var text = """
           A;B;C;D;E;F
           Sep;🚀;1;1.2;0.1;0.5
           CSV;✅;2;2.2;0.2;1.5
           """;

using var reader = Sep.Reader().FromText(text);   // Infers separator 'Sep' from header
using var writer = reader.Spec.Writer().ToText(); // Writer defined from reader 'Spec'
                                                  // Use .FromFile(...)/ToFile(...) for files
var idx = reader.Header.IndexOf("B");
var nms = new[] { "E", "F" };

foreach (var readRow in reader)           // Read one row at a time
{
    var a = readRow["A"].Span;            // Column as ReadOnlySpan<char>
    var b = readRow[idx].ToString();      // Column to string (might be pooled)
    var c = readRow["C"].Parse<int>();    // Parse any T : ISpanParsable<T>
    var d = readRow["D"].Parse<float>();  // Parse float/double fast via csFastFloat
    var s = readRow[nms].Parse<double>(); // Parse multiple columns as Span<T>
                                          // - Sep handles array allocation and reuse
    foreach (ref var v in s) { v *= 10; }

    using var writeRow = writer.NewRow(); // Start new row. Row written on Dispose.
    writeRow["A"].Set(a);                 // Set by ReadOnlySpan<char>
    writeRow["B"].Set(b);                 // Set by string
    writeRow["C"].Set($"{c * 2}");        // Set via InterpolatedStringHandler, no allocs
    writeRow["D"].Format(d / 2);          // Format any T : ISpanFormattable
    writeRow[nms].Format(s);              // Format multiple columns directly
    // Columns are added on first access as ordered, header written when first row written
}

var expected = """
               A;B;C;D;E;F
               Sep;🚀;2;0.6;1;5
               CSV;✅;4;1.1;2;15
               
               """;                       // Empty line at end is for line ending,
                                          // which is always written.
Assert.AreEqual(expected, writer.ToString());

// Above example code is for demonstration purposes only.
// Short names and repeated constants are only for demonstration.

public readonly record struct Sep(char Separator);

using var reader = Sep.Reader().FromFile("titanic.csv");

using var reader = Sep.Auto.Reader().FromFile("titanic.csv");

using var reader = Sep.New(',').Reader().FromFile("titanic.csv");

var sep = new Sep(',');
using var reader = sep.Reader().FromFile("titanic.csv");

using var writer = Sep.Writer().ToFile("titanic.csv");

using var writer = Sep.New(',').Writer().ToFile("titanic.csv");

using var reader = Sep.Reader().FromFile("titanic.csv");
using var writer = reader.Spec.Writer().ToFile("titanic-survivors.csv");

using var reader = Sep.Reader(o => o).FromFile/FromText/From...;
var header = reader.Header;
var _ = header.IndexOf/IndicesOf/NamesStartingWith...;
foreach (var row in reader)
{
    var _ = row[colName/colNames].Span/ToString/Parse<T>...;
    var _ = row[colIndex/colIndices].Span/ToString/Parse<T>...;
}

/// <summary>
/// Specifies the separator used, if `null` then automatic detection 
/// is used based on first row in source.
/// </summary>
public Sep? Sep { get; init; } = null;
/// <summary>
/// Specifies the culture used for parsing. 
/// May be `null` for default culture.
/// </summary>
public CultureInfo? CultureInfo { get; init; } = SepDefaults.CultureInfo;
/// <summary>
/// Indicates whether the first row is a header row.
/// </summary>
public bool HasHeader { get; init; } = true;
/// <summary>
/// Specifies <see cref="IEqualityComparer{T}" /> to use 
/// for comparing header column names and looking up index.
/// </summary>
public IEqualityComparer<string> ColNameComparer { get; init; } = SepDefaults.ColNameComparer;
/// <summary>
/// Specifies the method factory used to convert a column span 
/// of `char`s to a `string`.
/// </summary>
public SepCreateToString CreateToString { get; init; } = SepToString.Direct;
/// <summary>
/// Disables using [csFastFloat](https://github.com/CarlVerret/csFastFloat)
/// for parsing `float` and `double`.
/// </summary>
public bool DisableFastFloat { get; init; } = false;
/// <summary>
/// Disables checking if column count is the same for all rows.
/// </summary>
public bool DisableColCountCheck { get; init; } = false;
/// <summary>
/// Disables detecting and parsing quotes.
/// </summary>
public bool DisableQuotesParsing { get; init; } = false;
/// <summary>
/// Unescape quotes on column access.
/// </summary>
/// <remarks>
/// When true, if a column starts with a quote then the two outermost quotes
/// are removed and every second inner quote is removed. Note that
/// unquote/unescape happens in-place, which means the <see
/// cref="SepReader.Row.Span" /> will be modified and contain "garbage"
/// state after unescaped cols before next col. This is for efficiency to
/// avoid allocating secondary memory for unescaped columns. Header
/// columns/names will also be unescaped.
/// Requires <see cref="DisableQuotesParsing"/> to be false.
/// </remarks>
public bool Unescape { get; init; } = false;

