Class Parser<TToken, T>

Represents a parser which consumes a stream of values of type TToken and returns a value of type T. A parser can either succeed, and return a value of type T, or fail and return a ParseError<TToken>.

Inheritance

Object
Parser<TToken, T>

Declaration

public abstract class Parser<TToken, T> : Object

Type Parameters

Name	Description
TToken	The type of the tokens in the parser's input stream.
T	The type of the value returned by the parser.

Remarks

This type is not intended to be subclassed by users of the library.

Constructors

Parser()

Declaration

protected Parser()

Methods

Assert(Func<T, Boolean>)

Creates a parser that fails if the value returned by the current parser fails to satisfy a predicate.

Declaration

public Parser<TToken, T> Assert(Func<T, bool> predicate)

Parameters

Type	Name	Description
Func<T, Boolean>	predicate	The predicate to apply to the value returned by the current parser.

Returns

Type	Description
Parser<TToken, T>	A parser that fails if the value returned by the current parser fails to satisfy `predicate`.

Assert(Func<T, Boolean>, Func<T, String>)

Creates a parser that fails if the value returned by the current parser fails to satisfy a predicate.

Declaration

public Parser<TToken, T> Assert(Func<T, bool> predicate, Func<T, string> message)

Parameters

Type	Name	Description
Func<T, Boolean>	predicate	The predicate to apply to the value returned by the current parser.
Func<T, String>	message	A function to produce a custom error message to return when the value returned by the current parser fails to satisfy the predicate.

Returns

Type	Description
Parser<TToken, T>	A parser that fails if the value returned by the current parser fails to satisfy `predicate`.

Assert(Func<T, Boolean>, String)

Creates a parser that fails if the value returned by the current parser fails to satisfy a predicate.

Declaration

public Parser<TToken, T> Assert(Func<T, bool> predicate, string message)

Parameters

Type	Name	Description
Func<T, Boolean>	predicate	The predicate to apply to the value returned by the current parser.
String	message	A custom error message to return when the value returned by the current parser fails to satisfy the predicate.

Returns

Type	Description
Parser<TToken, T>	A parser that fails if the value returned by the current parser fails to satisfy `predicate`.

AtLeastOnce()

Creates a parser that applies the current parser one or more times. The resulting parser fails if the current parser fails the first time it is applied, or if the current parser fails after consuming input.

Declaration

public Parser<TToken, IEnumerable<T>> AtLeastOnce()

Returns

Type	Description
Parser<TToken, IEnumerable<T>>	A parser that applies the current parser one or more times.

AtLeastOnceThen(Parser<TToken, U>)

Creates a parser which applies this parser one or more times until terminator succeeds. Fails if this parser fails or if terminator fails after consuming input.

Declaration

public Parser<TToken, (IEnumerable<T>, U)> AtLeastOnceThen<U>(Parser<TToken, U> terminator)

Parameters

Type	Name	Description
Parser<TToken, U>	terminator	A parser to parse a terminator.

Returns

Type	Description
Parser<TToken, (, )<IEnumerable<T>, U>>	A parser which applies this parser repeatedly until `terminator` succeeds.

Type Parameters

Name	Description
U	The return type of the `terminator` parser.

AtLeastOnceUntil(Parser<TToken, U>)

Creates a parser which applies this parser one or more times until terminator succeeds. Fails if this parser fails or if terminator fails after consuming input. The return value of terminator is ignored.

Declaration

public Parser<TToken, IEnumerable<T>> AtLeastOnceUntil<U>(Parser<TToken, U> terminator)

Parameters

Type	Name	Description
Parser<TToken, U>	terminator	A parser to parse a terminator.

Returns

Type	Description
Parser<TToken, IEnumerable<T>>	A parser which applies this parser repeatedly until `terminator` succeeds.

Type Parameters

Name	Description
U	The return type of the `terminator` parser.

Remarks

p.AtLeastOnceUntil(q) is equivalent to p.AtLeastOnceThen(q).Select(t => t.Item1).

