Global parameters

Programs often differ only in the values of some constants, with the overall structure of the rules remaining the same. Global parameters make this explicit and allow reusing a program where just these values change.

A global parameter is declared using @parameter, as follows:

@parameter $name .

Afterwards, $name can be used throughout the program (in rules and in facts) like any constant. Optionally, a default value can be given:

@parameter $with_default = <https://example.org/default> .

Values for parameters can be specified on the command line with the --param option, as follows:

nmo rules.rls --param "name=<https://example.org/name>" .