var text = """
           Key;Value
           A;"1
           2
           3"
           B;"Apple
           Banana
           Orange
           Pear"
           """;
using var reader = Sep.Reader().FromText(text);
foreach (var row in reader)
{
    // Hover over reader, row or col when breaking here
    var col = row[1];
    if (Debugger.IsAttached && row.RowIndex == 2) { Debugger.Break(); }
    Debug.WriteLine(col.ToString());
}

using var reader = Sep.Reader().FromText(text);
foreach (var row in reader)
{ }

using var reader = Sep.Reader().FromText(text);
while (reader.MoveNext())
{
    var row = reader.Current;
}

using var reader = Sep.Reader().FromText(text);
SepReader.Row[] rows = reader.ToArray();

using var reader = Sep.Reader().FromText(text);
SepReader[] rows = reader.ToArray();

var text = """
           Key;Value
           A;1.1
           B;2.2
           """;
var expected = new (string Key, double Value)[] {
    ("A", 1.1),
    ("B", 2.2),
};

using var reader = Sep.Reader().FromText(text);
var actual = Enumerate(reader).ToArray();

CollectionAssert.AreEqual(expected, actual);

static IEnumerable<(string Key, double Value)> Enumerate(SepReader reader)
{
    foreach (var row in reader)
    {
        yield return (row["Key"].ToString(), row["Value"].Parse<double>());
    }
}

var text = """
           Key;Value
           A;1.1
           B;2.2
           """;
var expected = new (string Key, double Value)[] {
    ("A", 1.1),
    ("B", 2.2),
};

using var reader = Sep.Reader().FromText(text);
var actual = Enumerate(reader,
    row => (row["Key"].ToString(), row["Value"].Parse<double>()))
    .ToArray();

CollectionAssert.AreEqual(expected, actual);

static IEnumerable<T> Enumerate<T>(SepReader reader, SepReader.RowFunc<T> select)
{
    foreach (var row in reader)
    {
        yield return select(row);
    }
}

var text = """
           Key;Value
           A;1.1
           B;2.2
           """;
var expected = new (string Key, double Value)[] {
    ("B", 2.2),
};

using var reader = Sep.Reader().FromText(text);
var actual = reader.Enumerate(
    row => (row["Key"].ToString(), row["Value"].Parse<double>()))
    .Where(kv => kv.Item1.StartsWith('B'))
    .ToArray();

CollectionAssert.AreEqual(expected, actual);

var text = """
           Key;Value
           A;1.1
           B;2.2
           """;
var expected = new (string Key, double Value)[] {
    ("B", 2.2),
};

using var reader = Sep.Reader().FromText(text);
var actual = Enumerate(reader).ToArray();

CollectionAssert.AreEqual(expected, actual);

static IEnumerable<(string Key, double Value)> Enumerate(SepReader reader)
{
    foreach (var row in reader)
    {
        var keyCol = row["Key"];
        if (keyCol.Span.StartsWith("B"))
        {
            yield return (keyCol.ToString(), row["Value"].Parse<double>());
        }
    }
}

static IEnumerable<T> Enumerate<T>(this SepReader reader, SepReader.RowTryFunc<T> trySelect)
{
    foreach (var row in reader)
    {
        if (trySelect(row, out var value))
        {
            yield return value;
        }
    }
}

var text = """
           Key;Value
           A;1.1
           B;2.2
           """;
var expected = new (string Key, double Value)[] {
    ("B", 2.2),
};

using var reader = Sep.Reader().FromText(text);
var actual = reader.Enumerate((SepReader.Row row, out (string Key, double Value) kv) =>
{
    var keyCol = row["Key"];
    if (keyCol.Span.StartsWith("B"))
    {
        kv = (keyCol.ToString(), row["Value"].Parse<double>());
        return true;
    }
    kv = default;
    return false;
}).ToArray();

