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agockeagocke
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Add IndentingBuilder for formatting source code (#26)
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5 files changed

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-71
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‎src/IndentingBuilder/IndentingBuilder.cs‎

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using System.Runtime.CompilerServices;
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using System.Text;
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namespace StaticCs;
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/// <summary>
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/// A string builder with automatic indentation support for multi-line text.
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/// Manages indentation levels with <see cref="Indent"/> and <see cref="Dedent"/> methods,
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/// and automatically applies the current indentation to appended content and interpolated strings.
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/// </summary>
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public sealed class IndentingBuilder : IComparable<IndentingBuilder>, IEquatable<IndentingBuilder>
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{
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public static readonly Encoding UTF8Encoding = new UTF8Encoding(encoderShouldEmitUTF8Identifier: false);
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private string _currentIndentWhitespace = "";
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private StringBuilder _stringBuilder;
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public IndentingBuilder(string s)
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{
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_stringBuilder = new StringBuilder(s);
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}
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public IndentingBuilder(SourceBuilderStringHandler s)
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{
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_currentIndentWhitespace = "";
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_stringBuilder = s._stringBuilder;
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}
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public IndentingBuilder()
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{
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_stringBuilder = new StringBuilder();
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}
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/// <summary>
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/// Removes trailing whitespace from every line and replace all newlines with
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/// Environment.NewLine.
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/// </summary>
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private void Normalize()
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{
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_stringBuilder.Replace("\r\n", "\n");
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// Remove trailing whitespace from every line
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int wsStart;
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for (int i = 0; i < _stringBuilder.Length; i++)
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{
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if (_stringBuilder[i] is '\n')
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{
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wsStart = i - 1;
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while (wsStart >= 0 && (_stringBuilder[wsStart] is ' ' or '\t'))
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{
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wsStart--;
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}
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wsStart++; // Move back to first whitespace
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if (wsStart < i)
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{
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int len = i - wsStart;
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_stringBuilder.Remove(wsStart, len);
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i -= len;
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}
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}
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}
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_stringBuilder.Replace("\n", Environment.NewLine);
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}
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public override string ToString()
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{
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Normalize();
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return _stringBuilder.ToString();
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}
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public void Append(
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[InterpolatedStringHandlerArgument("")]
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SourceBuilderStringHandler s)
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{
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// No work needed, the handler has already added the text to the string builder
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}
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public void Append(string s)
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{
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_stringBuilder.Append(_currentIndentWhitespace);
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Append(_stringBuilder, _currentIndentWhitespace, s);
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}
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public void Append(IndentingBuilder srcBuilder)
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{
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Append(srcBuilder.ToString());
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}
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private static void Append(
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StringBuilder builder,
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string currentIndentWhitespace,
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string str)
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{
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int start = 0;
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int nl;
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while (start < str.Length)
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{
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nl = str.IndexOf('\n', start);
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if (nl == -1)
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{
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nl = str.Length;
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}
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// Skip blank lines
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while (nl < str.Length && (str[nl] == '\n' || str[nl] == '\r'))
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{
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nl++;
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}
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if (start > 0)
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{
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builder.Append(currentIndentWhitespace);
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}
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builder.Append(str, start, nl - start);
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start = nl;
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}
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}
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public void AppendLine(
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[InterpolatedStringHandlerArgument("")]
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SourceBuilderStringHandler s)
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{
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Append(s);
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_stringBuilder.AppendLine();
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}
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public void AppendLine(string s)
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{
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Append(s);
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_stringBuilder.AppendLine();
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}
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public int CompareTo(IndentingBuilder? other)
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{
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if (other is null) return 1;
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var lenCmp = _stringBuilder.Length.CompareTo(other._stringBuilder.Length);
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if (lenCmp != 0)
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{
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return lenCmp;
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}
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for (int i = 0; i < _stringBuilder.Length; i++)
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{
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var cCmp = _stringBuilder[i].CompareTo(other._stringBuilder[i]);
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if (cCmp != 0)
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{
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return cCmp;
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}
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}
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return 0;
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}
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public void Indent()
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{
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_currentIndentWhitespace += " ";
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}
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public void Dedent()
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{
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_currentIndentWhitespace = _currentIndentWhitespace[..^4];
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}
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public bool Equals(IndentingBuilder? other)
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{
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return _stringBuilder.Equals(other?._stringBuilder);
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}
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public void AppendLine(IndentingBuilder deserialize)
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{
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Append(deserialize);
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_stringBuilder.AppendLine();
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}
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[InterpolatedStringHandler]
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public ref struct SourceBuilderStringHandler
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{
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internal readonly StringBuilder _stringBuilder;
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private readonly string _originalIndentWhitespace;
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private string _currentIndentWhitespace;
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private bool _isFirst = true;
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public SourceBuilderStringHandler(int literalLength, int formattedCount)
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{
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_stringBuilder = new StringBuilder(literalLength);
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_originalIndentWhitespace = "";
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_currentIndentWhitespace = "";
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}
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public SourceBuilderStringHandler(
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int literalLength,
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int formattedCount,
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IndentingBuilder sourceBuilder)
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{
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_stringBuilder = sourceBuilder._stringBuilder;
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_originalIndentWhitespace = sourceBuilder._currentIndentWhitespace;
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_currentIndentWhitespace = sourceBuilder._currentIndentWhitespace;
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}
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public void AppendLiteral(string s)
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{
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if (_isFirst)
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{
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_stringBuilder.Append(_currentIndentWhitespace);
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_isFirst = false;
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}
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Append(_stringBuilder, _currentIndentWhitespace, s);
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int last = s.LastIndexOf('\n');
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if (last == -1)
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{
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return;
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}
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var remaining = s.AsSpan(last + 1);
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foreach (var c in remaining)
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{
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if (c is not (' ' or '\t'))
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{
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return;
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}
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}
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_currentIndentWhitespace += remaining.ToString();
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}
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public void AppendFormatted<T>(T value)
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{
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if (_isFirst)
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{
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_stringBuilder.Append(_currentIndentWhitespace);
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_isFirst = false;
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}
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var str = value?.ToString();
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if (str is null)
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{
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_stringBuilder.Append(str);
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return;
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}
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Append(_stringBuilder, _currentIndentWhitespace, str);
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_currentIndentWhitespace = _originalIndentWhitespace;
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}
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}
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}

‎src/IndentingBuilder/IndentingBuilder.csproj‎

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<Project Sdk="Microsoft.NET.Sdk">
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<PropertyGroup>
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<TargetFrameworks>net8.0;netstandard2.0</TargetFrameworks>
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<ImplicitUsings>enable</ImplicitUsings>
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<Nullable>enable</Nullable>
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<LangVersion Condition="'$(TargetFramework)' == 'netstandard2.0'">12.0</LangVersion>
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</PropertyGroup>
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<PropertyGroup>
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<PackageId>StaticCS.IndentingBuilder</PackageId>
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<Version>0.1.0</Version>
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<IsPackable>true</IsPackable>
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<PackageLicenseExpression>MIT</PackageLicenseExpression>
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<RepositoryUrl>https://github.com/agocke/static-cs</RepositoryUrl>
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<Description>A string builder with automatic indentation support for multi-line text generation.</Description>
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<Authors>agocke</Authors>
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<PackageTags>string-builder;indentation;code-generation;text-generation</PackageTags>
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</PropertyGroup>
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<ItemGroup>
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<PackageReference Include="PolySharp" Version="1.15.0">
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<IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
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<PrivateAssets>all</PrivateAssets>
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</PackageReference>
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<PackageReference Include="System.Memory" Version="4.6.3" />
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</ItemGroup>
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</Project>

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