diff --git a/CMakeLists.txt b/CMakeLists.txt
index fda821c..0450cd5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -11,7 +11,7 @@ set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
 set(HEADER_FILES src/include/lex.hpp)
 set(SOURCE_FILES src/lex.cpp)
-set(CXX_WARNING_FLAGS -Wall -Wextra -Wpedantic -pedantic -Werror)
+set(CXX_WARNING_FLAGS -Wall -Wextra -Wpedantic -pedantic)
 
 # we're not actually shipping a library yet,
 # this is so we don't have to compile twice for main and tests.
diff --git a/src/include/lex.hpp b/src/include/lex.hpp
index c66b5b0..957e370 100644
--- a/src/include/lex.hpp
+++ b/src/include/lex.hpp
@@ -1,4 +1,5 @@
 #pragma once
+#include <deque>
 #include <sstream>
 #include <vector>
 #include <stdint.h>
@@ -40,8 +41,8 @@ public:
     void feed(std::string);
     
     Token next();
-    std::vector<Token> collect();
+    std::deque<Token> collect();
 };
 
 // when you don't want to construct the object
-std::vector<Token> lex(std::string);
+std::deque<Token> lex(std::string);
diff --git a/src/lex.cpp b/src/lex.cpp
index b8ed457..e4011fd 100644
--- a/src/lex.cpp
+++ b/src/lex.cpp
@@ -9,14 +9,14 @@ using namespace std;
 std::ostream &operator<<(std::ostream &os, Token const &t) { 
     os << "Token(";
     switch (t.type) {
-    case TokenType::OpenParen: os << "OpenParen)"; break;
-    case TokenType::CloseParen: os << "CloseParen)"; break;
-    case TokenType::Dollar: os << "Dollar)"; break;
-    case TokenType::Symbol: os << "Symbol, " << get<string>(*t.value) << ")"; break;
-    case TokenType::String: os << "String, \"" << get<string>(*t.value) << "\")"; break;
-    case TokenType::Int: os << "Int, " << get<int64_t>(*t.value) << ")"; break;
-    case TokenType::Double: os << "Double, " << get<double>(*t.value) << ")"; break;
-    case TokenType::End: os << "END)"; break;
+    case OpenParen: os << "OpenParen)"; break;
+    case CloseParen: os << "CloseParen)"; break;
+    case Dollar: os << "Dollar)"; break;
+    case Symbol: os << "Symbol, " << get<string>(*t.value) << ")"; break;
+    case String: os << "String, \"" << get<string>(*t.value) << "\")"; break;
+    case Int: os << "Int, " << get<int64_t>(*t.value) << ")"; break;
+    case Double: os << "Double, " << get<double>(*t.value) << ")"; break;
+    case End: os << "END)"; break;
     default:
         os << ")";
     }
@@ -146,8 +146,8 @@ Token Lexer::next() {
     }
 }
 
-vector<Token> Lexer::collect() {
-    vector<Token> v;
+deque<Token> Lexer::collect() {
+    deque<Token> v;
     while (true) {
         Token t = next();
         if (t.type == TokenType::End)
@@ -158,7 +158,7 @@ vector<Token> Lexer::collect() {
     return v;
 }
 
-std::vector<Token> lex(std::string s) {
+std::deque<Token> lex(std::string s) {
     Lexer l(s);
     return l.collect();
 }
diff --git a/src/main.cpp b/src/main.cpp
index 5501e6c..9e20c1a 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -8,7 +8,6 @@ int main() {
     string s;
     getline(cin, s);
     cout << s << endl;
-    
     for (auto t : lex(s)) {
         cout << t << " ";
     }