Logtalk built-in method: parameter/2

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## `parameter/2`

#### Description

>     parameter(Number, Term)

> Used only in parametric objects, this method returns parameter values by using the parameter position in the entity identifier. Note that this predicate implies an instantiation between its second argument and the corresponding implicit context argument in the predicate containing the call. This instantiation occurs at the clause head, not at the clause body. See also `this/1`.

#### Template and modes

>     parameter(+integer, ?term)

#### Errors

> Number is a variable:
>   `instantiation_error`
> Number is neither a variable nor an integer value:
>   `type_error(integer, Number)`
> Object identifier is not a compound term:
>   `type_error(compound, Object)`
> Number is a negative integer value:
>   `domain_error(not_less_than_zero, Number)`

#### Examples

>     :- object(box(_Colour)).

>         ...

>         colour(Colour) :-
>             parameter(1, Colour).

>         ...

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