Read csv using Sylvan.Data.Csv

demo.csv

A;1;test;2022-11-11
B;something;else
A;2;test2;2022-11-12

Program.cs

using System.Diagnostics;
using Sylvan.Data.Csv;


var options = new CsvDataReaderOptions { HasHeaders = false, Delimiter = ';' };
using var csv = await CsvDataReader.CreateAsync("demo.csv", options);

var sw = Stopwatch.StartNew();
while(await csv.ReadAsync()) 
{
    var type = csv.GetString(0);

    object? row = type switch {
        "A" => CreateRecordA(csv),
        "B" => CreateRecordB(csv),
        _ => throw new InvalidOperationException($"Unknown record type '{type}'"),
    };

    Console.WriteLine(row);
}
sw.Stop();

Console.WriteLine($"Time taken: {sw.Elapsed}");

RecordA CreateRecordA(CsvDataReader csv) => new RecordA
{
    Id = csv.GetInt32(1),
    Name = csv.GetString(2),
    Date = csv.GetDateTime(3),
};

RecordB CreateRecordB(CsvDataReader csv) => new RecordB
{
    Name = csv.GetString(1),
    Description = csv.GetString(2),
};

public record struct RecordA
{
    public int Id;
    public string? Name;
    public DateTime Date;

    public override string ToString() => $"[{nameof(RecordA)}] {Id};{Name};{Date}";
}

public record struct RecordB
{
    public string? Name;
    public string? Description;

    public override string ToString() => $"[{nameof(RecordB)}] {Name};{Description}";
}