Modulehspec-megaparsec-2.2.1GHC2021

Test.Hspec.Megaparsec

Utility functions for testing Megaparsec parsers with Hspec.

2 types
21 values

Packagehspec-megaparsec-2.2.1
Exports23
LanguageGHC2021
LicenceBSD-3-Clause
SourceMegaparsec.hs

Basic expectations

4 declarations

valueshouldParse

:: (HasCallStack, ShowErrorComponent e, Stream s, VisualStream s, TraversableStream s, Show a, Eq a)
=> Either (ParseErrorBundle s e) a
Result of parsing as returned by function like parse
-> a
Desired result
-> Expectation

Create an expectation by saying what the result should be.

parse letterChar "" "x" `shouldParse` 'x'

valueparseSatisfies

:: (HasCallStack, ShowErrorComponent e, Stream s, VisualStream s, TraversableStream s, Show a, Eq a)
=> Either (ParseErrorBundle s e) a
Result of parsing as returned by function like parse
-> (a -> Bool)
Predicate
-> Expectation

Create an expectation by saying that the parser should successfully parse a value and that the value should satisfy some predicate.

parse (many punctuationChar) "" "?!!" `parseSatisfies` ((== 3) . length)

valueshouldSucceedOn

:: (HasCallStack, ShowErrorComponent e, Stream s, VisualStream s, TraversableStream s, Show a)
=> (s -> Either (ParseErrorBundle s e) a)
Parser that takes stream and produces result or error message
-> s
Input that the parser should succeed on
-> Expectation

Check that a parser succeeds on a given input.

parse (char 'x') "" `shouldSucceedOn` "x"

valueshouldFailOn

:: (HasCallStack, Show a)
=> (s -> Either (ParseErrorBundle s e) a)
Parser that takes stream and produces result or error message
-> s
Input that the parser should fail on
-> Expectation

Check that a parser fails on a given input.

parse (char 'x') "" `shouldFailOn` "a"

Testing of error messages

2 declarations

valueshouldFailWith

:: (HasCallStack, ShowErrorComponent e, Stream s, VisualStream s, TraversableStream s, Show a, Eq e)
=> Either (ParseErrorBundle s e) a
The result of parsing
-> ParseError s e
Expected parse errors
-> Expectation

Create an expectation that parser should fail producing certain ParseError. Use the err function from this module to construct a ParseError to compare with.

parse (char 'x') "" "b" `shouldFailWith` err posI (utok 'b' <> etok 'x')

valueshouldFailWithM

:: (HasCallStack, ShowErrorComponent e, Stream s, VisualStream s, TraversableStream s, Show a, Eq e)
=> Either (ParseErrorBundle s e) a
The result of parsing
-> [ParseError s e]
Expected parse errors, the argument is a normal linked list (as opposed to the more correct NonEmpty list) as a syntactical convenience for the user, passing empty list here will result in an error
-> Expectation

Similar to shouldFailWith, but allows us to check parsers that can report more than one parse error at a time.

Incremental parsing

4 declarations

valuefailsLeaving

:: (HasCallStack, Show a, Eq s, Show s)
=> (State s e, Either (ParseErrorBundle s e) a)
Parser that takes stream and produces result along with actual state information
-> s
Part of input that should be left unconsumed
-> Expectation

Check that a parser fails and leaves a certain part of input unconsumed. Use it with functions like runParser' and runParserT' that support incremental parsing.

runParser' (many (char 'x') <* eof) (initialState "xxa")
  `failsLeaving` "a"

Re-exports

13 declarations

valueerr

:: Int
ParseError offset
-> ET s
Error components
-> ParseError s e
Resulting ParseError

Assemble a ParseError from the offset and the ET t value. ET t is a monoid and can be assembled by combining primitives provided by this module, see below.

newtypenewtype EF e

Auxiliary type for construction of fancy parse errors.

Instances7Eq, Data, Ord, Generic, Semigroup, Monoid, …

Eq e => Eq (EF e)Defined in megaparsec-9.7.0 · Text.Megaparsec.Error.Builder
(Data e, Ord e) => Data (EF e)Defined in megaparsec-9.7.0 · Text.Megaparsec.Error.Builder
Ord e => Ord (EF e)Defined in megaparsec-9.7.0 · Text.Megaparsec.Error.Builder
Generic (EF e)Defined in megaparsec-9.7.0 · Text.Megaparsec.Error.Builder
Ord e => Semigroup (EF e)Defined in megaparsec-9.7.0 · Text.Megaparsec.Error.Builder
Ord e => Monoid (EF e)Defined in megaparsec-9.7.0 · Text.Megaparsec.Error.Builder
type Rep (EF e) = D1 ('MetaData "EF" "Text.Megaparsec.Error.Builder" "megaparsec-9.7.0-Jiz5oe6zAALBOFyVFbTGRU" 'True) (C1 ('MetaCons "EF" 'PrefixI 'False) (S1 ('MetaSel 'Nothing 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 (Set (ErrorFancy e)))))Defined in megaparsec-9.7.0 · Text.Megaparsec.Error.Builder

datadata ET s

Auxiliary type for construction of trivial parse errors.

Instances7Eq, Data, Ord, Generic, Semigroup, Monoid, …

Eq (Token s) => Eq (ET s)Defined in megaparsec-9.7.0 · Text.Megaparsec.Error.Builder
(Data s, Data (Token s), Ord (Token s)) => Data (ET s)Defined in megaparsec-9.7.0 · Text.Megaparsec.Error.Builder
Ord (Token s) => Ord (ET s)Defined in megaparsec-9.7.0 · Text.Megaparsec.Error.Builder
Generic (ET s)Defined in megaparsec-9.7.0 · Text.Megaparsec.Error.Builder
Stream s => Semigroup (ET s)Defined in megaparsec-9.7.0 · Text.Megaparsec.Error.Builder
Stream s => Monoid (ET s)Defined in megaparsec-9.7.0 · Text.Megaparsec.Error.Builder
type Rep (ET s) = D1 ('MetaData "ET" "Text.Megaparsec.Error.Builder" "megaparsec-9.7.0-Jiz5oe6zAALBOFyVFbTGRU" 'False) (C1 ('MetaCons "ET" 'PrefixI 'False) (S1 ('MetaSel 'Nothing 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 (Maybe (ErrorItem (Token s)))) :*: S1 ('MetaSel 'Nothing 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 (Set (ErrorItem (Token s))))))Defined in megaparsec-9.7.0 · Text.Megaparsec.Error.Builder

valueeeof :: ET s

Construct an “expected end of input” error component.

valueelabel :: String -> ET s

Construct an “expected label” error component. Do not use with empty strings.

valueerrFancy

:: Int
ParseError offset
-> EF e
Error components
-> ParseError s e
Resulting ParseError

Like err, but constructs a “fancy” ParseError.

valueetok :: Token s -> ET s

Construct an “expected token” error component.

valueetoks :: Stream s => Tokens s -> ET s

Construct an “expected tokens” error component. Empty chunk produces EndOfInput.

valuefancy :: ErrorFancy e -> EF e

Construct a custom error component.

valueueof :: ET s

Construct an “unexpected end of input” error component.

valueulabel :: String -> ET s

Construct an “unexpected label” error component. Do not use with empty strings (for empty strings it's bottom).

valueutok :: Token s -> ET s

Construct an “unexpected token” error component.

valueutoks :: Stream s => Tokens s -> ET s

Construct an “unexpected tokens” error component. Empty chunk produces EndOfInput.