RAKU QAST: What is It?

While digging into the great language that is Raku, I encountered the term QAST, that stands for the Q Abstract Syntax Tree. Wait a minute! What does that Q stands for? Since I was not able to figure it out, I asked on the #raku IRC channel, and get pointed to a very detailed post by the great guru Damian Conway describing how to extends the Raku grammar to support a for..else statement. While the for...else statement is another idea per-se, at a certain point in the blog post, Damian writes about the QAST, defining it as “Quisquous Abstract Syntax Tree”. But Damian being Damian, this is a joke, as shown in the tooltip:

So essentially, QAST stands for nothing, and it is the normal evaluation of PAST with the P increased into Q for the new version (remember, Raku was originally the next version of Perl).