diff --git a/src/types.hpp b/src/types.hpp
new file mode 100644
index 0000000..0cba471
--- /dev/null
+++ b/src/types.hpp
@@ -0,0 +1,53 @@
+#include <string>
+#include <unordered_map>
+
+enum CommandType {
+  ADD,
+  SUB,
+  NEG,
+
+  EQ,
+  GT,
+  LT,
+
+  AND,
+  OR,
+  NOT,
+
+  PUSH,
+  POP,
+};
+
+enum SegmentType {
+  LCL,
+  ARG,
+  THIS,
+  THAT,
+  STATIC,
+  CONSTANT,
+  TEMP,
+  POINTER,
+};
+
+std::unordered_map<std::string, CommandType> const commandTypes = {
+    {"add", CommandType::ADD}, {"sub", CommandType::SUB},
+    {"neg", CommandType::NEG}, {"eq", CommandType::EQ},
+    {"gt", CommandType::GT},   {"lt", CommandType::LT},
+    {"and", CommandType::AND}, {"or", CommandType::OR},
+    {"not", CommandType::NOT}, {"push", CommandType::PUSH},
+    {"pop", CommandType::POP},
+};
+
+std::unordered_map<std::string, SegmentType> const segmentTypes = {
+    {"local", SegmentType::LCL},     {"argument", SegmentType::ARG},
+    {"this", SegmentType::THIS},     {"that", SegmentType::THAT},
+    {"static", SegmentType::STATIC}, {"constant", SegmentType::CONSTANT},
+    {"temp", SegmentType::TEMP},     {"pointer", SegmentType::POINTER},
+};
+
+typedef struct {
+  std::string line;
+  std::string type;
+  std::string segment;
+  int index;
+} Command;