Before(Parser<TToken, U>)

Creates a parser that applies the current parser followed by the specified parser. The resulting parser returns the result of the current parser, ignoring the result of the second parser.

Declaration

public Parser<TToken, T> Before<U>(Parser<TToken, U> parser)

Parameters

Type	Name	Description
Parser<TToken, U>	parser	The parser to apply after applying the current parser.

Returns

Type	Description
Parser<TToken, T>	A parser that applies the current parser followed by the specified parser.

Type Parameters

Name	Description
U	The type of the value returned by the second parser.

Between(Parser<TToken, U>)

Creates a parser that applies the specified parser both before and after applying the current parser. The resulting parser returns the result of the current parser, ignoring the return value of the bracketing parser.

Declaration

public Parser<TToken, T> Between<U>(Parser<TToken, U> parser)

Parameters

Type	Name	Description
Parser<TToken, U>	parser	The parser to apply before and after applying the current parser.

Returns

Type	Description
Parser<TToken, T>	A parser that applies the specified parser before and after applying the current parser.

Type Parameters

Name	Description
U	The type of the value returned by the bracketing parser.

Between<U, V>(Parser<TToken, U>, Parser<TToken, V>)

Creates a parser that applies the specified parsers before and after applying the current parser. The resulting parser returns the result of the current parser, ignoring the return values of the bracketing parsers.

Declaration

public Parser<TToken, T> Between<U, V>(Parser<TToken, U> parser1, Parser<TToken, V> parser2)

Parameters

Type	Name	Description
Parser<TToken, U>	parser1	The parser to apply before applying the current parser.
Parser<TToken, V>	parser2	The parser to apply after applying the current parser.

Returns

Type	Description
Parser<TToken, T>	A parser that applies the specified parsers before and after applying the current parser.

Type Parameters

Name	Description
U	The type of the value returned by the first parser.
V	The type of the value returned by the second parser.

Bind(Func<T, Parser<TToken, U>>)

Creates a parser that applies a transformation function to the return value of the current parser. The transformation function dynamically chooses a second parser, which is applied after applying the current parser.

Declaration

public Parser<TToken, U> Bind<U>(Func<T, Parser<TToken, U>> selector)

Parameters

Type	Name	Description
Func<T, Parser<TToken, U>>	selector	A transformation function which returns a parser to apply after applying the current parser.

Returns

Type	Description
Parser<TToken, U>	A parser which applies the current parser before applying the result of the `selector` function.

Type Parameters

Name	Description
U	The type of the return value of the second parser.

Bind<U, R>(Func<T, Parser<TToken, U>>, Func<T, U, R>)

Declaration

public Parser<TToken, R> Bind<U, R>(Func<T, Parser<TToken, U>> selector, Func<T, U, R> result)

Parameters

Type	Name	Description
Func<T, Parser<TToken, U>>	selector	A transformation function which returns a parser to apply after applying the current parser.
Func<T, U, R>	result	A function to apply to the return values of the two parsers.

Returns

Type	Description
Parser<TToken, R>	A parser which applies the current parser before applying the result of the `selector` function.

Type Parameters

Name	Description
U	The type of the return value of the second parser.
R	The type of the return value of the resulting parser.

Cast()

Cast the return value of the current parser to the specified result type.

Declaration

public Parser<TToken, U> Cast<U>()

Returns

Type	Description
Parser<TToken, U>	A parser which returns this parser's return value casted to `U`.

Type Parameters

Name	Description
U	The type to cast the return value to.

Exceptions

Type	Condition
InvalidCastException	Thrown when the return value is not an instance of `U`.

IgnoreResult()

Creates a parser which behaves like the current parser but returns Value. Equivalent to p.WithResult(Unit.Value).

Declaration

public Parser<TToken, Unit> IgnoreResult()

Returns

Type	Description
Parser<TToken, Unit>	A parser which behaves like the current parser but returns Value.

