diff --git a/build.sh b/build.sh
index 3df45d8..405f55e 100644
--- a/build.sh
+++ b/build.sh
@@ -1,20 +1,4 @@
-# set -euo pipefail
-
-assert_eq() {
-   expected="$1"
-   actual="$2"
-   if [ "$expected" != "$actual" ]; then
-       echo "assert failed: expected '$expected', got '$actual'"
-       exit 1
-   fi
-}
-
-verify_expr() {
-    ./main "$1"
-    clang out.s -o test
-    ./test
-    assert_eq $? $2
-}
+set -euo pipefail
 
 if [[ ! -e build ]]; then
     mkdir build
@@ -23,10 +7,4 @@ cd build
 clang -o meta $(realpath ../meta.c) -g -Wall -Wextra -Wshadow -fdiagnostics-absolute-paths
 ./meta > ../meta_gen.c
 clang -o main $(realpath ../main.c) -g -Wall -Wextra -Wshadow -fdiagnostics-absolute-paths
-
 ./main
-verify_expr "2+1-1" 2
-verify_expr "(2+1-1)*3" 6
-
-
-echo done
\ No newline at end of file
diff --git a/emit_asm_x64.c b/emit_asm_x64.c
index 054c028..ee077af 100644
--- a/emit_asm_x64.c
+++ b/emit_asm_x64.c
@@ -32,3 +32,21 @@ void emit_program(FILE *file, Ast *n) {
     emit_expr(file, n);
     fprintf(file, "    ret\n");
 }
+
+void emit_expr_test(char *expr, int value) {
+    Token_Array tokens = lex_file("expr", expr, strlen(expr));
+    Parser parser = {tokens.data, tokens.data + tokens.len};
+    Ast *ast = parse_expr(&parser, 0);
+    FILE *file = fopen("out.s", "w");
+    emit_program(file, ast);
+    fclose(file);
+    int result = system("clang out.s -o out");
+    assert(result == 0);
+    result = system("./out");
+    assert(WEXITSTATUS(result) == value);
+}
+
+void emit_x64_test(void) {
+    emit_expr_test("10+5*2-10", 10+5*2-10);
+    printf("x64 tests passed\n");
+}
\ No newline at end of file
diff --git a/lex.c b/lex.c
index 5b1f85c..8949f94 100644
--- a/lex.c
+++ b/lex.c
@@ -44,24 +44,7 @@ void lex_advance(Lexer *lex) {
         lex->column++;
     }
 
-    if (*lex->at == '\\') {
-        lex->at += 1;
-        if ((lex->at < lex->end) && *lex->at == '\n') {
-            lex->at += 1;
-            lex->line += 1; lex->column = 0;
-        } else if ((lex->at < lex->end) && *lex->at == '\r') {
-            lex->at += 1;
-            if ((lex->at < lex->end) && *lex->at == '\n') {
-                lex->at += 1;
-                lex->line += 1; lex->column = 0;
-            } else {
-                panicf("after \\r missing \\n");
-            }
-        } else {
-            panicf("stray '\\' without follow up new line");
-        }
-
-    } else if (*lex->at == '\n') {
+   if (*lex->at == '\n') {
         lex->preproc = false;
         lex->at += 1;
     } else {
diff --git a/main.c b/main.c
index 6b56a74..47188c1 100644
--- a/main.c
+++ b/main.c
@@ -12,17 +12,9 @@
 #include "parser.c"
 #include "emit_asm_x64.c"
 
-int main(int argc, char **argv) {
-    if (argc == 2) {
-        Token_Array tokens = lex_file("expr", argv[1], strlen(argv[1]));
-        Parser parser = {tokens.data, tokens.data + tokens.len};
-        Ast *ast = parse_expr(&parser, 0);
-        FILE *file = fopen("out.s", "w");
-        emit_program(file, ast);
-        fclose(file);
-    } else {
-        vec_test();
-        lex_test();
-        parser_test();
-    }
+int main() {
+    vec_test();
+    lex_test();
+    parser_test();
+    emit_x64_test();
 }
\ No newline at end of file