#pragma once #include <iostream> #include <map> #include <memory> #include "util.hh" namespace nix { MakeError(UsageError, Error); enum HashType : char; class Args { public: /* Parse the command line, throwing a UsageError if something goes wrong. */ void parseCmdline(const Strings & cmdline); virtual void printHelp(const string & programName, std::ostream & out); virtual std::string description() { return ""; } protected: /* Flags. */ struct Flag { char shortName; std::string description; Strings labels; size_t arity; std::function<void(Strings)> handler; }; std::map<std::string, Flag> longFlags; std::map<char, Flag> shortFlags; virtual bool processFlag(Strings::iterator & pos, Strings::iterator end); void printFlags(std::ostream & out); /* Positional arguments. */ struct ExpectedArg { std::string label; size_t arity; // 0 = any std::function<void(Strings)> handler; }; std::list<ExpectedArg> expectedArgs; virtual bool processArgs(const Strings & args, bool finish); public: /* Helper functions for constructing flags / positional arguments. */ void mkFlag(char shortName, const std::string & longName, const Strings & labels, const std::string & description, size_t arity, std::function<void(Strings)> handler) { auto flag = Flag{shortName, description, labels, arity, handler}; if (shortName) shortFlags[shortName] = flag; longFlags[longName] = flag; } void mkFlag(char shortName, const std::string & longName, const std::string & description, std::function<void()> fun) { mkFlag(shortName, longName, {}, description, 0, std::bind(fun)); } void mkFlag1(char shortName, const std::string & longName, const std::string & label, const std::string & description, std::function<void(std::string)> fun) { mkFlag(shortName, longName, {label}, description, 1, [=](Strings ss) { fun(ss.front()); }); } void mkFlag(char shortName, const std::string & name, const std::string & description, bool * dest) { mkFlag(shortName, name, description, dest, true); } void mkFlag(char shortName, const std::string & longName, const std::string & label, const std::string & description, string * dest) { mkFlag1(shortName, longName, label, description, [=](std::string s) { *dest = s; }); } void mkHashTypeFlag(const std::string & name, HashType * ht); template<class T> void mkFlag(char shortName, const std::string & longName, const std::string & description, T * dest, const T & value) { mkFlag(shortName, longName, {}, description, 0, [=](Strings ss) { *dest = value; }); } template<class I> void mkIntFlag(char shortName, const std::string & longName, const std::string & description, I * dest) { mkFlag<I>(shortName, longName, description, [=](I n) { *dest = n; }); } template<class I> void mkFlag(char shortName, const std::string & longName, const std::string & description, std::function<void(I)> fun) { mkFlag(shortName, longName, {"N"}, description, 1, [=](Strings ss) { I n; if (!string2Int(ss.front(), n)) throw UsageError(format("flag '--%1%' requires a integer argument") % longName); fun(n); }); } /* Expect a string argument. */ void expectArg(const std::string & label, string * dest) { expectedArgs.push_back(ExpectedArg{label, 1, [=](Strings ss) { *dest = ss.front(); }}); } /* Expect 0 or more arguments. */ void expectArgs(const std::string & label, Strings * dest) { expectedArgs.push_back(ExpectedArg{label, 0, [=](Strings ss) { *dest = ss; }}); } friend class MultiCommand; }; Strings argvToStrings(int argc, char * * argv); /* Helper function for rendering argument labels. */ std::string renderLabels(const Strings & labels); /* Helper function for printing 2-column tables. */ typedef std::vector<std::pair<std::string, std::string>> Table2; void printTable(std::ostream & out, const Table2 & table); }