fix Issue emicklei#8, aggregate option syntax case

.gitignore

@@ -1,3 +1,4 @@
 cmd/proto2xsd/sample.proto
 cmd/proto2xsd/proto2xsd
-cmd/protofmt/protofmt
+cmd/protofmt/protofmt
+debug.test

option.go

@@ -169,8 +169,22 @@ func (o *Option) parseAggregate(p *Parser) error {
 	o.AggregatedConstants = []*NamedLiteral{}
 	for {
 		tok, lit := p.scanIgnoreWhitespace()
+		if tRIGHTSQUARE == tok {
+			p.unscan()
+			// caller has checked for open square ; will consume rightsquare, rightcurly and semicolon
+			return nil
+		}
 		if tRIGHTCURLY == tok {
-			break
+			continue
+		}
+		if tSEMICOLON == tok {
+			return nil
+		}
+		if tCOMMA == tok {
+			if len(o.AggregatedConstants) == 0 {
+				return p.unexpected(lit, "non-empty option aggregate key", o)
+			}
+			continue
 		}
 		if tIDENT != tok {
 			return p.unexpected(lit, "option aggregate key", o)
@@ -186,9 +200,4 @@ func (o *Option) parseAggregate(p *Parser) error {
 		}
 		o.AggregatedConstants = append(o.AggregatedConstants, &NamedLiteral{Name: key, Literal: l})
 	}
-	tok, lit := p.scanIgnoreWhitespace()
-	if tSEMICOLON != tok {
-		return p.unexpected(lit, "option aggregate end ;", o)
-	}
-	return nil
 }

option_test.go

@@ -126,3 +126,42 @@ option Help = "me"; // inline`
 		t.Fatalf("got [%v] want [%v]", got, want)
 	}
 }
+
+func TestIssue8(t *testing.T) {
+	proto := `
+// usage:
+message Bar {
+  // alternative aggregate syntax (uses TextFormat):
+  int32 b = 2 [(foo_options) = {
+    opt1: 123,
+    opt2: "baz"
+  }];
+}
+	`
+	p := newParserOn(proto)
+	pr, err := p.Parse()
+	if err != nil {
+		t.Fatal(err)
+	}
+	o := pr.Elements[0].(*Message)
+	f := o.Elements[0].(*NormalField)
+	if got, want := len(f.Options), 1; got != want {
+		t.Fatalf("got [%v] want [%v]", got, want)
+	}
+	ac := f.Options[0].AggregatedConstants
+	if got, want := len(ac), 2; got != want {
+		t.Fatalf("got [%v] want [%v]", got, want)
+	}
+	if got, want := ac[0].Name, "opt1"; got != want {
+		t.Fatalf("got [%v] want [%v]", got, want)
+	}
+	if got, want := ac[1].Name, "opt2"; got != want {
+		t.Fatalf("got [%v] want [%v]", got, want)
+	}
+	if got, want := ac[0].Source, "123"; got != want {
+		t.Fatalf("got [%v] want [%v]", got, want)
+	}
+	if got, want := ac[1].Source, "baz"; got != want {
+		t.Fatalf("got [%v] want [%v]", got, want)
+	}
+}