aligning message fields

Change-Id: I4c70397e4ac6e9ddfd3577ab59a919c0f7adbad5

aligned.go

@@ -7,7 +7,12 @@ type aligned struct {
 	left   bool
 }
 
-var alignedEquals = leftAligned(" = ")
+var (
+	alignedEquals      = leftAligned(" = ")
+	alignedShortEquals = leftAligned("=")
+	alignedSpace       = leftAligned(" ")
+	alignedComma       = leftAligned(",")
+)
 
 func leftAligned(src string) aligned  { return aligned{src, true} }
 func rightAligned(src string) aligned { return aligned{src, false} }

cmd/protofmt/unformatted.proto

@@ -50,7 +50,7 @@ message Message
   STARTED = 1;
   RUN = 2 [(custom_option) = "hello world"];
 }
-}
+} // end message
 
 
 service SearchService { // comment

field.go

@@ -1,5 +1,7 @@
 package proto
 
+import "strconv"
+
 // Field is an abstract message field.
 type Field struct {
 	Name     string
@@ -22,6 +24,27 @@ func (f *NormalField) Accept(v Visitor) {
 	v.VisitNormalField(f)
 }
 
+// columns returns printable source tokens
+func (f *NormalField) columns() (cols []aligned) {
+	if f.Repeated {
+		cols = append(cols, leftAligned("repeated "))
+	} else {
+		cols = append(cols, alignedSpace)
+	}
+	cols = append(cols, leftAligned(f.Name), rightAligned(f.Type), alignedEquals, rightAligned(strconv.Itoa(f.Sequence)))
+	if len(f.Options) > 0 {
+		cols = append(cols, leftAligned(" ["))
+		for i, each := range f.Options {
+			if i > 0 {
+				cols = append(cols, alignedComma)
+			}
+			cols = append(cols, each.keyValuePair()...)
+		}
+		cols = append(cols, leftAligned("]"))
+	}
+	return
+}
+
 // parse expects:
 // [ "repeated" | "optional" ] type fieldName "=" fieldNumber [ "[" fieldOptions "]" ] ";"
 func (f *NormalField) parse(p *Parser) error {

formatter_test.go

@@ -28,8 +28,8 @@ func TestPrintListOfColumns(t *testing.T) {
 	b := new(bytes.Buffer)
 	f := NewFormatter(b, " ")
 	f.printListOfColumns(list)
-	formatted := `A   =  1 [a  = 1234];
-ABC = 12 [ab = 1234];
+	formatted := `A   =  1 [a =1234];
+ABC = 12 [ab=1234];
 `
 	if got, want := b.String(), formatted; got != want {
 		t.Errorf("got [%v] want [%v]", got, want)

option.go

@@ -22,13 +22,18 @@ func (o *Option) columns() (cols []aligned) {
 	} else {
 		cols = append(cols, leftAligned(" ["))
 	}
-	cols = append(cols, leftAligned(o.Name), alignedEquals, rightAligned(o.Constant.String()))
+	cols = append(cols, o.keyValuePair()...)
 	if o.IsEmbedded {
 		cols = append(cols, leftAligned("]"))
 	}
 	return
 }
 
+// keyValuePair returns key = value or "value"
+func (o *Option) keyValuePair() (cols []aligned) {
+	return append(cols, leftAligned(o.Name), alignedShortEquals, rightAligned(o.Constant.String()))
+}
+
 // parse reads an Option body
 // ( ident | "(" fullIdent ")" ) { "." ident } "=" constant ";"
 func (o *Option) parse(p *Parser) error {