thanks, everyone. A sandbox alone is not trustworthy enough.

the problem is intrinsically pretty bad. public internet. And I want one user to make up a question for another anonymous user to answer. (this also means that 'javascript as sandbox' won't work.)

User 1 inputs something like 

   $x=round(rand(),1);
   print "If x is $x, then what is x^2?";

[download]

User 2 may see 

   if x is 0.5, then what is x^2?

[download]

The '0.5' is obviously computed, based on what user 1 provided. I need to avoid user 1 inputting mischief.

Finally, user 1 receives back what the answer was that user 2 gave and can check whether it was correct. because answers are not algorithms (the way questions are), I can easily sanitize what user 2 provides.

Do I really have to write my own language and parser for this? no one else has?

regards, /iaw

In reply to Re^2: embedding a safe unescapable mini perl interpreter? by iaw4
in thread embedding a safe unescapable mini perl interpreter? by iaw4

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