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◆ main openmsx / src / commands / TclArgParser.hh
3.2 KiB · C++ · last changed chore(): initial commit 1 month ago source blame history raw
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#ifndef TCLARGPARSER_HH
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#define TCLARGPARSER_HH
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#include "CommandException.hh"
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#include "TclObject.hh"
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#include <functional>
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#include <optional>
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#include <span>
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#include <string_view>
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#include <vector>
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namespace openmsx {
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namespace detail {
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	template<typename T> struct GetArg;
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	template<> struct GetArg<bool> {
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		void operator()(Interpreter& interp, const TclObject& obj, bool& result) const {
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			result = obj.getBoolean(interp);
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		}
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	};
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	template<> struct GetArg<int> {
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		void operator()(Interpreter& interp, const TclObject& obj, int& result) const {
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			result = obj.getInt(interp);
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		}
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	};
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	template<> struct GetArg<double> {
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		void operator()(Interpreter& interp, const TclObject& obj, double& result) const {
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			result = obj.getDouble(interp);
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		}
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	};
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	template<> struct GetArg<std::string_view> {
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		void operator()(Interpreter& /*interp*/, const TclObject& obj, std::string_view& result) const {
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			result = obj.getString();
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		}
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	};
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	template<> struct GetArg<std::string> {
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		void operator()(Interpreter& /*interp*/, const TclObject& obj, std::string& result) const {
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			result = std::string(obj.getString());
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		}
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	};
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	template<> struct GetArg<TclObject> {
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		void operator()(Interpreter& /*interp*/, const TclObject& obj, TclObject& result) const {
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			result = obj;
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		}
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	};
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	template<typename T> struct GetArg<std::optional<T>> {
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		void operator()(Interpreter& interp, const TclObject& obj, std::optional<T>& result) const {
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			T t;
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			GetArg<T>{}(interp, obj, t);
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			result = std::move(t);
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		}
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	};
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	template<typename T> struct GetArg<std::vector<T>> {
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		void operator()(Interpreter& interp, const TclObject& obj, std::vector<T>& result) const {
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			result.emplace_back();
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			GetArg<T>{}(interp, obj, result.back());
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		}
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	};
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}
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// A Tcl-argument-parser description is made out of ArgsInfo objects
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struct ArgsInfo
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{
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	std::string_view name;
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	std::function<unsigned(Interpreter&, std::span<const TclObject>)> func;
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};
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// Parse a flag.
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[[nodiscard]] inline ArgsInfo flagArg(std::string_view name, bool& flag)
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{
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	return {
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		.name = name,
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		.func = [&flag](Interpreter& /*interp*/, std::span<const TclObject> /*args*/) {
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			flag = true;
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			return 0;
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		}
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	};
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}
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// Option with a single value, handled by a callback
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[[nodiscard]] inline ArgsInfo funcArg(
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	std::string_view name,
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	std::function<void(Interpreter&, const TclObject&)> func)
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{
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	return {
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		.name = name,
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		.func = [name, func = std::move(func)](Interpreter& interp, std::span<const TclObject> args) {
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			if (args.empty()) {
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				throw CommandException("missing argument for ", name);
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			}
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			func(interp, args.front());
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			return 1;
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		}
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	};
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}
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// Parse a value (like a flag but with associated value).
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template<typename T>
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[[nodiscard]] ArgsInfo valueArg(std::string_view name, T& value)
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{
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	return funcArg(name, [&value](Interpreter& interp, const TclObject& arg) {
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		detail::GetArg<T>{}(interp, arg, value);
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	});
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}
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// Parse the given 'inArgs' arguments.
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// The recognized flags/values are described in 'table'.
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// The result of this parser is the collection of non-flag arguments.
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// See src/unittest/TclArgParser.cc for example usages.
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[[nodiscard]] std::vector<TclObject> parseTclArgs(
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	Interpreter& interp, std::span<const TclObject> inArgs, std::span<const ArgsInfo> table);
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} // namespace openmsx
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#endif