Beautify command line help output

[maettu-this]

Suggesting to limit the command line help's text width to the console width, in order to prevent line breaks and improve readability.

Some ideas taken from my own ArgsHandler making use of StringEx:

• Console.Out.Write(GetHelpText(Console.WindowWidth - 1)); // -1 ensures that lines that exactly match the number of characters do not lead to an empty line (due to the NewLine which is added).
• string GetHelpText(int maxWidth)
• string SplitIntoLines(int maxWidth, int indent, string text)

string SplitIntoLines(int maxWidth, int indent, string text)
{
	StringBuilder lines = new StringBuilder();

	int width = (maxWidth - indent);
	foreach (string line in StringEx.SplitLexically(text, width))
		lines.AppendLine(IndentSpace(indent) + line);

	return (lines.ToString());
}

string[] SplitLexically(string str, int desiredChunkLength)
{
	List<string> chunks = new List<string>();
	string[] newLineSeparators = new string[] { Environment.NewLine, "\n", "\r" };

	foreach (string paragraph in str.Split(newLineSeparators, StringSplitOptions.None))
		chunks.AddRange(SplitLexicallyWithoutTakingNewLineIntoAccount(paragraph, desiredChunkLength));

	return (chunks.ToArray());
}

string[] SplitLexicallyWithoutTakingNewLineIntoAccount(string str, int desiredChunkLength)
{
	List<int> spaces = new List<int>();

	// Retrieve all spaces within the string:
	int i = 0;
	while ((i = str.IndexOf(' ', i)) >= 0)
	{
		spaces.Add(i);
		i++;
	}

	// Add an extra space at the end of the string to ensure that the last chunk is split properly:
	spaces.Add(str.Length);

	// Split the string into the desired chunk size taking word boundaries into account:
	int startIndex = 0;
	List<string> chunks = new List<string>();
	while (startIndex < str.Length)
	{
		// Find the furthermost split position:
		int spaceIndex = spaces.FindLastIndex(value => (value <= (startIndex + desiredChunkLength)));
		
		int splitIndex;
		if (spaceIndex >= 0)
			splitIndex = spaces[spaceIndex];
		else
			splitIndex = (startIndex + desiredChunkLength);

		// Limit to split within the string and execute the split:
		splitIndex = Int32Ex.LimitToBounds(splitIndex, startIndex, str.Length);
		int length = (splitIndex - startIndex);
		chunks.Add(str.Substring(startIndex, length));
		startIndex += length;

		// Remove the already used spaces from the collection to ensure those spaces are not used again:
		if (spaceIndex >= 0)
		{
			spaces.RemoveRange(0, (spaceIndex + 1));
			startIndex++; // Advance an extra character to compensate the space.
		}
	}

	return (chunks.ToArray());
}

[oleg-shilo]

Excellent suggestion. Txs.
Scheduled for the next release

[oleg-shilo]

Done.

Thank you for sharing your code. It provided an excellent opportunity to improve CLI support.

I have used a slightly modified version of your SplitLexicallyWithoutTakingNewLineIntoAccount.
I have also introduced a very primitive "markup syntax" to allow sub-paragraphs (sub-indents) so common for CLI help content:

[maettu-this]

Great, looks very good now :-)