Remove ISeekable from Else/ElseError

src/Parlot/Fluent/Else.cs

@@ -1,34 +1,20 @@
 using Parlot.Compilation;
-using Parlot.Rewriting;
 using System.Linq.Expressions;
 
 namespace Parlot.Fluent;
 
 /// <summary>
 /// Returns a default value if the previous parser failed.
 /// </summary>
-public sealed class Else<T> : Parser<T>, ICompilable, ISeekable
+public sealed class Else<T> : Parser<T>, ICompilable
 {
     private readonly Parser<T> _parser;
     private readonly T _value;
 
-    public bool CanSeek { get; }
-
-    public char[] ExpectedChars { get; } = [];
-
-    public bool SkipWhitespace { get; }
-
     public Else(Parser<T> parser, T value)
     {
         _parser = parser;
         _value = value;
-
-        if (_parser is ISeekable seekable)
-        {
-            CanSeek = seekable.CanSeek;
-            ExpectedChars = seekable.ExpectedChars;
-            SkipWhitespace = seekable.SkipWhitespace;
-        }
     }
 
     public override bool Parse(ParseContext context, ref ParseResult<T> result)

src/Parlot/Fluent/Error.cs

@@ -8,28 +8,15 @@
 
 namespace Parlot.Fluent;
 
-public sealed class ElseError<T> : Parser<T>, ICompilable, ISeekable
+public sealed class ElseError<T> : Parser<T>, ICompilable
 {
     private readonly Parser<T> _parser;
     private readonly string _message;
 
-    public bool CanSeek { get; }
-
-    public char[] ExpectedChars { get; } = [];
-
-    public bool SkipWhitespace { get; }
-
     public ElseError(Parser<T> parser, string message)
     {
         _parser = parser ?? throw new ArgumentNullException(nameof(parser));
         _message = message;
-
-        if (_parser is ISeekable seekable)
-        {
-            CanSeek = seekable.CanSeek;
-            ExpectedChars = seekable.ExpectedChars;
-            SkipWhitespace = seekable.SkipWhitespace;
-        }
     }
 
     public override bool Parse(ParseContext context, ref ParseResult<T> result)

test/Parlot.Tests/FluentTests.cs

@@ -1172,4 +1172,18 @@ public void AnyOfShouldResetPositionWhenFalse()
              .And(Literals.AnyOf("Z"))
              .TryParse("aaaZZ", out _));
     }
+
+    [Fact]
+    public void ElseErrorShouldNotBeSeekable()
+    {
+        Parser<char> a = Terms.Char('a');
+        Parser<char> b = Terms.Char('b');
+        Parser<object> c = a.Then<object>();
+
+        // Use two parsers to ensure OneOf tries to build a lookup table
+        var parser = OneOf(a.ElseError("Error"), b);
+
+        Assert.True(parser.TryParse("a", out _));
+        Assert.Throws<ParseException>(() => parser.Parse("b"));
+    }
 }