CollectionAssert.AreEqual(expected, actual);

using var reader = Sep.Reader().FromFile("very-long.csv");
var results = reader.ParallelEnumerate(ParseRow)
                    .AsParallel().AsOrdered()
                    .Select(LoadData) // Expensive load
                    .ToList();

using var writer = Sep.Writer(o => o).ToFile/ToText/To...;
foreach (var data in EnumerateData())
{
    using var row = writer.NewRow();
    var _ = row[colName/colNames].Set/Format<T>...;
    var _ = row[colIndex/colIndices].Set/Format<T>...;
}

/// <summary>
/// Specifies the separator used.
/// </summary>
public Sep Sep { get; init; }
/// <summary>
/// Specifies the culture used for parsing. 
/// May be `null` for default culture.
/// </summary>
public CultureInfo? CultureInfo { get; init; }
/// <summary>
/// Specifies whether to write a header row 
/// before data rows. Requires all columns 
/// to have a name. Otherwise, columns can be
/// added by indexing alone.
/// </summary>
public bool WriteHeader { get; init; } = true;

using var reader = Sep.Reader(o => o with
{
    HasHeader = false,
    CreateToString = SepToString.PoolPerCol(maximumStringLength: 128),
})
.From(CreateReader());

using var reader = Sep.Reader().From(Reader.CreateReader());

var groundTruthColNames = reader.Header.NamesStartingWith("GT_");
var resultColNames = groundTruthColNames.Select(n =>
    n.Replace("GT_", "RE_", StringComparison.Ordinal))
    .ToArray();

var sum = 0.0;
var count = 0;
foreach (var row in reader)
{
    var gts = row[groundTruthColNames].Parse<float>();
    var res = row[resultColNames].Parse<float>();

    sum += MeanSquaredError(gts, res);
    ++count;
}
return sum / count;

var text = """
           A;B;C;D;E;F
           Sep;🚀;1;1.2;0.1;0.5
           CSV;✅;2;2.2;0.2;1.5
           
           """; // Empty line at end is for line ending

using var reader = Sep.Reader().FromText(text);
using var writer = reader.Spec.Writer().ToText();
foreach (var readRow in reader)
{
    using var writeRow = writer.NewRow(readRow);
}
Assert.AreEqual(text, writer.ToString());

var text = """
           A
           1
           2

           3


           4
           
           """; // Empty line at end is for line ending
var expected = new[] { 1, 2, 3, 4 };

// Disable col count check to allow empty rows
using var reader = Sep.Reader(o => o with { DisableColCountCheck = true }).FromText(text);
var actual = new List<int>();
foreach (var row in reader)
{
    // Skip empty row
    if (row.Span.Length == 0) { continue; }

    actual.Add(row["A"].Parse<int>());
}
CollectionAssert.AreEqual(expected, actual);

var text = """
           C
           1
           2
           """;

using var reader = Sep.Reader().FromText(text);
var squaredSum = 0;
// Use Enumerate to avoid referencing SepReader.Row in async context
foreach (var value in reader.Enumerate(row => row["C"].Parse<int>()))
{
    squaredSum += await Task.Run(() => value * value);
}
Assert.AreEqual(5, squaredSum);

var text = """
           C
           1
           2
           """;

using var reader = Sep.Reader().FromText(text);
var squaredSum = 0;
// Use custom local function Enumerate to avoid referencing
// SepReader.Row in async context
foreach (var value in Enumerate(reader))
{
    squaredSum += await Task.Run(() => value * value);
}
Assert.AreEqual(5, squaredSum);

static IEnumerable<int> Enumerate(SepReader reader)
{
    foreach (var r in reader) { yield return r["C"].Parse<int>(); }
}

