--- cool.y	2020-12-22 01:57:18.912461835 +0000
+++ cool.y.work	2020-12-22 01:57:06.089590582 +0000
@@ -11,6 +11,23 @@
   
   extern char *curr_filename;
   
+  /* This is a hack to
+   * a) satisfy the cool compiler which expects yylex to be named cool_yylex (see below)
+   * b) satisfy libfl > 2.5.39 which expects a yylex symbol
+   * c) fix mangling errors of yylex when compiled with a c++ compiler
+   * d) be as non-invasive as possible to the existing assignment code
+   *
+   * WARNING: We are now leaving standard country, but `push_macro` is supported
+   *          in all major compilers.
+   */
+  #pragma push_macro("yylex")
+  #undef yylex
+  int cool_yylex();
+  extern "C" {
+    int (&yylex) (void) = cool_yylex;
+  }
+  #pragma pop_macro("yylex")
+
   
   /* Locations */
   #define YYLTYPE int              /* the type of locations */