Class ParseState<TToken>
Represents the state of a parsing process. Includes functionality managing and buffering the input stream, reporting errors, and computing source positions.
For efficiency, this object is implemented as a mutable struct and is intended to be passed by reference.
WARNING: This API is unstable and subject to change in future versions of the library.
Inheritance
- Object
- ParseState<TToken>
Declaration
public sealed class ParseState<TToken> : ValueTypeType Parameters
| Name | Description |
|---|---|
TToken |
The type of tokens consumed by the parser. |
Properties
Configuration
Gets the parser configuration.
Declaration
public IConfiguration<TToken> Configuration { get; }Property Value
| Type | Description |
|---|---|
IConfiguration<TToken> |
Current
Returns the current token.
Declaration
public TToken Current { get; }Property Value
| Type | Description |
|---|---|
TToken |
HasCurrent
Returns true if the parser has not reached the end of the input.
Declaration
public bool HasCurrent { get; }Property Value
| Type | Description |
|---|---|
Location
Returns the total number of tokens which have been consumed. In other words, the current absolute offset of the input stream.
Declaration
public int Location { get; }Property Value
| Type | Description |
|---|---|
Methods
Advance(Int32)
Advance the input stream by count tokens.
Declaration
public void Advance(int count = 1)Parameters
| Type | Name | Description |
|---|---|---|
count |
The number of tokens to advance. |
Bookmark()
Start buffering the input.
Declaration
public int Bookmark()Returns
| Type | Description |
|---|---|
The location of the bookmark. |
DiscardBookmark(Int32)
Stop buffering the input.
Declaration
public void DiscardBookmark(int bookmark)Parameters
| Type | Name | Description |
|---|---|---|
bookmark |
The location of the bookmark. |
LookAhead(Int32)
Returns a Span<T> containing the next count tokens.
This method may return a span shorter than count,
if the parser reaches the end of the input stream.
Declaration
public ReadOnlySpan<TToken> LookAhead(int count)Parameters
| Type | Name | Description |
|---|---|---|
count |
The number of tokens to advance. |
Returns
| Type | Description |
|---|---|
ReadOnlySpan<TToken> |
A ReadOnlySpan<T> containing the tokens. |
Rewind(Int32)
Return to a bookmark previously obtained from Bookmark() and discard it.
Declaration
public void Rewind(int bookmark)Parameters
| Type | Name | Description |
|---|---|---|
bookmark |
The location of the bookmark. |
SetError(Maybe<TToken>, Boolean, Int32, String)
Sets the error. Call this when your parser fails.
Declaration
public void SetError(Maybe<TToken> unexpected, bool eof, int errorLocation, string message)Parameters
| Type | Name | Description |
|---|---|---|
Maybe<TToken> |
unexpected |
The token that wasn't expected. |
eof |
Whether the parser unexpectedly reached the end of the input. |
|
errorLocation |
The location at which the parse error was encountered. |
|
message |
An error message. |