SWI-Prolog -- option/3

Documentation
- Reference manual
  - The SWI-Prolog library
    - library(option): Option list processing
- Packages

Availability::- use_module(library(option)).(can be autoloaded)

[det]option(?Option, +Options, +Default)

Get an Option from Options. If Option does not appear in Options, unify the value with Default. If Option appears multiple times in Options, the first value is used. For example

?- option(max_depth(D), [x(a), max_depth(20)], 10).
D = 20.
?- option(max_depth(D), [x(a)], 10).
D = 10.

`Option`	Term of the form Name(?Value).
`Options`	is a list of Name(Value) or `Name=Value` or a dict.