[mathutil] Add min/max for integer type #123

Makefile

@@ -46,6 +46,7 @@ DOCKER_REPO = dyweb/gommon
 .PHONY: install
 install: fmt test
 	cd ./cmd/gommon && $(GO) install -ldflags "$(FLAGS)" .
+	mv $(GOPATH)/bin/gommonbin $(GOPATH)/bin/gommon
 
 .PHONY: fmt
 fmt:

ROADMAP.md

@@ -26,6 +26,7 @@ From 0.0.9
 - [x] support `.gommonignore`, used by `gommon generate` on `_legacy` folder
 - [x] clean up `.ignore` file support, move it to `fsutil` package
 - [x] clean up `go.mod` by using a separated `go.mod` for `gommon` binary, thus removing cobra, viper, etcd.
+- [x] min/max for integer https://github.com/dyweb/gommon/issues/123
 
 ## Finished
 

generator/gotmpl.go

@@ -5,6 +5,7 @@ import (
 	"go/format"
 	"io/ioutil"
 	"text/template"
+	"unicode"
 
 	"github.com/dyweb/gommon/errors"
 	"github.com/dyweb/gommon/util/fsutil"
@@ -29,7 +30,11 @@ func (c *GoTemplateConfig) Render(root string) error {
 	if b, err = ioutil.ReadFile(join(root, c.Src)); err != nil {
 		return errors.Wrap(err, "can't read template file")
 	}
-	if t, err = template.New(c.Src).Parse(string(b)); err != nil {
+	if t, err = template.New(c.Src).
+		Funcs(template.FuncMap{
+			"UcFirst": UcFirst,
+		}).
+		Parse(string(b)); err != nil {
 		return errors.Wrap(err, "can't parse template")
 	}
 	buf.WriteString(genutil.DefaultHeader(join(root, c.Src)))
@@ -49,3 +54,14 @@ func (c *GoTemplateConfig) Render(root string) error {
 	log.Debugf("rendered go tmpl %s to %s", join(root, c.Src), join(root, c.Dst))
 	return nil
 }
+
+// UcFirst change first character to upper case.
+// It is based on https://github.com/99designs/gqlgen/blob/master/codegen/templates/templates.go#L205
+func UcFirst(s string) string {
+	if s == "" {
+		return ""
+	}
+	r := []rune(s)
+	r[0] = unicode.ToUpper(r[0])
+	return string(r)
+}

generator/gotmpl_test.go

@@ -1 +1,22 @@
 package generator_test
+
+import (
+	"bytes"
+	"testing"
+	"text/template"
+
+	"github.com/dyweb/gommon/generator"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestUcFirst(t *testing.T) {
+	tmpl, err := template.New("test_ucfirst").Funcs(template.FuncMap{"UcFirst": generator.UcFirst}).Parse(`{{ .foo | UcFirst }}`)
+	require.Nil(t, err)
+	var buf bytes.Buffer
+	err = tmpl.Execute(&buf, map[string]string{
+		"foo": "int64",
+	})
+	assert.Nil(t, err)
+	assert.Equal(t, "Int64", buf.String())
+}

util/mathutil/gommon.yml

@@ -0,0 +1,11 @@
+gotmpls:
+  - src: max_generated.go.tmpl
+    dst: max_generated.go
+    go: true
+    data:
+      - int
+      - uint
+      - int32
+      - uint32
+      - int64
+      - uint64

util/mathutil/max.go

@@ -0,0 +1,8 @@
+package mathutil
+
+func MaxInt(a, b int) int {
+	if a > b {
+		return a
+	}
+	return b
+}

util/mathutil/max_generated.go.tmpl

@@ -0,0 +1,17 @@
+package mathutil
+
+{{ range .}}
+func Max{{. | UcFirst }} (a, b {{.}}) {{.}} {
+    if a > b {
+        return a
+    }
+    return b
+}
+
+func Min{{. | UcFirst }} (a, b {{.}}) {{.}} {
+    if a < b {
+        return a
+    }
+    return b
+}
+{{ end }}

util/mathutil/pkg.go

@@ -0,0 +1,2 @@
+// Package mathutil provides supplement functions for math package, e.g. MaxInt, MaxInt64
+package mathutil