[parenscript-devel] Bug: inconsistent gensym suffixes on what ought to be the same loop control variable - parenscript-devel - mailman3.common-lisp.net

14 Sep 2012


      I just ran into a strange bug where the gensym'd suffixes on loop
control variables change to the wrong thing. The bug appears to be
triggered by a (RETURN) form inside a loop that has more than one
FOR clause. For each extra clause, the suffixes increase by one.
I haven't tried to track down the cause of the bug, but I did just push
a failing test (LOOP-PARALLEL-CLAUSES-WITH-RETURN) to
illustrate it.
(defun-js foo ()
    (loop :for i :from 0 :below 10 :for x = (* i 10)
      :when (> i 5) :do (return x)
      :collect i))
=> (note added comments below):
function foo() {
      return (function () {
          var collect3170 = [];
          var loopResultVarSet3171 = null;
          var loopResultVar3172 = null;
          for (var i = 0; i < 10; i += 1) {
              var x3171 = i * 10;
              if (i > 5) {
                  loopResultVarSet3172 = true;  // <---- suffix should be
3171, not 3172
                  loopResultVar3173 = x3171;    // <---- suffix should be
3172, not 3173
                  break;
              };
              collect3170.push(i);
          };
          if (loopResultVarSet3171) {
              return loopResultVar3172;
          };
          return collect3170;
      })();
  };
Daniel