[assembly: System.CLSCompliant(false)]
[assembly: System.Reflection.AssemblyMetadata("IsTrimmable", "True")]
[assembly: System.Reflection.AssemblyMetadata("RepositoryUrl", "https://github.com/nietras/Sep/")]
[assembly: System.Resources.NeutralResourcesLanguage("en")]
[assembly: System.Runtime.CompilerServices.InternalsVisibleTo("Sep.Benchmarks")]
[assembly: System.Runtime.CompilerServices.InternalsVisibleTo("Sep.ComparisonBenchmarks")]
[assembly: System.Runtime.CompilerServices.InternalsVisibleTo("Sep.Test")]
[assembly: System.Runtime.Versioning.TargetFramework(".NETCoreApp,Version=v8.0", FrameworkDisplayName=".NET 8.0")]
namespace nietras.SeparatedValues
{
    public readonly struct Sep : System.IEquatable<nietras.SeparatedValues.Sep>
    {
        public Sep() { }
        public Sep(char separator) { }
        public char Separator { get; init; }
        public static nietras.SeparatedValues.Sep? Auto { get; }
        public static nietras.SeparatedValues.Sep Default { get; }
        public static nietras.SeparatedValues.Sep New(char separator) { }
        public static nietras.SeparatedValues.SepReaderOptions Reader() { }
        public static nietras.SeparatedValues.SepReaderOptions Reader(System.Func<nietras.SeparatedValues.SepReaderOptions, nietras.SeparatedValues.SepReaderOptions> configure) { }
        public static nietras.SeparatedValues.SepWriterOptions Writer() { }
        public static nietras.SeparatedValues.SepWriterOptions Writer(System.Func<nietras.SeparatedValues.SepWriterOptions, nietras.SeparatedValues.SepWriterOptions> configure) { }
    }
    public delegate nietras.SeparatedValues.SepToString SepCreateToString(nietras.SeparatedValues.SepReaderHeader? maybeHeader, int colCount);
    public static class SepDefaults
    {
        public static System.StringComparer ColNameComparer { get; }
        public static System.Globalization.CultureInfo CultureInfo { get; }
        public static char Separator { get; }
    }
    [System.Diagnostics.DebuggerDisplay("{DebuggerDisplay,nq}")]
    public sealed class SepReader : nietras.SeparatedValues.SepReaderState
    {
        public nietras.SeparatedValues.SepReader.Row Current { get; }
        public bool HasHeader { get; }
        public bool HasRows { get; }
        public nietras.SeparatedValues.SepReaderHeader Header { get; }
        public bool IsEmpty { get; }
        public nietras.SeparatedValues.SepSpec Spec { get; }
        public nietras.SeparatedValues.SepReader GetEnumerator() { }
        public bool MoveNext() { }
        public string ToString(int index) { }
        [System.Diagnostics.DebuggerDisplay("{DebuggerDisplay}")]
        [System.Obsolete("Types with embedded references are not supported in this version of your compiler" +
            ".", true)]
        [System.Runtime.CompilerServices.CompilerFeatureRequired("RefStructs")]
        [System.Runtime.CompilerServices.IsByRefLike]
        public readonly struct Col
        {
            public System.ReadOnlySpan<char> Span { get; }
            public T Parse<T>()
                where T : System.ISpanParsable<T> { }
            public override string ToString() { }
            public T? TryParse<T>()
                where T :  struct, System.ISpanParsable<T> { }
            public bool TryParse<T>(out T value)
                where T : System.ISpanParsable<T> { }
        }
        [System.Obsolete("Types with embedded references are not supported in this version of your compiler" +
            ".", true)]
        [System.Runtime.CompilerServices.CompilerFeatureRequired("RefStructs")]
        [System.Runtime.CompilerServices.IsByRefLike]
        public readonly struct Cols
        {
            public int Count { get; }
            public nietras.SeparatedValues.SepReader.Col this[int index] { get; }
            public System.Span<T> Parse<T>()
                where T : System.ISpanParsable<T> { }
            public void Parse<T>(System.Span<T> span)
                where T : System.ISpanParsable<T> { }
            public T[] ParseToArray<T>()
                where T : System.ISpanParsable<T> { }
            public System.Span<T> Select<T>(method selector) { }
            public System.Span<T> Select<T>(nietras.SeparatedValues.SepReader.ColFunc<T> selector) { }
            public System.Span<string> ToStrings() { }
            public string[] ToStringsArray() { }
