command_line/options: Implemented optionSet_t::displayHelp() with sup…

…port for optional padding

impl/command_line/options.cxx

@@ -139,6 +139,20 @@ namespace substrate::commandLine
 		);
 	}
 
+	void optionSet_t::displayHelp(const size_t padding) const noexcept
+	{
+		console.writeln();
+		// XXX: Need to capitalise the first letter.
+		console.writeln(metaName(), "s:"sv);
+		for (const auto &alternation : _alternations)
+		{
+			console.writeln('\t', alternation.displayName(), nullptr);
+			for ([[maybe_unused]] const auto _ : substrate::indexSequence_t{alternation.displayLength(), padding})
+				console.writeln(' ', nullptr);
+			console.writeln(' ', alternation.helpText());
+		}
+	}
+
 	// Implementation of the innards of optionSet_t as otherwise we get compile errors
 	const optionAlternation_t *optionSet_t::begin() const noexcept
 		{ return _alternations.begin(); }

substrate/command_line/options

@@ -137,7 +137,6 @@ namespace substrate::commandLine
 
 		[[nodiscard]] bool matches(const std::string_view &argument) const noexcept;
 		[[nodiscard]] std::optional<std::any> parseValue(const std::string_view &value) const noexcept;
-		void displayHelp(size_t padding = 0U) const noexcept;
 
 		[[nodiscard]] constexpr bool takesParameter() const noexcept
 			{ return _flags.includes(optionFlags_t::takesParameter); }
@@ -151,6 +150,7 @@ namespace substrate::commandLine
 		[[nodiscard]] std::string_view metaName() const noexcept;
 		[[nodiscard]] std::string displayName() const noexcept;
 		[[nodiscard]] size_t displayLength() const noexcept;
+		void displayHelp(size_t padding = 0U) const noexcept;
 		[[nodiscard]] constexpr auto &helpText() const noexcept { return _help; }
 
 		[[nodiscard]] constexpr bool operator <(const option_t &other) const noexcept
@@ -202,6 +202,7 @@ namespace substrate::commandLine
 		[[nodiscard]] std::optional<std::reference_wrapper<const optionAlternation_t>>
 			matches(const std::string_view &argument) const noexcept;
 		[[nodiscard]] size_t displayPadding() const noexcept;
+		void displayHelp(size_t padding = 0U) const noexcept;
 
 		[[nodiscard]] const optionAlternation_t *begin() const noexcept;
 		[[nodiscard]] const optionAlternation_t *end() const noexcept;