🚀 go-pugleaf

>In the following, the line 'print "class:"$0' prints nothing as the code now stands.
>HOwever, by uncommenting 'print class[$2]', the above DOES print.
>What am i doing wrong? (fails even in this stripped eg)

   By referencing class[$2], you are automatically creating an index in
class even if it didn't exist previously.  Thus, when you uncomment this
line you are causing the condition "if ($2 in class)" to become true.

   The reason why the print "class:"$0 doesn't get printed is that that
particular block doesn't get executed at all as the code now stands. 

>...
>#       print class[$2]  #bad side effect: this creates entry for $2 w/ null value
>    if ($2 in class) {
>     print "class:"$0
>    }
>...