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#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);
virtual 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);
}
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