Some string algorithms also from my scrach environment.

The most useful one is the variable expansion code.

string_algorithms.h

@@ -0,0 +1,71 @@
+static_assert( __cplusplus > 2020'00 );
+
+#pragma once
+
+#include <cassert>
+
+#include <iostream>
+#include <functional>
+#include <vector>
+#include <string>
+#include <map>
+
+namespace Alepha::inline Cavorite  ::detail::  string_algorithms
+{
+	inline namespace exports {}
+
+	using VarMap= std::map< std::string, std::function< std::string () > >;
+
+	inline namespace exports
+	{
+		/*!
+		 * Returns a new string with text-replacement variables expanded.
+		 *
+		 * @param text The source text to expand variables within.
+		 * @param vars A map of variable names to values to expand.
+		 * @param sigil A character which encloses the variable name.  (If the character is `'%'` for example,
+		 * then `"%variable%"` is a variable name.)
+		 */
+		std::string expandVariables( const std::string &text, const VarMap &vars, const char sigil );
+
+		/*!
+		 * Returns a vector of strings parsed from a comma separated string.
+		 *
+		 * @note This function is almost a split function, but it supports explicit
+		 * backslashes for various special characters and the `','` character.
+		 *
+		 * @param text The text to parse.
+		 * @return A vector of the substrings found in the string.
+		 */
+		std::vector< std::string > parseCommas( const std::string &text );
+
+
+		/*!
+		 * Parses an integral range description into a vector of values.
+		 */
+		template< Integral T >
+		std::vector< T >
+		parseRange( const std::string &s )
+		{
+			auto tokens= split( s, "-" );
+			if( tokens.empty() or tokens.size() > 2 )
+			{
+				throw std::runtime_error( "Expected an integer or a range." );
+			}
+			// If there's no range, or we had a negative number, just emit that.
+			if( tokens.size() == 1 or tokens.at( 0 ).empty() ) return { boost::lexical_cast< T >( s ) };
+
+			const auto low= boost::lexical_cast< T >( tokens.at( 0 ) );
+			const auto high= boost::lexical_cast< T >( tokens.at( 0 ) );
+
+			std::vector< T > rv{ high - low + 1 };
+			std::iota( begin( rv ), end( rv ), low );
+
+			return rv;
+	}
+}
+
+namespace Alepha::Cavorite::inline exports::inline string_algorithms
+{
+	using namespace detail::exports::string_algorithms;
+}