Labelled(String)

Creates a parser equivalent to the current parser, with a custom label. The label will be reported in an error message if the parser fails, instead of the default error message. Expected Label

Declaration

public Parser<TToken, T> Labelled(string label)

Parameters

Type	Name	Description
String	label	The custom label to apply to the current parser.

Returns

Type	Description
Parser<TToken, T>	A parser equivalent to the current parser, with a custom label.

Many()

Creates a parser which applies the current parser zero or more times. The resulting parser fails if the current parser fails after consuming input.

Declaration

public Parser<TToken, IEnumerable<T>> Many()

Returns

Type	Description
Parser<TToken, IEnumerable<T>>	A parser which applies the current parser zero or more times.

ManyThen(Parser<TToken, U>)

Creates a parser which applies this parser zero or more times until terminator succeeds. Fails if this parser fails or if terminator fails after consuming input.

Declaration

public Parser<TToken, (IEnumerable<T>, U)> ManyThen<U>(Parser<TToken, U> terminator)

Parameters

Type	Name	Description
Parser<TToken, U>	terminator	A parser to parse a terminator.

Returns

Type	Description
Parser<TToken, (, )<IEnumerable<T>, U>>	A parser which applies this parser repeatedly until `terminator` succeeds.

Type Parameters

Name	Description
U	The return type of `terminator`.

Map(Func<T, U>)

Creates a parser which applies the specified transformation function to the result of the current parser. This is an infix synonym for Map<TToken, T1, R>(Func<T1, R>, Parser<TToken, T1>).

Declaration

public Parser<TToken, U> Map<U>(Func<T, U> selector)

Parameters

Type	Name	Description
Func<T, U>	selector	A transformation function.

Returns

Type	Description
Parser<TToken, U>	A parser which applies `selector` to the result of the current parser.

Type Parameters

Name	Description
U	The return type of the transformation function.

MapWithInput(ReadOnlySpanFunc<TToken, T, U>)

Returns a parser which runs the current parser and applies a selector function. The selector function receives a ReadOnlySpan<T> as its first argument, and the result of the current parser as its second argument. The ReadOnlySpan<T> represents the sequence of input tokens which were consumed by the parser.

This allows you to write "pattern"-style parsers which match a sequence of tokens and return a view of the part of the input stream which they matched.

This function is an alternative name for Slice(ReadOnlySpanFunc<TToken, T, U>).

Declaration

public Parser<TToken, U> MapWithInput<U>(ReadOnlySpanFunc<TToken, T, U> selector)

Parameters

Type	Name	Description
ReadOnlySpanFunc<TToken, T, U>	selector	A selector function which computes a result of type `U`. The arguments of the selector function are a ReadOnlySpan<T> containing the sequence of input tokens which were consumed by this parser, and the result of this parser.

Returns

Type	Description
Parser<TToken, U>	A parser which runs the current parser and applies a selector function.

Type Parameters

Name	Description
U	The result type.

OfType()

Creates a parser which casts the return value of the current parser to the specified result type, or fails if the return value is not an instance of U.

Declaration

public Parser<TToken, U> OfType<U>()

Returns

Type	Description
Parser<TToken, U>	A parser which returns the current parser's return value casted to `U`, if the value is an instance of `U`.

Type Parameters

Name	Description
U	The type to cast the return value of the current parser to.

Optional()

Creates a parser which applies the current parser and returns Nothing<T>() if the current parser fails without consuming any input. The resulting parser fails if the current parser fails after consuming input.

Declaration

public Parser<TToken, Maybe<T>> Optional()

Returns

Type	Description
Parser<TToken, Maybe<T>>	A parser which applies the current parser and returns Nothing<T>() if the current parser fails without consuming any input.

Or(Parser<TToken, T>)

Creates a parser which tries to apply the current parser, applying the specified parser if the current parser fails without consuming any input. The resulting parser fails if both the current parser and the alternative parser fail, or if the current parser fails after consuming input.

Declaration

public Parser<TToken, T> Or(Parser<TToken, T> parser)

Parameters

Type	Name	Description
Parser<TToken, T>	parser	The alternative parser to apply if the current parser fails without consuming any input.

