i was interested in VistA and what all the fuss was about, so i decided to check it out. turns out the backend is nightmare code that would would swear was machine generated. after some investigation i found out it's MUMPS (Massachusetts General Hospital Utility Multi-Programming System) code. a lot of useful stuff started way back in the 1970s... but MUMPS is a 1960s nightmare come to life.
DENTA1 ;ISC2/SAW,HAG-DENTAL TREATMENT DATA SERVICE REPORTS ; 1/10/89 11:08 AM ; ;;1.2;DENTAL;**24**;JAN 26, 1989
D:'$D(DT) DT^DICRW S %O="OPT",U="^",S=";",O=$T(@(%O)),DENTV=$$VERSION^XPDUTL("DENT") I $D(^DOPT($P(O,S,5),"VERSION")),(DENTV=^DOPT($P(O,S,5),"VERSION")) G IN
K ^DOPT($P(O,S,5))
F I=1:1 Q:$T(@(%O)+I)="" S ^DOPT($P(O,S,5),I,0)=$P($T(@(%O)+I),S,3),^DOPT($P(O,S,5),"B",$P($P($T(@(%O)+I),S,3),"^",1),I)=""
S K=I-1,^DOPT($P(O,S,5),0)=$P(O,S,4)_U_1_U_K_U_K K I,K,X S ^DOPT($P(O,S,5),"VERSION")=DENTV
IN I $P(O,S,6)'="" D @($P(O,S,6))
PR S O=$T(@(%O)),S=";" S IOP=$I D ^%ZIS W:IOST'["PK-" @IOF K IOP
I $P(O,S,7)'="" D @($P(O,S,7))
E W !!,$P(O,S,3),":",!,$$VERSION^XPDUTL("DENT")," ",$P($T(+1),S,1),!!,$P(O,S,4),"S:",!
F J=1:1 Q:'$D(^DOPT($P(O,S,5),J,0)) S K=$S(J0 S Z2=Z1
G:Z3=0 W I Z3>1 S DIC="^DENT(225,",DIC(0)="AEMNQ",DIC("A")="Select STATION.DIVISION: " S:$D(DENTSTA) DIC("B")=$S(DENTSTA[" ":+DENTSTA,1:DENTSTA) D ^DIC Q:Y