Merge pull request #27 from phelmkamp/equal

implement `equal` directive

README.md

@@ -77,6 +77,12 @@ Includes the field in the result of the generated `String` method. Uses value re
 
 Includes the field as an argument to the generated `New$Type` method.
 
+`equal`
+
+Includes the field in the generated `Equal` method.
+Specify the `reflect` option to compare the field using `reflect.DeepEqual`.
+Uses value receiver by default.
+
 `ptr`
 
 Specifies that a pointer receiver be used for all subsequent directives.

directive/directive.go

@@ -12,6 +12,7 @@ import (
 const (
 	optOmitField = "omitfield"
 	optStringer  = "stringer"
+	optReflect   = "reflect"
 )
 
 // Target represents the target of the directive
@@ -255,6 +256,49 @@ func New(tgt *Target) {
 	}
 }
 
+// Equal adds each name of the given field to the Equal() implementation
+func Equal(tgt *Target, opts []string) {
+	for _, fldNm := range tgt.FldNames {
+		log.Print("Adding to method: Equal\n")
+		found := tgt.MetaFile.FilterMethods(
+			func(m *meta.Method) bool {
+				return m.RcvName == tgt.RcvName && m.RcvType == tgt.RcvType && m.Name == "Equal"
+			},
+			1,
+		)
+		var cmps string
+		var equal *meta.Method
+		if len(found) > 0 {
+			equal = found[0]
+			cmps = equal.Misc["Cmps"].(string) + "\n\t"
+		} else {
+			equal = &meta.Method{
+				RcvName: tgt.RcvName,
+				RcvType: tgt.RcvType,
+				Name:    "Equal",
+				Misc:    make(map[string]interface{}),
+				Tmpl:    "equal",
+			}
+			tgt.MetaFile.Methods = append(tgt.MetaFile.Methods, equal)
+		}
+		var cmp string
+		if len(opts) > 0 && opts[0] == optReflect {
+			log.Print("Adding import: \"reflect\"\n")
+			tgt.MetaFile.Imports["reflect"] = struct{}{}
+			cmp = fmt.Sprintf(
+				"if !reflect.DeepEqual(%s.%s, %s2.%s) {\n\t\treturn false\n\t}",
+				tgt.RcvName, fldNm, tgt.RcvName, fldNm,
+			)
+		} else {
+			cmp = fmt.Sprintf(
+				"if %s.%s != %s2.%s {\n\t\treturn false\n\t}",
+				tgt.RcvName, fldNm, tgt.RcvName, fldNm,
+			)
+		}
+		equal.Misc["Cmps"] = cmps + cmp
+	}
+}
+
 func first(s string) (string, int) {
 	if s == "" {
 		return "", 0

internal/testdata/foo.go

@@ -15,9 +15,9 @@ type Foo struct {
 }
 
 type Bar struct {
-	name  string             `meta:"stringer"`
+	name  string             `meta:"stringer;equal"`
 	foos  []Foo              `meta:"getter;setter;map:string"`
 	pairs map[string]float64 `meta:"getter;setter"`
-	times []time.Time        `meta:"getter;setter;filter;map:int64"`
+	times []time.Time        `meta:"getter;setter;filter;map:int64;equal,reflect"`
 	baz   bool               `meta:"setter"`
 }

internal/testdata/foo_meta.go

@@ -3,8 +3,9 @@
 package testdata
 
 import (
-	"fmt"
 	"time"
+	"fmt"
+	"reflect"
 )
 
 // NewFoo creates a new Foo with the given initial values.
@@ -88,6 +89,22 @@ func (b Bar) String() string {
 	return fmt.Sprintf("%v", b.name)
 }
 
+// Equal answers whether v is equivalent to b.
+// Always returns false if v is not a Bar.
+func (b Bar) Equal(v interface{}) bool {
+	b2, ok := v.(Bar)
+	if !ok {
+		return false
+	}
+	if b.name != b2.name {
+		return false
+	}
+	if !reflect.DeepEqual(b.times, b2.times) {
+		return false
+	}
+	return true
+}
+
 // Foos returns the value of foos.
 func (b Bar) Foos() []Foo {
 	return b.foos

main.go

@@ -180,6 +180,8 @@ func main() {
 							directive.Stringer(&fldTgt)
 						case "new":
 							directive.New(&fldTgt)
+						case "equal":
+							directive.Equal(&fldTgt, opts)
 						default:
 							log.Printf("Unknown directive: %s\n", d)
 						}

meta/templates/equal.tmpl

@@ -0,0 +1,10 @@
+// Equal answers whether v is equivalent to {{.RcvName}}.
+// Always returns false if v is not a {{.RcvType}}.
+func ({{.RcvName}} {{.RcvType}}) Equal(v interface{}) bool {
+	{{.RcvName}}2, ok := v.({{.RcvType}})
+	if !ok {
+		return false
+	}
+	{{.Misc.Cmps}}
+	return true
+}