commit 741a08e98d89c720a08aa837b59313b9cb342f64
Author: William Dillon <wmdillon@me.com>
Date:   Sun May 18 18:08:01 2025 -0400

    first commit

diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..33fbb43
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module code.wmdillon.com/GoApi/increment_version
+
+go 1.24.3
diff --git a/main.go b/main.go
new file mode 100644
index 0000000..03c2393
--- /dev/null
+++ b/main.go
@@ -0,0 +1,143 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+)
+
+type VERSION struct {
+	Filename                                  string
+	Major, Minor, Patch, Revision             uint64
+	HasMajor, HasMinor, HasPatch, HasRevision bool
+}
+
+func (v *VERSION) Flush() error {
+	return os.WriteFile(v.Filename, []byte(v.String()), 0664)
+}
+
+func (v VERSION) String() string {
+	var buffer strings.Builder
+	if v.HasMajor || v.HasMinor || v.HasPatch || v.HasRevision {
+		buffer.WriteString(fmt.Sprintf("%d", v.Major))
+	}
+	if v.HasMinor || v.HasPatch || v.HasRevision {
+		buffer.WriteString(fmt.Sprintf(".%d", v.Minor))
+	}
+	if v.HasPatch || v.HasRevision {
+		buffer.WriteString(fmt.Sprintf(".%d", v.Patch))
+	}
+	if v.HasRevision {
+		buffer.WriteString(fmt.Sprintf("-%d", v.Revision))
+	}
+	return buffer.String()
+}
+
+func NewVersion(filename string) (VERSION, error) {
+	f, err := os.ReadFile(filename)
+	if err != nil {
+		return VERSION{}, fmt.Errorf("error reading %s: %w", filename, err)
+	}
+	fields := strings.FieldsFunc(string(f), func(r rune) bool { return r == '.' || r == '-' })
+	if len(fields) > 4 {
+		return VERSION{}, fmt.Errorf("invalid VERSION file format - %d fields (expected 0-4)", len(fields))
+	}
+	results := VERSION{
+		Filename: filename,
+	}
+	if len(fields) > 0 {
+		results.Major, err = strconv.ParseUint(fields[0], 10, 64)
+		if err != nil {
+			return VERSION{}, fmt.Errorf("error parsing major version: %w", err)
+		}
+		results.HasMajor = true
+	}
+	if len(fields) > 1 {
+		results.Minor, err = strconv.ParseUint(fields[1], 10, 64)
+		if err != nil {
+			return VERSION{}, fmt.Errorf("error parsing minor version: %w", err)
+		}
+		results.HasMinor = true
+	}
+	if len(fields) > 2 {
+		results.Patch, err = strconv.ParseUint(fields[2], 10, 64)
+		if err != nil {
+			return VERSION{}, fmt.Errorf("error parsing patch version: %w", err)
+		}
+		results.HasPatch = true
+	}
+	if len(fields) > 3 {
+		results.Revision, err = strconv.ParseUint(fields[3], 10, 64)
+		if err != nil {
+			return VERSION{}, fmt.Errorf("error parsing revision: %w", err)
+		}
+		results.HasRevision = true
+	}
+	return results, nil
+}
+
+func IncrementVersion(version VERSION, major, minor, patch, revision bool) VERSION {
+	if major {
+		version.Major++
+		version.HasMajor = true
+	}
+	if minor {
+		version.Minor++
+		version.HasMinor = true
+	}
+	if patch {
+		version.Patch++
+		version.HasPatch = true
+	}
+	if revision {
+		version.Revision++
+		version.HasRevision = true
+	}
+	return version
+}
+
+func main() {
+	flag.Usage = func() {
+		fmt.Println("usage: increment_version <path to VERSION file>")
+		fmt.Println("       increment_version <optional flags> <path to VERSION file>")
+		fmt.Println("increment_version increments the version of a given VERSION file.")
+		fmt.Println("It accepts the following formats:")
+		fmt.Println("\t<major>.<minor>.<patch>-<revision>")
+		fmt.Println("\t<major>.<minor>.<patch>")
+		fmt.Println("\t<major>.<minor>")
+		fmt.Println("\t<major>")
+		fmt.Println("the following flags are used to determine which fields to increment.")
+		fmt.Println("using a flag without a corresponding value in the VERSION file will result")
+		fmt.Println("in that field, along with all the necessary fields to the left being")
+		fmt.Println("created inside that file.")
