(std clr-ord)

Provides Ord instances for common .NET types: DateTime, TimeSpan, DateOnly, TimeOnly, Guid, and Version.

(import (std prelude))
(import (std clr-ord))

;; An alias with a constructor. The Ord instance applies because it
;; refers to the underlying .NET type.
(import/class
  (Date (: System.DateTime (-> int int int Date))))

(list-sort (list (Date. 2021 1 1) (Date. 2019 6 5)))   ; 2019 first
(less? (Date. 2019 1 1) (Date. 2020 1 1))              ; #t

Import this module to sort and compare these .NET types using compare, less?, list-sort, and ordered collections. Each Ord implementation delegates to the type’s CompareTo method. Equality is handled by default Eq, which delegates to Equals.

Supported types include System.DateTime, System.DateTimeOffset, System.TimeSpan, System.DateOnly, System.TimeOnly, System.Guid, and System.Version.

Exported aliases. Only Guid and Version are exported as named aliases to avoid collisions with (std datetime). To use the other .NET time types, reference their full names (such as System.DateTime) or declare a local alias via import/class. The Ord implementations apply to the underlying .NET type regardless of alias. The exported aliases do not provide constructors; define a local alias with a constructor if you need to instantiate values directly.

Ordering follows .NET semantics: DateTime compares ticks and ignores Kind, while DateTimeOffset compares timestamps in UTC.

See also: Guid, Version

(import/class
  (Ver (: System.Version (-> int int int Ver))))

(less? (Ver. 1 9 0) (Ver. 1 10 0))   ; #t: compared numerically, not lexically