hcl: support "." in identifier

hcl/lex.go

@@ -193,7 +193,8 @@ func (x *hclLex) lexId(yylval *hclSymType) int {
 			break
 		}
 
-		if !unicode.IsDigit(c) && !unicode.IsLetter(c) && c != '_' && c != '-' {
+		if !unicode.IsDigit(c) && !unicode.IsLetter(c) &&
+			c != '_' && c != '-' && c != '.' {
 			x.backup()
 
 			if first {

hcl/lex_test.go

@@ -20,6 +20,10 @@ func TestLex(t *testing.T) {
 			"comment_single.hcl",
 			[]int{lexEOF},
 		},
+		{
+			"complex_key.hcl",
+			[]int{IDENTIFIER, EQUAL, STRING, lexEOF},
+		},
 		{
 			"multiple.hcl",
 			[]int{

hcl/test-fixtures/complex_key.hcl

@@ -0,0 +1 @@
+foo.bar = "baz"