YAPC::EU 2018 Glasgow Update!

Task/Sort-an-integer-array/Forth/sort-an-integer-array-2.fth

@@ -0,0 +1,41 @@
+100000 CONSTANT SIZE
+
+CREATE MYARRAY   SIZE CELLS ALLOT
+
+: []   ( n addr -- addr[n])  SWAP CELLS + ;
+
+: FILLIT ( -- ) ( reversed order)
+  SIZE 0  DO   SIZE I -   I MYARRAY [] !  LOOP ;
+
+: SEEIT  ( -- )
+  SIZE 0 DO  I MYARRAY [] ?   LOOP ;
+
+\ define non-standard words used by Quicksort author
+1 CELLS CONSTANT CELL
+CELL NEGATE CONSTANT -CELL
+: CELL-   CELL - ;
+
+: MID ( l r -- mid ) OVER - 2/ -CELL AND + ;
+
+: EXCH    ( addr1 addr2 -- )
+  OVER @ OVER @        ( read values)
+  SWAP ROT ! SWAP ! ;  ( exchange values)
+
+: PARTITION ( l r -- l r r2 l2 )
+  2DUP MID @ >R ( r: pivot )
+  2DUP
+  BEGIN
+    SWAP BEGIN  DUP @  R@  < WHILE CELL+ REPEAT
+    SWAP BEGIN  R@ OVER @  < WHILE CELL- REPEAT
+    2DUP <= IF 2DUP EXCH  >R CELL+ R> CELL-  THEN
+    2DUP >
+  UNTIL
+  R> DROP ;
+
+: QSORT ( l r -- )
+  PARTITION  SWAP ROT
+  2DUP < IF RECURSE ELSE 2DROP THEN
+  2DUP < IF RECURSE ELSE 2DROP THEN ;
+
+: QUICKSORT ( array len -- )
+  DUP 2 < IF 2DROP EXIT THEN  1- CELLS OVER + QSORT ;

Task/Sort-an-integer-array/Forth/sort-an-integer-array-3.fth

@@ -0,0 +1,2 @@
+FILLIT ok
+MYARRAY SIZE QUICKSORT ok