The flags from sailormoon

flags's Issues

Argument validation + shortcuts

Now that there are some basic unit tests, flag validation and multiple arguments should be added.

Currently thinking of a syntax similar to:

const flags::args args(argc, argv);
if (const auto opt = args.get_multiple<bool>("flag", "f", "no-flag", "other")) {
  const auto [argument, value] = *opt;
  // do something -- *argument will be the first of "flag", "f", or "no-flag" that matched
  // and *value will be its value.
}

for multiple arguments.

Remove `using std::experimental::{optional, nullopt, string_view}` from flags namespace.

Out of laziness, and because std::experimental is such a long namespace, using std::experimental::{optional, nullopt, string_view} was used in the flags namespace. It should be removed when when both optional and string_view are moved into std proper.

Boolean options return false if no value was specified in the command line

Steps to reproduce:

Copy the example to a file named src.cpp

#include "flags.h"
#include <iostream>

int main(int argc, char** argv) {
  const flags::args args(argc, argv);

  const auto count = args.get<int>("count");
  if (!count) {
    std::cerr << "No count supplied. :(\n";
    return 1;
  }
  std::cout << "That's " << *count << " incredible, colossal credits!\n";

  if (args.get<bool>("laugh", false)) {
    std::cout << "Ha ha ha ha!\n";
  }
  return 0;
}

Add flags.h to the same folder.
Compile using clang src.cpp -std=c++17 -o program.exe
Run using .\program.exe --count 5 --laugh

Expected result:

That's 5 incredible, colossal credits!
Ha ha ha ha!

Actual result:

That's 5 incredible, colossal credits!

Environment:

OS: Windows 10
Compiler: Clang 9.0.0

Reason behind the issue:

template <>
std::optional<bool> get(const argument_map& options,
                        const std::string_view& option) {
  if (const auto value = get_value(options, option)) {
    return std::none_of(falsities.begin(), falsities.end(),
                        [&value](auto falsity) { return *value == falsity; });
  }
  return std::nullopt;
}

In the aforementioned code, the function cannot differentiate between the two scenarios:

.\program.exe --count 5 --laugh
.\program.exe --count 5

Since in both cases, args.get<bool>("laugh") will return std::nullopt.

Suggested fix:
Check if the option exists in the options map.

template <>
std::optional<bool> get(const argument_map& options,
                        const std::string_view& option) {
  if (const auto value = get_value(options, option)) {
    return std::none_of(falsities.begin(), falsities.end(),
                        [&value](auto falsity) { return *value == falsity; });
  }
  if (options.find(option) != options.end())
      return true;
  return std::nullopt;
}

Unit tests and Travis CI

Unit tests should be written using https://github.com/jimporter/mettle.
There should be a Travis CI build/test ticker in the README after tests are added.

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flags's Issues

Argument validation + shortcuts

Remove `using std::experimental::{optional, nullopt, string_view}` from flags namespace.

Boolean options return false if no value was specified in the command line

Unit tests and Travis CI

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