d7b930846c
* Prevent malformed numbers from being parsed as correct numbers. Fixes #78. If you passed a string for example "test" it would get parsed to 1400. The problem was that the parser did not throw an exception when an incorrect char was encountered. Also a number without 0x in front with hexadecimal digits in it got parsed. The number was treated as a hexadecimal number but it was still calculated with base 10. So now before the current char is used, it is checked if it is valid in the current base. Furthermore the number 0x0 was not a valid number, it now is a special case in the `integer_pattern`. * Fixed `integer_pattern` so it works correctly under clang. Added testcase for invalid integers and for 0x0 being a valid number. |
||
---|---|---|
include | ||
src | ||
test | ||
.gitignore | ||
.travis.yml | ||
CMakeLists.txt | ||
cxxopts-config.cmake.in | ||
INSTALL | ||
LICENSE | ||
README.md |
Quick start
This is a lightweight C++ option parser library, supporting the standard GNU style syntax for options.
Options can be given as:
--long
--long=argument
--long argument
-a
-ab
-abc argument
where c takes an argument, but a and b do not.
Additionally, anything after --
will be parsed as a positional argument.
Basics
#include <cxxopts.hpp>
Create a cxxopts::Options instance.
cxxopts::Options options("MyProgram", "One line description of MyProgram");
Then use add_options
.
options.add_options()
("d,debug", "Enable debugging")
("f,file", "File name", cxxopts::value<std::string>())
;
Options are declared with a long and an optional short option. A description must be provided. The third argument is the value, if omitted it is boolean. Any type can be given as long as it can be parsed, with operator>>.
To parse the command line do:
options.parse(argc, argv);
To retrieve an option use options.count("option")
to get the number of times
it appeared, and
options["opt"].as<type>()
to get its value. If "opt" doesn't exist, or isn't of the right type, then an exception will be thrown.
Help groups
Options can be placed into groups for the purposes of displaying help messages.
To place options in a group, pass the group as a string to add_options
. Then,
when displaying the help, pass the groups that you would like displayed as a
vector to the help
function.
Positional Arguments
Positional arguments can be optionally parsed into one or more options. To set up positional arguments, call
options.parse_positional({"first", "second", "last"})
where "last" should be the name of an option with a container type, and the others should have a single value.
Default and implicit values
An option can be declared with a default or an implicit value, or both.
A default value is the value that an option takes when it is not specified on the command line. The following specifies a default value for an option:
cxxopts::value<std::string>()->default_value("value")
An implicit value is the value that an option takes when it is given on the command line without an argument. The following specifies an implicit value:
cxxopts::value<std::string>()->implicit_value("implicit")
If an option had both, then not specifying it would give the value "value"
,
writing it on the command line as --option
would give the value "implicit"
,
and writing --option=another
would give it the value "another"
.
Linking
This is a header only library.
Requirements
The only build requirement is a C++ compiler that supports C++11 regular expressions. For example GCC >= 4.9 or clang with libc++.
TODO list
- Allow unrecognised options.
- Various help strings.
- Unicode aware for help strings.