+	}
+	var major, minor, patch, revision, dry bool
+	flag.BoolVar(&major, "major", false, "increment major version")
+	flag.BoolVar(&minor, "minor", false, "increment minor version")
+	flag.BoolVar(&patch, "patch", false, "increment patch version")
+	flag.BoolVar(&revision, "revision", false, "increment revision")
+	flag.BoolVar(&dry, "dry", true, "do not change the file (just print the new version)")
+	flag.Parse()
+	args := flag.Args()
+	if len(args) == 0 {
+		fmt.Println("requires path to VERSION file")
+		flag.Usage()
+		os.Exit(1)
+	}
+	filename := strings.Join(args, " ")
+	oldversion, err := NewVersion(filename)
+	if err != nil {
+		fmt.Printf("error loading version file %s: %v\n", filename, err)
+		os.Exit(1)
+	}
+	newversion := IncrementVersion(oldversion, major, minor, patch, revision)
+	fmt.Printf("'%s' => '%s'\n", oldversion, newversion)
+	if !dry {
+		err = newversion.Flush()
+		if err != nil {
+			fmt.Printf("error writing updated VERSION to %s: %v\n", filename, err)
+		}
+	}
+}
diff --git a/main_test.go b/main_test.go
new file mode 100644
index 0000000..1f1138b
--- /dev/null
+++ b/main_test.go
@@ -0,0 +1,78 @@
+package main
+
+import (
+	"os"
+	"testing"
+)
+
+func TestIncrementVersion(t *testing.T) {
+	const TEST_VERSIONFILE = "main_test-VERSION"
+	err := os.WriteFile(TEST_VERSIONFILE, []byte("0.0.0-0"), 0664)
+	if err != nil {
+		t.Fatalf("error writing %s: %v\n", TEST_VERSIONFILE, err)
+	}
+	defer os.Remove(TEST_VERSIONFILE)
+	version, err := NewVersion(TEST_VERSIONFILE)
+	if err != nil {
+		t.Fatalf("error reading %s: %v\n", TEST_VERSIONFILE, err)
+	}
+	if want, got := "0.0.0-0", version.String(); want != got {
+		t.Fatalf("error: wanted %s; got %s\n", want, got)
+	}
+	version = IncrementVersion(version, false, false, false, true)
+	if want, got := "0.0.0-1", version.String(); want != got {
+		t.Fatalf("error: wanted %s; got %s\n", want, got)
+	}
+	err = version.Flush()
+	if err != nil {
+		t.Fatalf("error flushing: %v\n", err)
+	}
+	version, err = NewVersion(TEST_VERSIONFILE)
+	if err != nil {
+		t.Fatalf("error reading %s: %v\n", TEST_VERSIONFILE, err)
+	} else if want, got := "0.0.0-1", version.String(); want != got {
+		t.Fatalf("error: wanted %s; got %s\n", want, got)
+	}
+	version = IncrementVersion(version, false, false, true, false)
+	if want, got := "0.0.1-1", version.String(); want != got {
+		t.Fatalf("error: wanted %s; got %s\n", want, got)
+	}
+	err = version.Flush()
+	if err != nil {
+		t.Fatalf("error flushing: %v\n", err)
+	}
+	version, err = NewVersion(TEST_VERSIONFILE)
+	if err != nil {
+		t.Fatalf("error reading %s: %v\n", TEST_VERSIONFILE, err)
+	} else if want, got := "0.0.1-1", version.String(); want != got {
+		t.Fatalf("error: wanted %s; got %s\n", want, got)
+	}
+	version = IncrementVersion(version, false, true, false, false)
+	if want, got := "0.1.1-1", version.String(); want != got {
+		t.Fatalf("error: wanted %s; got %s\n", want, got)
+	}
+	err = version.Flush()
+	if err != nil {
+		t.Fatalf("error flushing: %v\n", err)
+	}
+	version, err = NewVersion(TEST_VERSIONFILE)
+	if err != nil {
+		t.Fatalf("error reading %s: %v\n", TEST_VERSIONFILE, err)
+	} else if want, got := "0.1.1-1", version.String(); want != got {
+		t.Fatalf("error: wanted %s; got %s\n", want, got)
+	}
+	version = IncrementVersion(version, true, false, false, false)
+	if want, got := "1.1.1-1", version.String(); want != got {
+		t.Fatalf("error: wanted %s; got %s\n", want, got)
+	}
+	err = version.Flush()
+	if err != nil {
+		t.Fatalf("error flushing: %v\n", err)
+	}
+	version, err = NewVersion(TEST_VERSIONFILE)
+	if err != nil {
+		t.Fatalf("error reading %s: %v\n", TEST_VERSIONFILE, err)
+	} else if want, got := "1.1.1-1", version.String(); want != got {
+		t.Fatalf("error: wanted %s; got %s\n", want, got)
+	}
+}