Returns

Type	Description
Parser<TToken, T>	A parser which tries to apply the current parser, and applies `parser` if the current parser fails without consuming any input.

RecoverWith(Func<ParseError<TToken>, Parser<TToken, T>>)

Creates a parser which runs the current parser, running errorHandler on failure.

Declaration

public Parser<TToken, T> RecoverWith(Func<ParseError<TToken>, Parser<TToken, T>> errorHandler)

Parameters

Type	Name	Description
Func<ParseError<TToken>, Parser<TToken, T>>	errorHandler	A function which returns a parser to apply when the current parser fails.

Returns

Type	Description
Parser<TToken, T>	A parser which runs the current parser, running `errorHandler` on failure.

Repeat(Int32)

Creates a parser which applies the current parser count times.

Declaration

public Parser<TToken, IEnumerable<T>> Repeat(int count)

Parameters

Type	Name	Description
Int32	count	The number of times to apply the current parser.

Returns

Type	Description
Parser<TToken, IEnumerable<T>>	A parser which applies the current parser `count` times.

Exceptions

Type	Condition
InvalidOperationException	`count` is less than 0.

Select(Func<T, U>)

Creates a parser which applies the specified transformation function to the result of the current parser. This is an infix synonym for Map<TToken, T1, R>(Func<T1, R>, Parser<TToken, T1>).

Declaration

public Parser<TToken, U> Select<U>(Func<T, U> selector)

Parameters

Type	Name	Description
Func<T, U>	selector	A transformation function.

Returns

Type	Description
Parser<TToken, U>	A parser which applies `selector` to the result of the current parser.

Type Parameters

Name	Description
U	The return type of the transformation function.

SelectMany<U, R>(Func<T, Parser<TToken, U>>, Func<T, U, R>)

Declaration

public Parser<TToken, R> SelectMany<U, R>(Func<T, Parser<TToken, U>> selector, Func<T, U, R> result)

Parameters

Type	Name	Description
Func<T, Parser<TToken, U>>	selector	A transformation function which returns a parser to apply after applying the current parser.
Func<T, U, R>	result	A function to apply to the return values of the two parsers.

Returns

Type	Description
Parser<TToken, R>	A parser which applies the current parser before applying the result of the `selector` function.

Type Parameters

Name	Description
U	The type of the return value of the second parser.
R	The type of the return value of the resulting parser.

Separated(Parser<TToken, U>)

Creates a parser which applies the current parser repeatedly, interleaved with a specified parser. The resulting parser ignores the return value of the separator parser.

Declaration

public Parser<TToken, IEnumerable<T>> Separated<U>(Parser<TToken, U> separator)

Parameters

Type	Name	Description
Parser<TToken, U>	separator	A parser which parses a separator to be interleaved with the current parser.

Returns

Type	Description
Parser<TToken, IEnumerable<T>>	A parser which applies the current parser repeatedly, interleaved by `separator`.

Type Parameters

Name	Description
U	The return type of the separator parser.

SeparatedAndOptionallyTerminated(Parser<TToken, U>)

Creates a parser which applies the current parser repeatedly, interleaved and optionally terminated with a specified parser. The resulting parser ignores the return value of the separator parser.

Declaration

public Parser<TToken, IEnumerable<T>> SeparatedAndOptionallyTerminated<U>(Parser<TToken, U> separator)

Parameters

Type	Name	Description
Parser<TToken, U>	separator	A parser which parses a separator to be interleaved with the current parser.

Returns

Type	Description
Parser<TToken, IEnumerable<T>>	A parser which applies the current parser repeatedly, interleaved and optionally terminated by `separator`.

Type Parameters

Name	Description
U	The return type of the separator parser.

SeparatedAndOptionallyTerminatedAtLeastOnce(Parser<TToken, U>)

Creates a parser which applies the current parser at least once, interleaved and optionally terminated with a specified parser. The resulting parser ignores the return value of the separator parser.