            public System.Span<T?> TryParse<T>()
                where T :  struct, System.ISpanParsable<T> { }
            public void TryParse<T>(System.Span<T?> span)
                where T :  struct, System.ISpanParsable<T> { }
        }
        [System.Diagnostics.DebuggerDisplay("{DebuggerDisplayPrefix,nq}{Span}")]
        [System.Diagnostics.DebuggerTypeProxy(typeof(nietras.SeparatedValues.SepReader.Row.DebugView))]
        [System.Obsolete("Types with embedded references are not supported in this version of your compiler" +
            ".", true)]
        [System.Runtime.CompilerServices.CompilerFeatureRequired("RefStructs")]
        [System.Runtime.CompilerServices.IsByRefLike]
        public readonly struct Row
        {
            public int ColCount { get; }
            public nietras.SeparatedValues.SepReader.Col this[int index] { get; }
            public nietras.SeparatedValues.SepReader.Col this[System.Index index] { get; }
            public nietras.SeparatedValues.SepReader.Col this[string colName] { get; }
            public nietras.SeparatedValues.SepReader.Cols this[System.Range range] { get; }
            public nietras.SeparatedValues.SepReader.Cols this[System.ReadOnlySpan<int> indices] { get; }
            public nietras.SeparatedValues.SepReader.Cols this[System.Collections.Generic.IReadOnlyList<int> indices] { get; }
            public nietras.SeparatedValues.SepReader.Cols this[int[] indices] { get; }
            public nietras.SeparatedValues.SepReader.Cols this[System.ReadOnlySpan<string> colNames] { get; }
            public nietras.SeparatedValues.SepReader.Cols this[System.Collections.Generic.IReadOnlyList<string> colNames] { get; }
            public nietras.SeparatedValues.SepReader.Cols this[string[] colNames] { get; }
            public int LineNumberFrom { get; }
            public int LineNumberToExcl { get; }
            public int RowIndex { get; }
            public System.ReadOnlySpan<char> Span { get; }
            public System.Func<int, string> UnsafeToStringDelegate { get; }
            public override string ToString() { }
        }
        public delegate void ColAction(nietras.SeparatedValues.SepReader.Col col);
        public delegate T ColFunc<T>(nietras.SeparatedValues.SepReader.Col col);
        public delegate void ColsAction(nietras.SeparatedValues.SepReader.Cols col);
        public delegate void RowAction(nietras.SeparatedValues.SepReader.Row row);
        public delegate T RowFunc<T>(nietras.SeparatedValues.SepReader.Row row);
        public delegate bool RowTryFunc<T>(nietras.SeparatedValues.SepReader.Row row, out T value);
    }
    public static class SepReaderExtensions
    {
        public static System.Collections.Generic.IEnumerable<T> Enumerate<T>(this nietras.SeparatedValues.SepReader reader, nietras.SeparatedValues.SepReader.RowFunc<T> select) { }
        public static System.Collections.Generic.IEnumerable<T> Enumerate<T>(this nietras.SeparatedValues.SepReader reader, nietras.SeparatedValues.SepReader.RowTryFunc<T> trySelect) { }
        public static nietras.SeparatedValues.SepReader From(this nietras.SeparatedValues.SepReaderOptions options, byte[] buffer) { }
        public static nietras.SeparatedValues.SepReader From(this nietras.SeparatedValues.SepReaderOptions options, System.IO.Stream stream) { }
        public static nietras.SeparatedValues.SepReader From(this nietras.SeparatedValues.SepReaderOptions options, System.IO.TextReader reader) { }
        public static nietras.SeparatedValues.SepReader From(this nietras.SeparatedValues.SepReaderOptions options, string name, System.Func<string, System.IO.Stream> nameToStream) { }
        public static nietras.SeparatedValues.SepReader From(this nietras.SeparatedValues.SepReaderOptions options, string name, System.Func<string, System.IO.TextReader> nameToReader) { }
        public static nietras.SeparatedValues.SepReader FromFile(this nietras.SeparatedValues.SepReaderOptions options, string filePath) { }
        public static nietras.SeparatedValues.SepReader FromText(this nietras.SeparatedValues.SepReaderOptions options, string text) { }
        public static System.Collections.Generic.IEnumerable<T> ParallelEnumerate<T>(this nietras.SeparatedValues.SepReader reader, nietras.SeparatedValues.SepReader.RowFunc<T> select) { }
