diff --git a/include/parser.h b/include/parser.h
index 6ab8f294..5dcc671e 100644
--- a/include/parser.h
+++ b/include/parser.h
@@ -24,6 +24,7 @@ extern "C" {
 #endif
     
 static int INITIAL_STACK_SIZE = 100;
+static const char *ts_symbol_names[];
 
 typedef int TSState;
 
@@ -36,6 +37,7 @@ typedef struct {
     const char *input;
     size_t position;
     TSTree *lookahead_node;
+    TSTree *prev_lookahead_node;
     TSState lex_state;
     TSStackEntry *stack;
     size_t stack_size;
@@ -81,7 +83,8 @@ static void TSParserShift(TSParser *parser, TSState parse_state) {
     TSStackEntry *entry = (parser->stack + parser->stack_size);
     entry->state = parse_state;
     entry->node = parser->lookahead_node;
-    parser->lookahead_node = NULL;
+    parser->lookahead_node = parser->prev_lookahead_node;
+    parser->prev_lookahead_node = NULL;
     parser->stack_size++;
 }
 
@@ -93,8 +96,9 @@ static void TSParserReduce(TSParser *parser, TSSymbol symbol, int child_count) {
         children[i] = parser->stack[parser->stack_size + i].node;
     }
     
+    parser->prev_lookahead_node = parser->lookahead_node;
     parser->lookahead_node = TSTreeMake(symbol, child_count, children);
-    DEBUG_PARSE("reduce: %ld, state: %u \n", symbol, TSParserParseState(parser));
+    DEBUG_PARSE("reduce: %s, state: %u \n", ts_symbol_names[symbol], TSParserParseState(parser));
 }
 
 static void TSParserError(TSParser *parser, size_t count, const char **expected_inputs) {
@@ -132,6 +136,7 @@ static void TSParserSetLookaheadSym(TSParser *parser, TSSymbol symbol) {
 
 static void TSParserAcceptInput(TSParser *parser) {
     parser->result.tree = parser->stack[parser->stack_size - 1].node;
+    DEBUG_PARSE("accept \n");
 }
 
 #pragma mark - DSL
diff --git a/spec/runtime/arithmetic_spec.cpp b/spec/runtime/arithmetic_spec.cpp
index 45fb64ef..a4cde825 100644
--- a/spec/runtime/arithmetic_spec.cpp
+++ b/spec/runtime/arithmetic_spec.cpp
@@ -15,12 +15,24 @@ describe("arithmetic", []() {
     
     it("parses variables", [&]() {
         TSDocumentSetText(document, "x");
-        AssertThat(string(TSDocumentToString(document)), Equals("(expression (term (factor (variable))))"));
+        AssertThat(string(TSDocumentToString(document)), Equals(
+            "(expression (term (factor (variable))))"));
     });
 
     it("parses products of variables", [&]() {
         TSDocumentSetText(document, "x*y");
-        AssertThat(string(TSDocumentToString(document)), Equals("(expression (term (factor (variable)) (3) (factor (variable))))"));
+        AssertThat(string(TSDocumentToString(document)), Equals(
+            "(expression (term (factor (variable)) (3) (factor (variable))))"));
+    });
+    
+    it("parses complex trees", [&]() {
+        TSDocumentSetText(document, "x*y+z*a");
+        AssertThat(string(TSDocumentToString(document)), Equals(
+            "(expression (term (factor (variable)) (3) (factor (variable))) (4) (term (factor (variable)) (3) (factor (variable))))"));
+
+        TSDocumentSetText(document, "x*(y+z)");
+        AssertThat(string(TSDocumentToString(document)), Equals(
+            "(expression (term (factor (variable)) (3) (factor (1) (expression (term (factor (variable))) (4) (term (factor (variable)))) (2))))"));
     });
 });
 
diff --git a/src/runtime/parse_config.cpp b/src/runtime/parse_config.cpp
index bc5d9f62..4e33b8ed 100644
--- a/src/runtime/parse_config.cpp
+++ b/src/runtime/parse_config.cpp
@@ -19,7 +19,7 @@ const char * TSParseErrorToString(const TSParseError *error, const char *input_s
     
     result += "Expected: ";
     for (int i = 0; i < error->expected_input_count; i++)
-        result += error->expected_inputs[i];
+        result += string(error->expected_inputs[i]) + " ";
 
     char *stuff = (char *)malloc(result.size() * sizeof(char));
     strcpy(stuff, result.c_str());