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Diffstat (limited to 'third-party/cxxopts/README.md')
| -rw-r--r-- | third-party/cxxopts/README.md | 46 |
1 files changed, 35 insertions, 11 deletions
diff --git a/third-party/cxxopts/README.md b/third-party/cxxopts/README.md index 9517993d04..de69e5ab88 100644 --- a/third-party/cxxopts/README.md +++ b/third-party/cxxopts/README.md @@ -7,9 +7,9 @@ tagged release version. ## Version 3 breaking changes -If you have used version 2, there are a couple of breaking changes in (the as -yet unreleased, current master) version 3 that you should be aware of. If you are new to -`cxxopts` you can skip this section. +If you have used version 2, there are a couple of breaking changes in version 3 +that you should be aware of. If you are new to `cxxopts` you can skip this +section. The parser no longer modifies its arguments, so you can pass a const `argc` and `argv` and expect them not to be changed. @@ -109,9 +109,9 @@ result.unmatched() Exceptional situations throw C++ exceptions. There are two types of exceptions: errors defining the options, and errors when parsing a list of -arguments. All exceptions derive from `cxxopts::OptionException`. Errors -defining options derive from `cxxopts::OptionSpecException` and errors -parsing arguments derive from `cxxopts::OptionParseException`. +arguments. All exceptions derive from `cxxopts::exceptions::exception`. Errors +defining options derive from `cxxopts::exceptions::specification` and errors +parsing arguments derive from `cxxopts::exceptions::parsing`. All exceptions define a `what()` function to get a printable string explaining the error. @@ -125,15 +125,37 @@ vector to the `help` function. ## Positional Arguments -Positional arguments can be optionally parsed into one or more options. -To set up positional arguments, call +Positional arguments are those given without a preceding flag and can be used +alongside non-positional arguments. There may be multiple positional arguments, +and the final positional argument may be a container type to hold a list of all +remaining positionals. + +To set up positional arguments, first declare the options, then configure a +set of those arguments as positional like: ```cpp -options.parse_positional({"first", "second", "last"}) +options.add_options() + ("script", "The script file to execute", cxxopts::value<std::string>()) + ("server", "The server to execute on", cxxopts::value<std::string>()) + ("filenames", "The filename(s) to process", cxxopts::value<std::vector<std::string>>()); + +options.parse_positional({"script", "server", "filenames"}); + +// Parse options the usual way +options.parse(argc, argv); ``` -where "last" should be the name of an option with a container type, and the -others should have a single value. +For example, parsing the following arguments: +~~~ +my_script.py my_server.com file1.txt file2.txt file3.txt +~~~ +will result in parsed arguments like the following table: + +| Field | Value | +| ------------- | ----------------------------------------- | +| `"script"` | `"my_script.py"` | +| `"server"` | `"my_server.com"` | +| `"filenames"` | `{"file1.txt", "file2.txt", "file3.txt"}` | ## Default and implicit values @@ -161,6 +183,8 @@ Note that the default and implicit value is always stored as a string, regardless of the type that you want to store it in. It will be parsed as though it was given on the command line. +Default values are not counted by `Options::count`. + ## Boolean values Boolean options have a default implicit value of `"true"`, which can be |