Word wrapping implementation.

This was in my scratch notes.  I have to get it building again.

word_wrap.cpp

@@ -0,0 +1,66 @@
+static_assert( __cplusplus > 2020 );
+
+#include "word_wrap.h"
+
+namespace Alepha::Cavorite  ::detail::  word_wrap
+{
+	namespace
+	{
+		// Returns the number of chars in the line just written to.
+		std::size_t
+		applyWordToLine( const std::size_t maximumWidth, const std::size_t nextLineOffset, const std::size_t currentLineWidth, std::string &&word, std::string &result )
+		{
+			if( word.empty() ) return currentLineWidth;
+
+			const auto lineWidth= evaluate <=[&]
+			{
+				if( currentLineWidth + word.size() > maximumWidth )
+				{
+					result+= '\n';
+					std::fill_n( back_inserter( result ), ' ', nextLineOffset );
+					return nextLineOffset;
+				}
+				else return currentLineWidth;
+			};
+
+			const auto rv= lineWidth + word.size();
+			result+= std::move( word );
+			return rv;
+		}
+	}
+
+	std::string
+	exports::wordWrap( const std::string &text, const std::size_t width, const std::size_t nextLineOffset )
+	{
+		auto putWord= [[nodiscard]] [width, nextLineOffset]( std::string &&word, std::string &line, const std::size_t lineLength )
+		{
+			return applyWordToLine( width, nextLineOffset, line.size(), std::move( word ), line );
+		};
+
+		std::string result;
+		std::string word;
+		std::size_t lineLength= 0;
+		for( const char ch: text )
+		{
+			if( ch == '\n' )
+			{
+				std::ignore= putWord( std::move( word ), result, lineLength );
+				word.clear();
+				lineLength= 0;
+			}
+			else if( ch == ' ' )
+			{
+				lineLength= putWord( std::move( word ), result, lineLength );
+				word.clear();
+				if( lineLength < width )
+				{
+					line+= ' ';
+					lineLength++;
+				}
+			}
+			else word+= ch;
+		}
+		if( not word.empty() ) std::ignore= putWord( std::move( word ), result, lineLength );
+		return result;
+	}
+}

word_wrap.h

@@ -0,0 +1,13 @@
+static_assert( __cplusplus > 2020'00 );
+
+#pragma once
+
+#include <cstddef>
+
+namespace Alepha::inline Cavorite  ::detail::  word_wrap
+{
+	inline namespace exports
+	{
+		std::string wordWrap( const std::string &text, std::size_t width, std::size_t nextLineOffset= 0 );
+	}
+}