Syntax Description

A command line as understood by Argum can contain:

• Any number of Options
• Any number of Positional Arguments or simply Positionals
• An optional single Option Terminator. If an Option Terminator occurs everything following it is considered a Positional.

In BNF notation

CommandLine := *(*Option *Positional) [OptionTerminator *AnyArgument]

Options

An Option can be of one of the three types described below. All option types allow a single optional Argument to be given with them.

Short Options

A standalone short option starts with one of the defined short option prefixes followed by a single letter. By default the only short option prefix is - but that can be changed. If no short option prefixes are configured the short options aren't recognized.

Thus -a is a short option and so is -c. However -foo isn't (more than one letter) and so isn't --c (wrong prefix).

A short option can have an argument either as a separate command line argument either:

• directly following it: -c arg or
• attached to it: -carg. In both cases the Argument is arg.

Multiple consequent short options can be concatenated together with one prefix. For example if -c and -a are both short options they can be specified:

• separately as -c -a or
• merged as -ca

If short options are merged only the last one of the merged sequence can have an argument. Both

• -ca arg and
• -caarg mean option -c followed by -a with an argument arg

Multi-short options

A multi-short option starts with one of the defined short option prefixes followed by more than one letter. By default the only short option prefix is - but that can be changed. If no short option prefixes are configured the multi-short options aren't recognized.

Thus -foo is a multi-short option and so is -bar.

By default, multi-short options can be abbreviated so if a -foo option is defined, -fo and -f will be recognized as -foo as well. Such abbreviation can be disabled.

Resolving ambiguities between multi-short and short options

Due to definitions above various ambiguities can arise. For example if -bar, -baz and -b are all defined then -ba is potentially ambiguous and so is -b. Moreover if -a and -r are also defined in addition to those then does -bar mean -bar or merged -b, -a and -r? Argum resolves any ambiguities in the following manner: