Issue emicklei#50 (emicklei#60)

* allow nested aggregated constants

option.go

@@ -155,42 +155,66 @@ type NamedLiteral struct {
 	Name string
 }
 
-// parseAggregate reads options written using aggregate syntax
+// parseAggregate reads options written using aggregate syntax.
+// tLEFTCURLY { has been consumed
 func (o *Option) parseAggregate(p *Parser) error {
-	o.AggregatedConstants = []*NamedLiteral{}
+	constants, err := parseAggregateConstants(p, o)
+	o.AggregatedConstants = constants
+	return err
+}
+
+func parseAggregateConstants(p *Parser, container interface{}) (list []*NamedLiteral, err error) {
 	for {
 		pos, tok, lit := p.next()
 		if tRIGHTSQUARE == tok {
 			p.nextPut(pos, tok, lit)
 			// caller has checked for open square ; will consume rightsquare, rightcurly and semicolon
-			return nil
+			return
 		}
 		if tRIGHTCURLY == tok {
-			return nil
+			return
 		}
 		if tSEMICOLON == tok {
 			p.nextPut(pos, tok, lit) // allow for inline comment parsing
-			return nil
+			return
 		}
 		if tCOMMA == tok {
-			if len(o.AggregatedConstants) == 0 {
-				return p.unexpected(lit, "non-empty option aggregate key", o)
+			if len(list) == 0 {
+				err = p.unexpected(lit, "non-empty option aggregate key", container)
+				return
 			}
 			continue
 		}
 		if tIDENT != tok {
-			return p.unexpected(lit, "option aggregate key", o)
+			err = p.unexpected(lit, "option aggregate key", container)
+			return
 		}
 		key := lit
 		pos, tok, lit = p.next()
+		if tLEFTCURLY == tok {
+			nested, fault := parseAggregateConstants(p, container)
+			if fault != nil {
+				err = fault
+				return
+			}
+			// flatten the constants
+			for _, each := range nested {
+				flatten := &NamedLiteral{
+					Name:    key + "." + each.Name,
+					Literal: each.Literal}
+				list = append(list, flatten)
+			}
+			continue
+		}
 		if tCOLON != tok {
-			return p.unexpected(lit, "option aggregate key colon :", o)
+			err = p.unexpected(lit, "option aggregate key colon :", container)
+			return
 		}
 		l := new(Literal)
 		l.Position = pos
-		if err := l.parse(p); err != nil {
-			return err
+		if err = l.parse(p); err != nil {
+			return
 		}
-		o.AggregatedConstants = append(o.AggregatedConstants, &NamedLiteral{Name: key, Literal: l})
+		list = append(list, &NamedLiteral{Name: key, Literal: l})
 	}
 }

option_test.go

@@ -23,7 +23,9 @@
 
 package proto
 
-import "testing"
+import (
+	"testing"
+)
 
 func TestOptionCases(t *testing.T) {
 	for i, each := range []struct {
@@ -136,7 +138,7 @@ option Help = "me"; // inline`
 	}
 }
 
-func TestIssue8(t *testing.T) {
+func TestAggregateSyntax(t *testing.T) {
 	proto := `
 // usage:
 message Bar {
@@ -241,3 +243,54 @@ func TestFieldCustomOptions(t *testing.T) {
 		t.Errorf("got [%v] want [%v]", got, want)
 	}
 }
+
+// issue #50
+func TestNestedAggregateConstants(t *testing.T) {
+	src := `syntax = "proto3";
+
+	package baz;
+
+	option (foo.bar) = {
+	  woot: 100
+	  foo {
+		hello: 200
+		hello2: 300
+		bar {
+			hello3: 400
+		}
+	  }
+	};`
+	p := newParserOn(src)
+	proto, err := p.Parse()
+	if err != nil {
+		t.Error(err)
+	}
+	option := proto.Elements[2].(*Option)
+	if got, want := option.Name, "(foo.bar)"; got != want {
+		t.Errorf("got [%v] want [%v]", got, want)
+	}
+	if got, want := len(option.AggregatedConstants), 4; got != want {
+		t.Errorf("got [%v] want [%v]", got, want)
+	}
+	if got, want := option.AggregatedConstants[0].Name, "woot"; got != want {
+		t.Errorf("got [%v] want [%v]", got, want)
+	}
+	if got, want := option.AggregatedConstants[1].Name, "foo.hello"; got != want {
+		t.Errorf("got [%v] want [%v]", got, want)
+	}
+	if got, want := option.AggregatedConstants[2].Name, "foo.hello2"; got != want {
+		t.Errorf("got [%v] want [%v]", got, want)
+	}
+	if got, want := option.AggregatedConstants[3].Name, "foo.bar.hello3"; got != want {
+		t.Errorf("got [%v] want [%v]", got, want)
+	}
+	if got, want := option.AggregatedConstants[1].Literal.SourceRepresentation(), "200"; got != want {
+		t.Errorf("got [%v] want [%v]", got, want)
+	}
+	if got, want := option.AggregatedConstants[2].Literal.SourceRepresentation(), "300"; got != want {
+		t.Errorf("got [%v] want [%v]", got, want)
+	}
+	if got, want := option.AggregatedConstants[3].Literal.SourceRepresentation(), "400"; got != want {
+		t.Errorf("got [%v] want [%v]", got, want)
+	}
+}