Declaration

public Parser<TToken, IEnumerable<T>> SeparatedAndOptionallyTerminatedAtLeastOnce<U>(Parser<TToken, U> separator)

Parameters

Type	Name	Description
Parser<TToken, U>	separator	A parser which parses a separator to be interleaved with the current parser.

Returns

Type	Description
Parser<TToken, IEnumerable<T>>	A parser which applies the current parser at least once, interleaved and optionally terminated by `separator`.

Type Parameters

Name	Description
U	The return type of the separator parser.

SeparatedAndTerminated(Parser<TToken, U>)

Creates a parser which applies the current parser repeatedly, interleaved and terminated with a specified parser. The resulting parser ignores the return value of the separator parser.

Declaration

public Parser<TToken, IEnumerable<T>> SeparatedAndTerminated<U>(Parser<TToken, U> separator)

Parameters

Type	Name	Description
Parser<TToken, U>	separator	A parser which parses a separator to be interleaved with the current parser.

Returns

Type	Description
Parser<TToken, IEnumerable<T>>	A parser which applies the current parser repeatedly, interleaved and terminated by `separator`.

Type Parameters

Name	Description
U	The return type of the separator parser.

SeparatedAndTerminatedAtLeastOnce(Parser<TToken, U>)

Creates a parser which applies the current parser at least once, interleaved and terminated with a specified parser. The resulting parser ignores the return value of the separator parser.

Declaration

public Parser<TToken, IEnumerable<T>> SeparatedAndTerminatedAtLeastOnce<U>(Parser<TToken, U> separator)

Parameters

Type	Name	Description
Parser<TToken, U>	separator	A parser which parses a separator to be interleaved with the current parser.

Returns

Type	Description
Parser<TToken, IEnumerable<T>>	A parser which applies the current parser at least once, interleaved and terminated by `separator`.

Type Parameters

Name	Description
U	The return type of the separator parser.

SeparatedAtLeastOnce(Parser<TToken, U>)

Creates a parser which applies the current parser at least once, interleaved with a specified parser. The resulting parser ignores the return value of the separator parser.

Declaration

public Parser<TToken, IEnumerable<T>> SeparatedAtLeastOnce<U>(Parser<TToken, U> separator)

Parameters

Type	Name	Description
Parser<TToken, U>	separator	A parser which parses a separator to be interleaved with the current parser.

Returns

Type	Description
Parser<TToken, IEnumerable<T>>	A parser which applies the current parser at least once, interleaved by `separator`.

Type Parameters

Name	Description
U	The return type of the separator parser.

SkipAtLeastOnce()

Creates a parser that applies the current parser one or more times, discarding the results. This is more efficient than AtLeastOnce(), if you don't need the results. The resulting parser fails if the current parser fails the first time it is applied, or if the current parser fails after consuming input.

Declaration

public Parser<TToken, Unit> SkipAtLeastOnce()

Returns

Type	Description
Parser<TToken, Unit>	A parser that applies the current parser one or more times, discarding the results.

SkipAtLeastOnceThen(Parser<TToken, U>)

Creates a parser which applies this parser one or more times until terminator succeeds, discarding the results. This is more efficient than AtLeastOnceThen(Parser<TToken, U>) if you don't need the results. Fails if this parser fails or if terminator fails after consuming input.

Declaration

public Parser<TToken, U> SkipAtLeastOnceThen<U>(Parser<TToken, U> terminator)

Parameters

Type	Name	Description
Parser<TToken, U>	terminator	A parser to parse a terminator.

Returns

Type	Description
Parser<TToken, U>	A parser which applies this parser repeatedly until `terminator` succeeds, discarding the results.

Type Parameters

Name	Description
U	The return type of the `terminator` parser.

SkipAtLeastOnceUntil(Parser<TToken, U>)

Creates a parser which applies this parser one or more times until terminator succeeds, discarding the results. This is more efficient than AtLeastOnceUntil(Parser<TToken, U>) if you don't need the results. Fails if this parser fails or if terminator fails after consuming input. The return value of terminator is ignored.

