gonum: add Version query function

doc.go

@@ -0,0 +1,12 @@
+// Copyright ©2019 The Gonum Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Gonum is a set of packages designed to make writing numerical and
+// scientific algorithms productive, performant, and scalable.
+//
+// Gonum contains libraries for matrices and linear algebra; statistics,
+// probability distributions, and sampling; tools for function
+// differentiation, integration, and optimization; network creation and
+// analysis; and more.
+package gonum // import "gonum.org/v1/gonum"

version.go

@@ -0,0 +1,48 @@
+// Copyright ©2019 The Gonum Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build go1.12
+
+package gonum
+
+import (
+	"fmt"
+	"runtime/debug"
+)
+
+const root = "gonum.org/v1/gonum"
+
+// Version returns the version of Gonum and its checksum. The returned
+// values are only valid in binaries built with module support.
+//
+// If a replace directive exists in the Gonum go.mod, the replace will
+// be reported in the version in the following format:
+//  "version=>[replace-path] [replace-version]"
+// and the replace sum will be returned in place of the original sum.
+//
+// The exact version format returned by Version may change in future.
+func Version() (version, sum string) {
+	b, ok := debug.ReadBuildInfo()
+	if !ok {
+		return "", ""
+	}
+	for _, m := range b.Deps {
+		if m.Path == root {
+			if m.Replace != nil {
+				switch {
+				case m.Replace.Version != "" && m.Replace.Path != "":
+					return fmt.Sprintf("%s=>%s %s", m.Version, m.Replace.Path, m.Replace.Version), m.Replace.Sum
+				case m.Replace.Version != "":
+					return fmt.Sprintf("%s=>%s", m.Version, m.Replace.Version), m.Replace.Sum
+				case m.Replace.Path != "":
+					return fmt.Sprintf("%s=>%s", m.Version, m.Replace.Path), m.Replace.Sum
+				default:
+					return m.Version + "*", m.Sum + "*"
+				}
+			}
+			return m.Version, m.Sum
+		}
+	}
+	return "", ""
+}