defined in Text.Megaparsec.Error

Methods

showsPrec :: Int -> ErrorFancy e -> ShowS #

show :: ErrorFancy e -> String #

showList :: [ErrorFancy e] -> ShowS #

NFData a => NFData (ErrorFancy a) Source #

Instance details

Defined in Text.Megaparsec.Error

Methods

rnf :: ErrorFancy a -> () #

Eq e => Eq (ErrorFancy e) Source #

Instance details

Defined in Text.Megaparsec.Error

Methods

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

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

Ord e => Ord (ErrorFancy e) Source #

Instance details

Defined in Text.Megaparsec.Error

Methods

compare :: ErrorFancy e -> ErrorFancy e -> Ordering #

(<) :: ErrorFancy e -> ErrorFancy e -> Bool #

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

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

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

max :: ErrorFancy e -> ErrorFancy e -> ErrorFancy e #

min :: ErrorFancy e -> ErrorFancy e -> ErrorFancy e #

type Rep (ErrorFancy e) Source #

Instance details

Defined in Text.Megaparsec.Error

type Rep (ErrorFancy e) = D1 ('MetaData "ErrorFancy" "Text.Megaparsec.Error" "megaparsec-9.7.0-cVr8MhPfyWAvJ9ifq02qF" 'False) (C1 ('MetaCons "ErrorFail" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 String)) :+: (C1 ('MetaCons "ErrorIndentation" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Ordering) :*: (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Pos) :*: S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Pos))) :+: C1 ('MetaCons "ErrorCustom" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 e))))

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 us to merge parse errors from different branches of parsing. When merging two ParseError s, 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 the 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

Instances details

(Data s, Data (Token s), Ord (Token s), Data e, Ord e) => Data (ParseError s e) Source #

Instance details

Defined in Text.Megaparsec.Error

Methods

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 :: forall r r'. (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) #

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

Instance details

Defined in Text.Megaparsec.Error

Methods

mempty :: ParseError s e #

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

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

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

Instance details

Defined in Text.Megaparsec.Error

Methods

(<>) :: 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 #

(Show s, Show (Token s), Show e, ShowErrorComponent e, VisualStream s, Typeable s, Typeable e) => Exception (ParseError s e) Source #

Instance details

Defined in Text.Megaparsec.Error

Methods

toException :: ParseError s e -> SomeException #

fromException :: SomeException -> Maybe (ParseError s e) #

displayException :: ParseError s e -> String #

Generic (ParseError s e) Source #

Instance details

Defined in Text.Megaparsec.Error

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 #

(Show (Token s), Show e) => Show (ParseError s e) Source #

Instance details

Defined in Text.Megaparsec.Error

Methods

showsPrec :: Int -> ParseError s e -> ShowS #

show :: ParseError s e -> String #

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

(NFData (Token s), NFData e) => NFData (ParseError s e) Source #

Instance details

Defined in Text.Megaparsec.Error

Methods

rnf :: ParseError s e -> () #

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

Instance details

Defined in Text.Megaparsec.Error

Methods

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

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

type Rep (ParseError s e) Source #

Instance details

Defined in Text.Megaparsec.Error

type Rep (ParseError s e) = D1 ('MetaData "ParseError" "Text.Megaparsec.Error" "megaparsec-9.7.0-cVr8MhPfyWAvJ9ifq02qF" 'False) (C1 ('MetaCons "TrivialError" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Int) :*: (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 (Maybe (ErrorItem (Token s)))) :*: S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 (Set (ErrorItem (Token s)))))) :+: C1 ('MetaCons "FancyError" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Int) :*: S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 (Set (ErrorFancy e)))))

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 the offset of a ParseError .

Since: 7.0.0

setErrorOffset :: Int -> ParseError s e -> ParseError s e Source #

Set the offset of a ParseError .

Since: 8.0.0

data ParseErrorBundle s e Source #

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

Since: 7.0.0

Constructors

ParseErrorBundle

Fields

bundleErrors :: NonEmpty (ParseError s e)
A collection of ParseError s that is sorted by parse error offsets
bundlePosState :: PosState s
The state that is used for line/column calculation

Instances

Instances details

(Data s, Data (Token s), Ord (Token s), Data e, Ord e) => Data (ParseErrorBundle s e) Source #

Instance details

Defined in Text.Megaparsec.Error

Methods

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 :: forall r r'. (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, ShowErrorComponent e, VisualStream s, TraversableStream s, Typeable s, Typeable e) => Exception (ParseErrorBundle s e) Source #

Instance details

Defined in Text.Megaparsec.Error

Methods

toException :: ParseErrorBundle s e -> SomeException #

fromException :: SomeException -> Maybe (ParseErrorBundle s e) #

displayException :: ParseErrorBundle s e -> String #

Generic (ParseErrorBundle s e) Source #

Instance details

Defined in Text.Megaparsec.Error

Associated Types

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

Methods

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

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

(Show s, Show (Token s), Show e) => Show (ParseErrorBundle s e) Source #

Instance details

Defined in Text.Megaparsec.Error

Methods

showsPrec :: Int -> ParseErrorBundle s e -> ShowS #

show :: ParseErrorBundle s e -> String #

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

(NFData s, NFData (Token s), NFData e) => NFData (ParseErrorBundle s e) Source #

Instance details

Defined in Text.Megaparsec.Error

Methods

rnf :: ParseErrorBundle s e -> () #

(Eq s, Eq (Token s), Eq e) => Eq (ParseErrorBundle s e) Source #

Instance details

Defined in Text.Megaparsec.Error

Methods

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

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

type Rep (ParseErrorBundle s e) Source #

Instance details

Defined in Text.Megaparsec.Error

type Rep (ParseErrorBundle s e) = D1 ('MetaData "ParseErrorBundle" "Text.Megaparsec.Error" "megaparsec-9.7.0-cVr8MhPfyWAvJ9ifq02qF" '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, TraversableStream 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 SourcePos es added and the final PosState

Attach SourcePos es to items in a Traversable container given that there is a projection allowing us 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

Instances

Instances details

ShowErrorComponent Void Source #

Instance details

Defined in Text.Megaparsec.Error

Methods

showErrorComponent :: Void -> String Source #

errorComponentLen :: Void -> Int Source #

errorBundlePretty Source #

Arguments

:: forall s e. (VisualStream s, TraversableStream s, ShowErrorComponent e)

=> ParseErrorBundle s e

Parse error bundle to display

-> String

Textual rendition of the bundle

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

Since: 7.0.0

errorBundlePrettyForGhcPreProcessors Source #

Arguments

:: forall s e. (VisualStream s, TraversableStream s, ShowErrorComponent e)

=> ParseErrorBundle s e

Parse error bundle to display

-> String

Textual rendition of the bundle

Pretty-print a ParseErrorBundle . All ParseError s in the bundle will be pretty-printed in order by doing a single pass over the input stream.

The rendered format is suitable for custom GHC pre-processors (as can be specified with -F -pgmF).

Since: 9.7.0

errorBundlePrettyWith Source #

Arguments

:: forall s e. (VisualStream s, TraversableStream s)

=> (Maybe String -> SourcePos -> ParseError s e -> String)

Format function for a single ParseError

-> ParseErrorBundle s e

Parse error bundle to display

-> String

Textual rendition of the bundle

Pretty-print a ParseErrorBundle . All ParseError s in the bundle will be pretty-printed in order, by applying a provided format function, with a single pass over the input stream.

Since: 9.7.0

parseErrorPretty Source #

Arguments

:: (VisualStream 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