CanonSharp/CanonSharp.Tests/CombinatorsTests/ModifierParserTests.cs

using CanonSharp.Combinator;
using CanonSharp.Combinator.Abstractions;
using CanonSharp.Combinator.Extensions;
using CanonSharp.Tests.Utils;
using static CanonSharp.Combinator.ParserBuilder;
using static CanonSharp.Combinator.Text.TextParserBuilder;

namespace CanonSharp.Tests.CombinatorsTests;

public class ModifierParserTests : ParserTestsBase
{
    [Fact]
    public void DoTest()
    {
        IParser<char, char> parser = Token('a').Do(x => Assert.Equal('a', x)).Do(x => Assert.Equal('a', x),
            failedResult => Assert.ThrowsAny<ParseException>(() => failedResult.Value));

        ValidateSuccessfulResult(parser, 'a', "abc");
        ValidateFailedResult(parser, "bcd");
    }

    [Fact]
    public void LookAheadTest()
    {
        IParser<char, char> parser = Token('a').LookAhead().Next(_ => Token('a'), _ => Token('b'));
        ValidateSuccessfulResult(parser, 'a', "abc");
        ValidateSuccessfulResult(parser, 'b', "bcd");
    }

    [Fact]
    public void NotTest()
    {
        IParser<char, char> parser = Token('a').Not('b');
        ValidateSuccessfulResult(parser, 'b', "bcd");

        parser = Token('a').Not().Bind(_ => Token('b'));
        ValidateSuccessfulResult(parser, 'b', "bcd");
    }

    [Fact]
    public void TryTest()
    {
        IParser<char, string> parser = String("abc").Try("cde");
        ValidateSuccessfulResult(parser, "abc", "abc");
        ValidateSuccessfulResult(parser, "cde", "cde");

        parser = String("abc").Try(_ => "cde");
        ValidateSuccessfulResult(parser, "abc", "abc");
        ValidateSuccessfulResult(parser, "cde", "cde");
    }
}