Declaration

public Parser<TToken, Unit> SkipAtLeastOnceUntil<U>(Parser<TToken, U> terminator)

Parameters

Type	Name	Description
Parser<TToken, U>	terminator	A parser to parse a terminator.

Returns

Type	Description
Parser<TToken, Unit>	A parser which applies this parser repeatedly until `terminator` succeeds, discarding the results.

Type Parameters

Name	Description
U	The return type of the `terminator` parser.

Remarks

p.SkipAtLeastOnceUntil(q) is equivalent to p.SkipAtLeastOnceThen(q).ThenReturn(Unit.Value).

SkipMany()

Creates a parser which applies the current parser zero or more times, discarding the results. This is more efficient than Many(), if you don't need the results. The resulting parser fails if the current parser fails after consuming input.

Declaration

public Parser<TToken, Unit> SkipMany()

Returns

Type	Description
Parser<TToken, Unit>	A parser which applies the current parser zero or more times.

SkipManyThen(Parser<TToken, U>)

Creates a parser which applies this parser zero or more times until terminator succeeds, discarding the results. This is more efficient than ManyThen(Parser<TToken, U>) if you don't need the results. Fails if this parser fails or if terminator fails after consuming input.

Declaration

public Parser<TToken, U> SkipManyThen<U>(Parser<TToken, U> terminator)

Parameters

Type	Name	Description
Parser<TToken, U>	terminator	A parser to parse a terminator.

Returns

Type	Description
Parser<TToken, U>	A parser which applies this parser repeatedly until `terminator` succeeds, discarding the results.

Type Parameters

Name	Description
U	The return type of `terminator`.

SkipUntil(Parser<TToken, U>)

Creates a parser which applies this parser zero or more times until terminator succeeds, discarding the results. This is more efficient than Until(Parser<TToken, U>) if you don't need the results. Fails if this parser fails or if terminator fails after consuming input. The return value of terminator is ignored.

Declaration

public Parser<TToken, Unit> SkipUntil<U>(Parser<TToken, U> terminator)

Parameters

Type	Name	Description
Parser<TToken, U>	terminator	A parser to parse a terminator.

Returns

Type	Description
Parser<TToken, Unit>	A parser which applies this parser repeatedly until `terminator` succeeds, discarding the results.

Type Parameters

Name	Description
U	The return type of `terminator`.

Remarks

p.SkipUntil(q) is equivalent to p.SkipManyThen(q).ThenReturn(Unit.Value).

Slice(ReadOnlySpanFunc<TToken, T, U>)

This allows you to write "pattern"-style parsers which match a sequence of tokens and return a view of the part of the input stream which they matched.

This function is an alternative name for MapWithInput(ReadOnlySpanFunc<TToken, T, U>).

Declaration

public Parser<TToken, U> Slice<U>(ReadOnlySpanFunc<TToken, T, U> selector)

Parameters

Type	Name	Description
ReadOnlySpanFunc<TToken, T, U>	selector	A selector function which computes a result of type `U`. The arguments of the selector function are a ReadOnlySpan<T> containing the sequence of input tokens which were consumed by this parser, and the result of this parser.

Returns

Type	Description
Parser<TToken, U>	A parser which runs the current parser and applies a selector function.

Type Parameters

Name	Description
U	The result type.

Then(Parser<TToken, U>)

Creates a parser which applies the current parser followed by a specified parser. The resulting parser returns the result of the second parser, ignoring the result of the current parser.

Declaration

public Parser<TToken, U> Then<U>(Parser<TToken, U> parser)

Parameters

Type	Name	Description
Parser<TToken, U>	parser	A parser to apply after applying the current parser.

Returns

Type	Description
Parser<TToken, U>	A parser which applies the current parser followed by `parser`.

Type Parameters

Name	Description
U	The return type of the second parser.

Then(Func<T, Parser<TToken, U>>)

Declaration

public Parser<TToken, U> Then<U>(Func<T, Parser<TToken, U>> selector)

Parameters

Type	Name	Description
Func<T, Parser<TToken, U>>	selector	A transformation function which returns a parser to apply after applying the current parser.

