FSM Gym attempts to remove unbalanced parenthesis

[mwberry]

Give the regex E((AT*S?)|(ST*A?))?T*Q to the Regex Gym and it reports the following simplification as the first step:

R1: E((AT*S?)|(ST*A?))?T*Q
Rule: ab(cd) => abcd
R2: E(AT*S?)|(ST*A?)?T*Q

I can't accurately represent the color coding it does on the page, but the colored parenthesis indicate it's trying to remove one of the first innermost left parenthesis and the outermost right parenthesis.

[izuzak]

Thanks for reporting this, @mwberry. Here's a screenshot of the behavior just to make it clearer what the problem is: