The library(option) provides some utilities for 
processing option lists. Option lists are commonly used as an 
alternative for many arguments. Examples of built-in predicates are open/4 
and write_term/3. 
Naming the arguments results in more readable code, and the list nature 
makes it easy to extend the list of options accepted by a predicate. 
Option lists come in two styles, both of which are handled by this 
library.
Processing options inside time-critical code (loops) can cause 
serious overhead. One possibility is to define a record using library(record) 
and initialise this using make_<record>/2. 
In addition to providing good performance, this also provides 
type-checking and central declaration of defaults.
:- record atts(width:integer=100, shape:oneof([box,circle])=box).
process(Data, Options) :-
        make_atts(Options, Attributes),
        action(Data, Attributes).
action(Data, Attributes) :-
        atts_shape(Attributes, Shape),
        ...
Options typically have exactly one argument. The library does support options with 0 or more than one argument with the following restrictions:
arg(1, Option, Default), 
causing failure without arguments and filling only the first 
option-argument otherwise.
| Option | Term of the form Name(?Value). | 
| Option | Term of the form Name(?Value). | 
Multi-values options (e.g., proxy(Host, Port)) are 
allowed, where both option-name and arity define the identity of the 
option.
call(IsMeta, Name). 
Here is an example:
        meta_options(is_meta, OptionsIn, Options),
        ...
is_meta(callback).
Meta-options must have exactly one argument. This argument will be qualified.
name(V1,V2)). 
This is not allowed in dicts.
Also note that most system predicates and predicates using this library for processing the option argument can both work with classical Prolog options and dicts objects.