        public static System.Collections.Generic.IEnumerable<T> ParallelEnumerate<T>(this nietras.SeparatedValues.SepReader reader, nietras.SeparatedValues.SepReader.RowTryFunc<T> trySelect) { }
        public static System.Collections.Generic.IEnumerable<T> ParallelEnumerate<T>(this nietras.SeparatedValues.SepReader reader, nietras.SeparatedValues.SepReader.RowFunc<T> select, int degreeOfParallism) { }
        public static System.Collections.Generic.IEnumerable<T> ParallelEnumerate<T>(this nietras.SeparatedValues.SepReader reader, nietras.SeparatedValues.SepReader.RowTryFunc<T> trySelect, int degreeOfParallism) { }
        public static nietras.SeparatedValues.SepReaderOptions Reader(this nietras.SeparatedValues.Sep sep) { }
        public static nietras.SeparatedValues.SepReaderOptions Reader(this nietras.SeparatedValues.Sep? sep) { }
        public static nietras.SeparatedValues.SepReaderOptions Reader(this nietras.SeparatedValues.SepSpec spec) { }
        public static nietras.SeparatedValues.SepReaderOptions Reader(this nietras.SeparatedValues.Sep sep, System.Func<nietras.SeparatedValues.SepReaderOptions, nietras.SeparatedValues.SepReaderOptions> configure) { }
        public static nietras.SeparatedValues.SepReaderOptions Reader(this nietras.SeparatedValues.Sep? sep, System.Func<nietras.SeparatedValues.SepReaderOptions, nietras.SeparatedValues.SepReaderOptions> configure) { }
        public static nietras.SeparatedValues.SepReaderOptions Reader(this nietras.SeparatedValues.SepSpec spec, System.Func<nietras.SeparatedValues.SepReaderOptions, nietras.SeparatedValues.SepReaderOptions> configure) { }
    }
    public sealed class SepReaderHeader
    {
        public System.Collections.Generic.IReadOnlyList<string> ColNames { get; }
        public bool IsEmpty { get; }
        public static nietras.SeparatedValues.SepReaderHeader Empty { get; }
        public int IndexOf(string colName) { }
        public int[] IndicesOf(System.Collections.Generic.IReadOnlyList<string> colNames) { }
        public int[] IndicesOf(System.ReadOnlySpan<string> colNames) { }
        public int[] IndicesOf(params string[] colNames) { }
        public void IndicesOf(System.ReadOnlySpan<string> colNames, System.Span<int> colIndices) { }
        public System.Collections.Generic.IReadOnlyList<string> NamesStartingWith(string prefix, System.StringComparison comparison = 4) { }
        public override string ToString() { }
        public bool TryIndexOf(string colName, out int colIndex) { }
    }
    public readonly struct SepReaderOptions : System.IEquatable<nietras.SeparatedValues.SepReaderOptions>
    {
        public SepReaderOptions() { }
        public SepReaderOptions(nietras.SeparatedValues.Sep? sep) { }
        public System.Collections.Generic.IEqualityComparer<string> ColNameComparer { get; init; }
        public nietras.SeparatedValues.SepCreateToString CreateToString { get; init; }
        public System.Globalization.CultureInfo? CultureInfo { get; init; }
        public bool DisableColCountCheck { get; init; }
        public bool DisableFastFloat { get; init; }
        public bool DisableQuotesParsing { get; init; }
        public bool HasHeader { get; init; }
        public nietras.SeparatedValues.Sep? Sep { get; init; }
        public bool Unescape { get; init; }
    }
    public class SepReaderState : System.IDisposable
    {
        public void Dispose() { }
    }
    public static class SepReaderWriterExtensions
    {
        public static void CopyTo(this nietras.SeparatedValues.SepReader.Row readerRow, nietras.SeparatedValues.SepWriter.Row writerRow) { }
        public static nietras.SeparatedValues.SepWriter.Row NewRow(this nietras.SeparatedValues.SepWriter writer, nietras.SeparatedValues.SepReader.Row rowToCopy) { }
    }
    public readonly struct SepSpec : System.IEquatable<nietras.SeparatedValues.SepSpec>
    {
        public SepSpec() { }
        public SepSpec(nietras.SeparatedValues.Sep sep, System.Globalization.CultureInfo? cultureInfo) { }
        public System.Globalization.CultureInfo? CultureInfo { get; init; }
        public nietras.SeparatedValues.Sep Sep { get; init; }
    }
    public abstract class SepToString : System.IDisposable
    {
        protected SepToString() { }
        public virtual bool IsThreadSafe { get; }
        public static nietras.SeparatedValues.SepCreateToString Direct { get; }
