add version package

version.go

@@ -0,0 +1,59 @@
+package version
+
+import (
+	"fmt"
+)
+
+// Version is a structured representation of a version number
+type Version struct {
+	Major     int
+	Minor     int
+	Patch     int
+	Extension string
+
+	Text string
+}
+
+// Compare this version (a) with another version (b).
+// This function returns -1 if a is less than b, 1 if a is greater than b, or 0 if a is equal to b.
+//
+// Extensions such as pre-release version or build metadata are ignored when comparing versions.
+func (a *Version) Compare(b *Version) int {
+	if a.Major == b.Major {
+		if a.Minor == b.Minor {
+			if a.Patch == b.Patch {
+				return 0
+			} else if a.Patch > b.Patch {
+				return 1
+			}
+		} else if a.Minor > b.Minor {
+			return 1
+		}
+	} else if a.Major > b.Major {
+		return 1
+	}
+
+	return -1
+}
+
+// Less performs a simple comparison of this version (a) with another version (b).
+// This function returns true if a is less than b, or false otherwise.
+//
+// Extensions such as pre-release version or build metadata are ignored when comparing versions.
+func (a *Version) Less(b *Version) bool {
+	return a.Compare(b) < 0
+}
+
+// SemanticString returns a version string conforming to the standard described in Semantic Versioning 2.0.0.
+//
+// See https://semver.org/#is-v123-a-semantic-version
+func (v *Version) SemanticString() string {
+	return fmt.Sprintf("%d.%d.%d%s", v.Major, v.Minor, v.Patch, v.Extension)
+}
+
+func (v *Version) String() string {
+	if v.Text != "" {
+		return v.Text
+	}
+	return v.SemanticString()
+}