Self destruct

This programming language uses self destruction to do stuff

Self destruct

the two letters on the side of a symbol is lowercase
aDb - destructs itself and a and b, aka turn those into E
aT - if a is U or B, turn into D
E - turns into S
Sb - turn b into S and S into b, if b is not P or B
aP - if a is S, turn into B
aB - if a is not S, turn into P
aW - if a is U or B, turn into U, else turn into W
aO - if a is U or B, stop program
_ - do nothing

Cool thing

D_____PWWWWWT_PO