        public void Dispose() { }
        protected virtual void Dispose(bool disposing) { }
        public abstract string ToString(System.ReadOnlySpan<char> colSpan, int colIndex);
        public static nietras.SeparatedValues.SepCreateToString OnePool(int maximumStringLength = 32, int initialCapacity = 64, int maximumCapacity = 4096) { }
        public static nietras.SeparatedValues.SepCreateToString PoolPerCol(int maximumStringLength = 32, int initialCapacity = 64, int maximumCapacity = 4096) { }
        public static nietras.SeparatedValues.SepCreateToString PoolPerColThreadSafe(int maximumStringLength = 32, int initialCapacity = 64, int maximumCapacity = 4096) { }
        public static nietras.SeparatedValues.SepCreateToString PoolPerColThreadSafeFixedCapacity(int maximumStringLength = 32, int capacity = 2048) { }
    }
    public sealed class SepWriter : System.IDisposable
    {
        public nietras.SeparatedValues.SepWriterHeader Header { get; }
        public nietras.SeparatedValues.SepSpec Spec { get; }
        public void Dispose() { }
        public void Flush() { }
        public nietras.SeparatedValues.SepWriter.Row NewRow() { }
        public override string ToString() { }
        [System.Obsolete("Types with embedded references are not supported in this version of your compiler" +
            ".", true)]
        [System.Runtime.CompilerServices.CompilerFeatureRequired("RefStructs")]
        [System.Runtime.CompilerServices.IsByRefLike]
        public struct Row
        {
            public nietras.SeparatedValues.SepWriter.Col this[int colIndex] { get; }
            public nietras.SeparatedValues.SepWriter.Col this[string colName] { get; }
            public nietras.SeparatedValues.SepWriter.Cols this[System.ReadOnlySpan<int> indices] { get; }
            public nietras.SeparatedValues.SepWriter.Cols this[System.ReadOnlySpan<string> colNames] { get; }
            public nietras.SeparatedValues.SepWriter.Cols this[System.Collections.Generic.IReadOnlyList<string> colNames] { get; }
            public nietras.SeparatedValues.SepWriter.Cols this[string[] colNames] { get; }
            public void Dispose() { }
        }
        [System.Obsolete("Types with embedded references are not supported in this version of your compiler" +
            ".", true)]
        [System.Runtime.CompilerServices.CompilerFeatureRequired("RefStructs")]
        [System.Runtime.CompilerServices.IsByRefLike]
        public readonly struct Col
        {
            public void Format<T>(T value)
                where T : System.ISpanFormattable { }
            public void Set(System.ReadOnlySpan<char> span) { }
            public void Set([System.Runtime.CompilerServices.InterpolatedStringHandlerArgument("")] ref nietras.SeparatedValues.SepWriter.Col.FormatInterpolatedStringHandler handler) { }
            public void Set(System.IFormatProvider? provider, [System.Runtime.CompilerServices.InterpolatedStringHandlerArgument(new string?[]?[] {
                    "",
                    "provider"})] ref nietras.SeparatedValues.SepWriter.Col.FormatInterpolatedStringHandler handler) { }
            [System.Runtime.CompilerServices.InterpolatedStringHandler]
            public readonly struct FormatInterpolatedStringHandler
            {
                public FormatInterpolatedStringHandler(int literalLength, int formattedCount, nietras.SeparatedValues.SepWriter.Col col) { }
                public FormatInterpolatedStringHandler(int literalLength, int formattedCount, nietras.SeparatedValues.SepWriter.Col col, System.IFormatProvider? provider) { }
                public void AppendFormatted(System.ReadOnlySpan<char> value) { }
                public void AppendFormatted(string? value) { }
                public void AppendFormatted(System.ReadOnlySpan<char> value, int alignment = 0, string? format = null) { }
                public void AppendFormatted(object? value, int alignment = 0, string? format = null) { }
                public void AppendFormatted(string? value, int alignment = 0, string? format = null) { }
                public void AppendFormatted<T>(T value) { }
                public void AppendFormatted<T>(T value, int alignment) { }
                public void AppendFormatted<T>(T value, string? format) { }
                public void AppendFormatted<T>(T value, int alignment, string? format) { }
