cmdline: A simple command line parser for C++

About

This is a simple command line parser for C++.

• Easy to use
• Only one header file
• Automatic type check

Sample

Here show sample usages of cmdline.

Normal usage

This is an example of simple usage.

// include cmdline.h
#include "cmdline.h"

int main(int argc, char *argv[])
{
  // create a parser
  cmdline::parser a;

  // add specified type of variable.
  // 1st argument is long name
  // 2nd argument is short name (no short name if '\0' specified)
  // 3rd argument is description
  // 4th argument is mandatory (optional. default is false)
  // 5th argument is default value  (optional. it used when mandatory is false)
  a.add<string>("host", 'h', "host name", true, "");

  // 6th argument is extra constraint.
  // Here, port number must be 1 to 65535 by cmdline::range().
  a.add<int>("port", 'p', "port number", false, 80, cmdline::range(1, 65535));

  // cmdline::oneof() can restrict options.
  a.add<string>("type", 't', "protocol type", false, "http", cmdline::oneof<string>("http", "https", "ssh", "ftp"));

  // Boolean flags also can be defined.
  // Call add method without a type parameter.
  a.add("gzip", '\0', "gzip when transfer");

  // Run parser.
  // It returns only if command line arguments are valid.
  // If arguments are invalid, a parser output error msgs then exit program.
  // If help flag ('--help' or '-?') is specified, a parser output usage message then exit program.
  a.parse_run(argc, argv);

  // use flag values
  cout << a.get<string>("type") << "://"
       << a.get<string>("host") << ":"
       << a.get<int>("port") << endl;

  // boolean flags are referred by calling exist() method.
  if (a.exist("gzip")) cout << "gzip" << endl;
}

Here are some execution results:

$ ./test
usage: ./test --host=string [options] ... 
options:
  -h, --host    host name (string)
  -p, --port    port number (int [=80])
  -t, --type    protocol type (string [=http])
      --gzip    gzip when transfer
  -?, --help    print this message

$ ./test -?
usage: ./test --host=string [options] ... 
options:
  -h, --host    host name (string)
  -p, --port    port number (int [=80])
  -t, --type    protocol type (string [=http])
     --gzip    gzip when transfer
  -?, --help    print this message

$ ./test --host=github.com
http://github.com:80

$ ./test --host=github.com -t ftp
ftp://github.com:80

$ ./test --host=github.com -t ttp
option value is invalid: --type=ttp
usage: ./test --host=string [options] ... 
options:
  -h, --host    host name (string)
  -p, --port    port number (int [=80])
  -t, --type    protocol type (string [=http])
      --gzip    gzip when transfer
  -?, --help    print this message

$ ./test --host=github.com -p 4545
http://github.com:4545

$ ./test --host=github.com -p 100000
option value is invalid: --port=100000
usage: ./test --host=string [options] ... 
options:
  -h, --host    host name (string)
  -p, --port    port number (int [=80])
  -t, --type    protocol type (string [=http])
      --gzip    gzip when transfer
  -?, --help    print this message

$ ./test --host=github.com --gzip
http://github.com:80
gzip

Extra Options

• rest of arguments

Rest of arguments are referenced by rest() method. It returns vector of string. Usualy, they are used to specify filenames, and so on.

for (int i = 0; i < a.rest().size(); i++)
  cout << a.rest()[i] << endl\;

• footer

footer() method is add a footer text of usage.

...
a.footer("filename ...");
...

Result is:

$ ./test
usage: ./test --host=string [options] ... filename ...
options:
  -h, --host    host name (string)
  -p, --port    port number (int [=80])
  -t, --type    protocol type (string [=http])
      --gzip    gzip when transfer
  -?, --help    print this message

• program name

A parser shows program name to usage message. Default program name is determin by argv[0]. set_program_name() method can set any string to program name.

(For more information, you may read test2.cpp.)