Move Spectre.Console.Cli to it's own package

src/Spectre.Console.Cli/Internal/TextBuffer.cs

@@ -0,0 +1,89 @@
+namespace Spectre.Console.Cli;
+
+internal sealed class TextBuffer : IDisposable
+{
+    // There is some kind of bug
+    private readonly StringReader _reader;
+
+    public bool ReachedEnd => _reader.Peek() == -1;
+    public string Original { get; }
+    public int Position { get; private set; }
+
+    public TextBuffer(string text)
+    {
+        _reader = new StringReader(text);
+        Original = text;
+        Position = 0;
+    }
+
+    public TextBuffer(TextBuffer? buffer, string text)
+    {
+        _reader = new StringReader(text);
+        Original = buffer != null ? buffer.Original + " " + text : text;
+        Position = buffer?.Position + 1 ?? 0;
+    }
+
+    public void Dispose()
+    {
+        _reader.Dispose();
+    }
+
+    public char Peek()
+    {
+        return (char)_reader.Peek();
+    }
+
+    public bool TryPeek(out char character)
+    {
+        var value = _reader.Peek();
+        if (value == -1)
+        {
+            character = '\0';
+            return false;
+        }
+
+        character = (char)value;
+        return true;
+    }
+
+    public void Consume()
+    {
+        EnsureNotAtEnd();
+        Read();
+    }
+
+    public void Consume(char character)
+    {
+        EnsureNotAtEnd();
+        if (Read() != character)
+        {
+            throw new InvalidOperationException($"Expected '{character}' token.");
+        }
+    }
+
+    public bool IsNext(char character)
+    {
+        if (TryPeek(out var result))
+        {
+            return result == character;
+        }
+
+        return false;
+    }
+
+    public char Read()
+    {
+        EnsureNotAtEnd();
+        var result = (char)_reader.Read();
+        Position++;
+        return result;
+    }
+
+    private void EnsureNotAtEnd()
+    {
+        if (ReachedEnd)
+        {
+            throw new InvalidOperationException("Can't read past the end of the buffer.");
+        }
+    }
+}