Returns

Type	Description
Parser<TToken, U>	A parser which applies the current parser before applying the result of the `selector` function.

Type Parameters

Name	Description
U	The type of the return value of the second parser.

Remarks

This function is a synonym for Bind(Func<T, Parser<TToken, U>>).

Then<U, R>(Parser<TToken, U>, Func<T, U, R>)

Creates a parser which applies the current parser followed by a specified parser, applying a function to the two results.

Declaration

public Parser<TToken, R> Then<U, R>(Parser<TToken, U> parser, Func<T, U, R> result)

Parameters

Type	Name	Description
Parser<TToken, U>	parser	A parser to apply after applying the current parser.
Func<T, U, R>	result	A function to apply to the two parsed values.

Returns

Type	Description
Parser<TToken, R>	A parser which applies the current parser followed by `parser`.

Type Parameters

Name	Description
U	The return type of the second parser.
R	The return type of the composed parser.

Remarks

This is a synonym for Map<TToken, T1, T2, R>(Func<T1, T2, R>, Parser<TToken, T1>, Parser<TToken, T2>) with the arguments rearranged.

Then<U, R>(Func<T, Parser<TToken, U>>, Func<T, U, R>)

Declaration

public Parser<TToken, R> Then<U, R>(Func<T, Parser<TToken, U>> selector, Func<T, U, R> result)

Parameters

Type	Name	Description
Func<T, Parser<TToken, U>>	selector	A transformation function which returns a parser to apply after applying the current parser.
Func<T, U, R>	result	A function to apply to the return values of the two parsers.

Returns

Type	Description
Parser<TToken, R>	A parser which applies the current parser before applying the result of the `selector` function.

Type Parameters

Name	Description
U	The type of the return value of the second parser.
R	The type of the return value of the resulting parser.

Remarks

This function is a synonym for Bind<U, R>(Func<T, Parser<TToken, U>>, Func<T, U, R>).

ThenReturn(U)

Creates a parser which behaves like the current parser but returns result after a successful parse. This is a synonym for WithResult(U).

Declaration

public Parser<TToken, U> ThenReturn<U>(U result)

Parameters

Type	Name	Description
U	result	The result.

Returns

Type	Description
Parser<TToken, U>	A parser which behaves like the current parser but returns `result`.

Type Parameters

Name	Description
U	The type of the result.

Examples

Equivalent to using Select(Func<T, U>) with a function that returns a fixed value, or Then(Parser<TToken, U>) with Return<T>(T).

p.ThenReturn(x) == p.Select(_ => x) == p.Then(Return(x));

Trace(Func<T, String>)

For debugging use.

Creates a new parser which runs the current parser and prints the given message to the console.

Declaration

public Parser<TToken, T> Trace(Func<T, string> message)

Parameters

Type	Name	Description
Func<T, String>	message	A message to write to the console.

Returns

Type	Description
Parser<TToken, T>	A parser which runs the current parser and prints the given message to the console.

Trace(String)

For debugging use.

Creates a new parser which runs the current parser and prints the given message to the console.

Declaration

public Parser<TToken, T> Trace(string message)

Parameters

Type	Name	Description
String	message	A message to write to the console.

Returns

Type	Description
Parser<TToken, T>	A parser which runs the current parser and prints the given message to the console.

TraceResult()

For debugging use.

Creates a new parser which runs the current parser and prints the result to the console.

Declaration

public Parser<TToken, T> TraceResult()

Returns

Type	Description
Parser<TToken, T>	A parser which runs the current parser and prints the result to the console.

TryParse(ref ParseState<TToken>, ref PooledList<Expected<TToken>>, out T)

Override this method to implement a custom parser. Use this if you can't do what you need using the base parser combinators.

If your parser fails it should return false and call SetError(Maybe<TToken>, Boolean, Int32, String).

WARNING: This API is unstable and subject to change in future versions of the library.

