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flags-cpp
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macro and basic parsers

This commit is contained in:
Benedek László 2023-12-01 03:32:03 +01:00
parent e1588bcd70
commit 37a397d3e6
2 changed files with 140 additions and 37 deletions
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120
flags.cpp
View File

@ -1,5 +1,6 @@
#include "flags.h"
#include <sstream>
#include <iostream>
namespace Flags {
@ -14,7 +15,110 @@ std::vector<std::string> split(const std::string &input, const char separator) {
}
bool starts_with(const std::string &input, const std::string &start) {
return (input.length() >= start.length() && input.substr(0, 2) == start);
return (input.size() >= start.size() && input.substr(0, 2) == start);
}
PARSER(StringFlag, std::string, {
set_found(true);
set_parsed(true);
value = arg;
})
PARSER(IntFlag, int, {
set_found(true);
try {
value = std::stoi(arg);
set_parsed(true);
} catch (std::exception &) {
}
})
PARSER(LongIntFlag, long int, {
set_found(true);
try {
value = std::stol(arg);
set_parsed(true);
} catch (std::exception &) {
}
})
PARSER(LongLongIntFlag, long long int, {
set_found(true);
try {
value = std::stoll(arg);
set_parsed(true);
} catch (std::exception &) {
}
})
PARSER(UnsignedLongIntFlag, unsigned long int, {
set_found(true);
try {
value = std::stoul(arg);
set_parsed(true);
} catch (std::exception &) {
}
})
PARSER(UnsignedLongLongIntFlag, unsigned long long int, {
set_found(true);
try {
value = std::stoull(arg);
set_parsed(true);
} catch (std::exception &) {
}
})
PARSER(FloatFlag, float, {
set_found(true);
try {
value = std::stof(arg);
set_parsed(true);
} catch (std::exception &) {
}
})
PARSER(DoubleFlag, double, {
set_found(true);
try {
value = stod(arg);
set_parsed(true);
} catch (std::exception &) {
}
})
PARSER(LongDoubleFlag, long double, {
set_found(true);
try {
value = stold(arg);
set_parsed(true);
} catch (std::exception &) {
}
})
PARSER(BoolFlag, bool, {
std::string copy(arg);
std::transform(copy.begin(), copy.end(), copy.begin(),
[](const char c) { return std::tolower(c); });
if (copy == "false")
value = false;
else
value = true;
})
Parser::Parser(const std::string &prefix, const std::string &help_text)
: prefix(prefix), help_text(help_text) {
set_parser<std::string>(flag_constructor_t(StringFlag::make));
set_parser<int>(flag_constructor_t(IntFlag::make));
set_parser<long int>(flag_constructor_t(LongIntFlag::make));
set_parser<long long int>(flag_constructor_t(LongLongIntFlag::make));
set_parser<unsigned long int>(flag_constructor_t(UnsignedLongIntFlag::make));
set_parser<unsigned long long int>(
flag_constructor_t(UnsignedLongLongIntFlag::make));
set_parser<float>(flag_constructor_t(FloatFlag::make));
set_parser<double>(flag_constructor_t(DoubleFlag::make));
set_parser<long double>(flag_constructor_t(LongDoubleFlag::make));
set_parser<bool>(flag_constructor_t(BoolFlag::make));
}
bool Parser::parse(int argc, char **argv) {
@ -22,7 +126,7 @@ bool Parser::parse(int argc, char **argv) {
std::vector<std::string> args;
for (int i = 0; i < argc; i++) {
std::string arg(argv[i]);
if (starts_with(arg, prefix) && arg.length() > prefix.length()) {
if (starts_with(arg, prefix) && arg.size() > prefix.size()) {
std::vector<std::string> parts = split(arg, '=');
args.insert(args.end(), parts.begin(), parts.end());
} else {
@ -33,27 +137,27 @@ bool Parser::parse(int argc, char **argv) {
// search for flags
for (size_t i = 1; i < args.size() - 1; i++) {
const std::string &arg = args[i];
if (starts_with(arg, prefix) && arg.length() > prefix.length()) {
flags[arg.substr(prefix.length())]->parse(args[i + 1]);
if (starts_with(arg, prefix) && arg.size() > prefix.size()) {
flags[arg.substr(prefix.size())]->parse(args[i + 1]);
}
}
// check for the last argument
if (starts_with(args[args.size() - 1], prefix) &&
args[args.size() - 1].length() > prefix.length()) {
flags[args[args.size() - 1].substr(prefix.length())]->parse("");
args[args.size() - 1].size() > prefix.size()) {
flags[args[args.size() - 1].substr(prefix.size())]->parse("");
}
return get_found() == flags.size();
}
const unsigned Parser::get_parsed() const {
unsigned Parser::get_parsed() const {
return std::count_if(
flags.begin(), flags.end(),
[](std::pair<std::string, Flag *> f) { return f.second->get_parsed(); });
}
const unsigned Parser::get_found() const {
unsigned Parser::get_found() const {
return std::count_if(
flags.begin(), flags.end(),
[](std::pair<std::string, Flag *> f) { return f.second->get_found(); });