                public void AppendLiteral(string value) { }
            }
        }
        [System.Obsolete("Types with embedded references are not supported in this version of your compiler" +
            ".", true)]
        [System.Runtime.CompilerServices.CompilerFeatureRequired("RefStructs")]
        [System.Runtime.CompilerServices.IsByRefLike]
        public readonly struct Cols
        {
            public int Count { get; }
            public nietras.SeparatedValues.SepWriter.Col this[int colIndex] { get; }
            public void Format<T>(System.Collections.Generic.IReadOnlyList<T> values)
                where T : System.ISpanFormattable { }
            public void Format<T>(System.ReadOnlySpan<T> values)
                where T : System.ISpanFormattable { }
            public void Format<T>(System.Span<T> values)
                where T : System.ISpanFormattable { }
            public void Format<T>(T[] values)
                where T : System.ISpanFormattable { }
            public void Format<T>(System.ReadOnlySpan<T> values, nietras.SeparatedValues.SepWriter.ColAction<T> format) { }
            public void Set(System.Collections.Generic.IReadOnlyList<string> values) { }
            public void Set(System.ReadOnlySpan<string> values) { }
            public void Set(string[] values) { }
            public void Set(nietras.SeparatedValues.SepReader.Cols cols) { }
        }
        public delegate void ColAction(nietras.SeparatedValues.SepWriter.Col col);
        public delegate void ColAction<T>(nietras.SeparatedValues.SepWriter.Col col, T value);
        public delegate void RowAction(nietras.SeparatedValues.SepWriter.Row row);
    }
    public static class SepWriterExtensions
    {
        public static nietras.SeparatedValues.SepWriter To(this nietras.SeparatedValues.SepWriterOptions options, System.IO.Stream stream) { }
        public static nietras.SeparatedValues.SepWriter To(this nietras.SeparatedValues.SepWriterOptions options, System.IO.TextWriter writer) { }
        public static nietras.SeparatedValues.SepWriter To(this nietras.SeparatedValues.SepWriterOptions options, System.IO.Stream stream, bool leaveOpen) { }
        public static nietras.SeparatedValues.SepWriter To(this nietras.SeparatedValues.SepWriterOptions options, System.IO.TextWriter writer, bool leaveOpen) { }
        public static nietras.SeparatedValues.SepWriter ToFile(this nietras.SeparatedValues.SepWriterOptions options, string filePath) { }
        public static nietras.SeparatedValues.SepWriter ToText(this nietras.SeparatedValues.SepWriterOptions options) { }
        public static nietras.SeparatedValues.SepWriter ToText(this nietras.SeparatedValues.SepWriterOptions options, int capacity) { }
        public static nietras.SeparatedValues.SepWriterOptions Writer(this nietras.SeparatedValues.Sep sep) { }
        public static nietras.SeparatedValues.SepWriterOptions Writer(this nietras.SeparatedValues.SepSpec spec) { }
        public static nietras.SeparatedValues.SepWriterOptions Writer(this nietras.SeparatedValues.Sep sep, System.Func<nietras.SeparatedValues.SepWriterOptions, nietras.SeparatedValues.SepWriterOptions> configure) { }
        public static nietras.SeparatedValues.SepWriterOptions Writer(this nietras.SeparatedValues.SepSpec spec, System.Func<nietras.SeparatedValues.SepWriterOptions, nietras.SeparatedValues.SepWriterOptions> configure) { }
    }
    [System.Diagnostics.DebuggerDisplay("{DebuggerDisplay,nq}")]
    [System.Diagnostics.DebuggerTypeProxy(typeof(nietras.SeparatedValues.SepWriterHeader.DebugView))]
    public sealed class SepWriterHeader
    {
        public void Add(System.Collections.Generic.IReadOnlyList<string> colNames) { }
        public void Add(System.ReadOnlySpan<string> colNames) { }
        public void Add(string colName) { }
        public void Add(string[] colNames) { }
        public void Write() { }
    }
    public readonly struct SepWriterOptions : System.IEquatable<nietras.SeparatedValues.SepWriterOptions>
    {
        public SepWriterOptions() { }
        public SepWriterOptions(nietras.SeparatedValues.Sep sep) { }
        public System.Globalization.CultureInfo? CultureInfo { get; init; }
        public nietras.SeparatedValues.Sep Sep { get; init; }
        public bool WriteHeader { get; init; }
    }
}