Utilities to check if a lens verifies the lens laws.

This module is meant to be used in test suites.

IdentitySpec[S] = tuple[expected: S]: Parameters for the lens identity law. Source Edit
RetentionSpec[S; T] = tuple[input: S, expected: T]: Parameters for the lens retention law. Source Edit
DoubleWriteSpec[S; T] = tuple[input: S, first: T, second: T]: Parameters for the lens double write law. Source Edit
LensLawsSpec[S; T] = tuple[identity: IdentitySpec[S], retention: RetentionSpec[S, T], doubleWrite: DoubleWriteSpec[S, T]]: Source Edit

Funcs

func identitySpec[S](expected: S): IdentitySpec[S]: Source Edit
func retentionSpec[S; T](input: S; expected: T): RetentionSpec[S, T]: Source Edit
func doubleWriteSpec[S; T](input: S; first: T; second: T): DoubleWriteSpec[S, T]: Source Edit
func lensLawsSpec[S; T](identity: IdentitySpec[S]; retention: RetentionSpec[S, T]; doubleWrite: DoubleWriteSpec[S, T]): LensLawsSpec[S, T]: Source Edit

Templates

template checkIdentityLaw[S; T](lens: Lens[S, T]; spec: IdentitySpec[S]): bool: Checks whether a read followed by a write through lens is the same as not modifying the initial structure. Source Edit
template checkRetentionLaw[S; T](lens: Lens[S, T]; spec: RetentionSpec[S, T]): bool: Checks whether a write followed by a read through lens returns the same value written. Source Edit
template checkDoubleWriteLaw[S; T](lens: Lens[S, T]; spec: DoubleWriteSpec[S, T]): bool: Checks whether two consecutive writes through lens is the same as directly writing the second value. Source Edit
template checkLensLaws[S; T](lens: Lens[S, T]; spec: LensLawsSpec[S, T]): bool: Source Edit