either — Logtalk APIs v3.47.0 documentation

object

# `either`

Types and predicates for extended type-checking and handling of expected terms.

Author: Paulo Moura
Version: 0:7:0
Date: 2021-01-03
Compilation flags:
`static, context_switching_calls`
Provides:
type::type/1
type::check/2
arbitrary::arbitrary/1
arbitrary::arbitrary/2
Uses:
expected
expected(Expected)
random
type
Remarks:

> - Type-checking support: Defines a `either(ValueType, ErrorType)` type for checking expected terms where the value and error terms must be of the given types.

> - QuickCheck support: Defines clauses for the `type::arbitrary/1-2` predicates to allow generating random values for the `either(ValueType, ErrorType)` type.

Inherited public predicates:
(none)

- Public predicates

  - `expecteds/2`

  - `unexpecteds/2`

  - `partition/3`

- Protected predicates

- Private predicates

- Operators

## Public predicates

### `expecteds/2`

Returns the values stored in the expected terms that hold a value.

Compilation flags:
`static`
Template:
`expecteds(Expecteds,Values)`
Mode and number of proofs:
`expecteds(+list(expected),-list)` - `one`

### `unexpecteds/2`

Returns the errors stored in the expected terms that hold an error.

Compilation flags:
`static`
Template:
`unexpecteds(Expecteds,Errors)`
Mode and number of proofs:
`unexpecteds(+list(expected),-list)` - `one`

### `partition/3`

Retrieves and partitions the values and errors hold by the expected terms.

Compilation flags:
`static`
Template:
`partition(Expecteds,Values,Errors)`
Mode and number of proofs:
`partition(+list(expected),-list,-list)` - `one`

## Protected predicates

(no local declarations; see entity ancestors if any)

## Private predicates

(no local declarations; see entity ancestors if any)

## Operators

(none)

See also

expected, expected(Expected), type, arbitrary