#### 11.3.242 `=../2`

*ISO*

#### Synopsis

`+Term` `=..`

`-List`

`-Term` `=..`

`+List`

Unifies `List` with a list whose head is the atom corresponding
to the principal functor of `Term` and whose tail is a list of
the arguments of `Term`.

#### Arguments

`Term`
*term*
any term

`List`
*list of term*
and not empty

#### Description

If `Term` is uninstantiated, then `List` must be instantiated
either to a proper list whose head is an atom, or to a list of length
1 whose head is a number.

This predicate is not strictly necessary, since its functionality can
be provided by `arg/3`

and `functor/3`

, and using the latter
two is usually more efficient.

#### Examples

| ?- `product(0, n, n-1) =.. L.`
L = [product,0,n,n-1]
| ?- `n-1 =.. L.`
L = [-,n,1]
| ?- `product =.. L.`
L = [product]

#### Exceptions

`instantiation_error`

`Term` is unbound and `List` is not instantiated enough.

`type_error`

`List` is not a proper list, or
the head of `List` is not atomic, or
the head of `List` is a number and the tail of `List` is not empty.

`domain_error`

`List` is the empty list.

`representation_error`

`Term` is uninstantiated and `List` is longer than 256.

#### See Also

`functor/3`

, `arg/3`

, ref-lte-act.

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