some fixes

makefile

@@ -8,17 +8,28 @@ TARGET = build/py2rb
 $(TARGET): build/lexer.o build/parser.o build/ParserCtx.o 
 	$(CXX) $^ -o $@
 
-build/lexer.hpp build/lexer.cpp: src/lexer.l build/parser.hpp 
+build/lexer.hpp build/lexer.cpp: src/lexer.l build/parser.hpp build
 	$(FLEX) --header-file=build/lexer.hpp -o build/lexer.cpp src/lexer.l 
 
-build/parser.hpp build/parser.cpp: src/parser.y
+build/parser.hpp build/parser.cpp: src/parser.y build
 	$(BISON) -d -v -o build/parser.cpp src/parser.y
 
-build/lexer.o: build/lexer.cpp
+build/lexer.o: build/lexer.cpp build
 	$(CXX) -c $(ARGS)  $< -o $@
 
-build/parser.o: build/parser.cpp
+build/parser.o: build/parser.cpp build
 	$(CXX) -c $(ARGS)  $< -o $@
 
-build/ParserCtx.o: src/ParserCtx.cpp
+build/ParserCtx.o: src/ParserCtx.cpp build
 	$(CXX) -c $(ARGS)  $< -o $@
+
+build:
+	mkdir -p build
+
+clean: 
+	rm -rf build
+
+run: $(TARGET)
+	$(TARGET)
+
+.PHONY: clean run