object

`either`

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

Availability:

logtalk_load(expecteds(loader))

Author: Paulo Moura
Version: 0:9:0
Date: 2025-06-19

Compilation flags:

static, context_switching_calls

Provides:

type::type/1
type::check/2
arbitrary::arbitrary/1
arbitrary::arbitrary/2
arbitrary::shrinker/1
arbitrary::shrink/3
arbitrary::edge_case/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, arbitrary::shrinker/1, arbitrary::shrink/3, and arbitrary::edge_case/2 predicates to allow generating random values for the either(ValueType, ErrorType) type.

Inherited public predicates:

(none)

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

`sequence/2`

Returns an expected term with a list of all values when all expected terms hold values. Otherwise returns the first expected term holding an error.

Compilation flags:

static

Template:

sequence(Expecteds,Expected)

Mode and number of proofs:

sequence(+list(expected),--nonvar) - one

`traverse/3`

Applies a closure to each list element to generate expected terms and then sequences them into a single expected term holding all values or the first error.

Compilation flags:

static

Template:

traverse(Closure,Terms,Expected)

Meta-predicate template:

traverse(2,*,*)

Mode and number of proofs:

traverse(+callable,+list,--nonvar) - one

Protected predicates 

(no local declarations; see entity ancestors if any)

Private predicates 

(no local declarations; see entity ancestors if any)

Operators 

(none)

either

`either`