▁of ▁the ▁WH I LE / RE PE AT / END ▁block ▁is : ▁▁▁ ▁WH I LE ▁condition ▁RE PE AT ▁loop _ statement ▁END ▁ ▁DO / UNT IL / END ▁The ▁DO / UNT IL / END ▁block ▁in ▁R PL ▁supports ▁an ▁in defin ite ▁loop ▁with ▁the ▁condition ▁test ▁at ▁the ▁end ▁of ▁the ▁loop . ▁ ▁The ▁syntax ▁of ▁the ▁DO / UNT IL / END ▁block ▁is : ▁▁▁ ▁DO ▁loop _ statement ▁UN T IL ▁condition ▁END ▁ ▁Notes ▁▁ 1 . ▁" R PL " ▁is ▁derived ▁from ▁Re verse ▁Polish ▁L isp ▁according ▁to ▁its ▁original ▁developers , ▁while ▁for ▁a ▁short ▁time ▁in ▁ 1 9 8 7 ▁H P ▁market ing ▁attempted ▁to ▁coin ▁the ▁back ron ym ▁R OM - based ▁Pro ced ural ▁Language ▁for ▁it . ▁In ▁addition , ▁the ▁R PL ▁initial s ▁are ▁sometimes ▁interpreted ▁as ▁Re verse ▁Polish ▁Log ic , ▁or ▁Re verse ▁Polish ▁Language , ▁but ▁these ▁names ▁are ▁not ▁official . ▁ ▁See ▁also ▁A ▁Program ming ▁Language ▁( AP L ) ▁FO C AL ▁ke yst roke ▁programming ▁High ▁Performance ▁Language ▁( HP L ) ▁H P ▁trig raph s ▁Prime ▁Program ming ▁Language ▁( P PL ) ▁R PL ▁character ▁set ▁ ▁References ▁ ▁Further ▁reading ▁▁▁▁▁▁▁▁▁▁▁▁ ▁( Old er ▁version : ▁) ▁ ▁External ▁links ▁▁▁▁▁▁▁▁ ▁( a ▁G PL ▁lic ensed ▁R PL ▁clone ) ▁▁▁ ▁( an ▁open ▁source ▁R PL ▁derivative ▁for ▁the ▁H P ▁