Declaration

public abstract bool TryParse(ref ParseState<TToken> state, ref PooledList<Expected<TToken>> expecteds, out T result)

Parameters

Type	Name	Description
ParseState<TToken>	state	The parser's state.
PooledList<Expected<TToken>>	expecteds	A list to which the parser can add its expected tokens when it fails.
T	result	The result.

Returns

Type	Description
Boolean	True if the parser succeeded, false if it failed.

Until(Parser<TToken, U>)

Creates a parser which applies this parser zero or more times until terminator succeeds. Fails if this parser fails or if terminator fails after consuming input. The return value of terminator is ignored.

Declaration

public Parser<TToken, IEnumerable<T>> Until<U>(Parser<TToken, U> terminator)

Parameters

Type	Name	Description
Parser<TToken, U>	terminator	A parser to parse a terminator.

Returns

Type	Description
Parser<TToken, IEnumerable<T>>	A parser which applies this parser repeatedly until `terminator` succeeds.

Type Parameters

Name	Description
U	The return type of `terminator`.

Remarks

p.Until(q) is equivalent to p.ManyThen(q).Select(t => t.Item1).

Where(Func<T, Boolean>)

Creates a parser that fails if the value returned by the current parser fails to satisfy a predicate.

Declaration

public Parser<TToken, T> Where(Func<T, bool> predicate)

Parameters

Type	Name	Description
Func<T, Boolean>	predicate	The predicate to apply to the value returned by the current parser.

Returns

Type	Description
Parser<TToken, T>	A parser that fails if the value returned by the current parser fails to satisfy `predicate`.

Remarks

This function is a synonym of Assert(Func<T, Boolean>).

WithResult(U)

Creates a parser which behaves like the current parser but returns result after a successful parse. This is a synonym for ThenReturn(U).

Declaration

public Parser<TToken, U> WithResult<U>(U result)

Parameters

Type	Name	Description
U	result	The result.

Returns

Type	Description
Parser<TToken, U>	A parser which behaves like the current parser but returns `result`.

Type Parameters

Name	Description
U	The type of the result.

Examples

Equivalent to using Select(Func<T, U>) with a function that returns a fixed value, or Then(Parser<TToken, U>) with Return<T>(T).

p.WithResult(x) == p.Select(_ => x) == p.Then(Return(x));

Extension Methods

ParserExtensions.Parse<TToken, T>(Parser<TToken, T>, IList<TToken>, IConfiguration<TToken>)

ParserExtensions.ParseReadOnlyList<TToken, T>(Parser<TToken, T>, IReadOnlyList<TToken>, IConfiguration<TToken>)

ParserExtensions.Parse<TToken, T>(Parser<TToken, T>, IEnumerable<TToken>, IConfiguration<TToken>)

ParserExtensions.Parse<TToken, T>(Parser<TToken, T>, IEnumerator<TToken>, IConfiguration<TToken>)

ParserExtensions.Parse<TToken, T>(Parser<TToken, T>, TToken[], IConfiguration<TToken>)

ParserExtensions.Parse<TToken, T>(Parser<TToken, T>, ReadOnlySpan<TToken>, IConfiguration<TToken>)

ParserExtensions.ParseOrThrow<TToken, T>(Parser<TToken, T>, IList<TToken>, IConfiguration<TToken>)

ParserExtensions.ParseReadOnlyListOrThrow<TToken, T>(Parser<TToken, T>, IReadOnlyList<TToken>, IConfiguration<TToken>)

ParserExtensions.ParseOrThrow<TToken, T>(Parser<TToken, T>, IEnumerable<TToken>, IConfiguration<TToken>)

ParserExtensions.ParseOrThrow<TToken, T>(Parser<TToken, T>, IEnumerator<TToken>, IConfiguration<TToken>)

ParserExtensions.ParseOrThrow<TToken, T>(Parser<TToken, T>, TToken[], IConfiguration<TToken>)

ParserExtensions.ParseOrThrow<TToken, T>(Parser<TToken, T>, ReadOnlySpan<TToken>, IConfiguration<TToken>)