55
flags.h
View File

@ -1,9 +1,7 @@
#ifndef FLAGS_H
#define FLAGS_H
#include <algorithm>
#include <functional>
#include <iostream>
#include <map>
#include <string>
#include <typeindex>
@ -34,38 +32,41 @@ public:
virtual ~Flag(){};
const std::string &get_description() const { return description; }
const bool get_found() const { return found; }
const bool get_parsed() const { return parsed; }
bool get_found() const { return found; }
bool get_parsed() const { return parsed; }
virtual void parse(const std::string &arg) {}
virtual void parse(const std::string &arg) = 0;
};
// type of flag based parser classes' factory functions
typedef std::function<Flag *(const void *, const std::string &, const bool)>
flag_constructor_t;
class StringFlag : public Flag {
std::string value;
// use this class to create your own parser
template <typename T> class FlagTemplate : public Flag {
protected:
T value;
public:
StringFlag(const void *default_value, const std::string &description,
const bool required)
: Flag(description, required), value(*(std::string *)default_value) {}
static Flag *make(const void *default_value, const std::string &description,
const bool required) {
return new StringFlag(default_value, description, required);
}
explicit FlagTemplate<T>(const void *default_value,
const std::string &description, const bool required)
: Flag(description, required), value(*(T *)default_value) {}
const void *get_value_ptr() const override { return &value; };
void parse(const std::string &arg) override {
set_found(true);
set_parsed(true);
value = arg;
}
};
#define PARSER(name, type, func) \
class name : public FlagTemplate<type> { \
using FlagTemplate<type>::FlagTemplate; \
\
public: \
static Flag *make(const void *default_value, \
const std::string &description, const bool required) { \
return new name(default_value, description, required); \
} \
void parse(const std::string &arg) override func \
}; // namespace Flags
// flag holder, parsing orchestrator
class Parser {
private:
@ -76,10 +77,7 @@ private:
std::map<std::type_index, flag_constructor_t> constructors;
public:
Parser(const std::string &prefix, const std::string &help_text)
: prefix(prefix), help_text(help_text) {
set_parser<std::string>(flag_constructor_t(StringFlag::make));
}
Parser(const std::string &prefix, const std::string &help_text);
Parser() : Parser("--", "Help:") {}
@ -89,7 +87,8 @@ public:
}
}
template <typename T> void set_parser(flag_constructor_t constructor_function) {
template <typename T>
void set_parser(flag_constructor_t constructor_function) {
constructors[typeid(T)] = constructor_function;
}
@ -101,9 +100,9 @@ public:
return (T *)flags[name]->get_value_ptr();
}
const unsigned get_found() const;
unsigned get_found() const;
const unsigned get_parsed() const;
unsigned get_parsed() const;
bool parse(int argc, char **argv);