semver.md

id	stdlib-semver
title	SemVer Module
slug	/stdlib/semver

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These core builtins implement SemVer 2.0.0 parsing and precedence. Core numbers and numeric prerelease identifiers cannot have leading zeros. Identifiers use ASCII letters, digits, and hyphens. A leading v, surrounding whitespace, missing components, empty identifiers, and empty -/+ suffixes are rejected. Numeric components remain strings so their size is not limited by the script integer range. Comparisons use numeric precedence for numeric identifiers and ordinal ASCII ordering otherwise; a release sorts after its prereleases. Build metadata is retained when formatting but ignored for precedence.

SemVer.tryParse

None

SemVer.tryParse : string -> ({ Build: string; Major: string; Minor: string; Patch: string; PreRelease: string }) option

Parses a strict SemVer 2.0.0 string into { Major: string; Minor: string; Patch: string; PreRelease: string; Build: string }. Absent prerelease/build components are empty strings. Invalid input returns None.

SemVer.tryParse "1.2.3-rc.1+build" |> Option.map (fun v -> v.Major)
// Some "1"

SemVer.format

None

SemVer.format : { Build: string; Major: string; Minor: string; Patch: string; PreRelease: string } -> string

Formats a parsed or constructed version record. Invalid components raise an error.

SemVer.tryParse "1.2.3-rc.1+build" |> Option.map SemVer.format
// Some "1.2.3-rc.1+build"

SemVer.compare

None

SemVer.compare : string -> string -> int option

Returns Some -1, Some 0, or Some 1 according to SemVer precedence, or None if either input is invalid. Build metadata does not affect precedence.

SemVer.compare "1.0.0-rc.2" "1.0.0-rc.10"
// Some -1