September Morn Update

Task/Run-length-encoding/Smalltalk/run-length-encoding-1.st

@@ -0,0 +1,34 @@
+|compress decompress|
+compress := [:string |
+   String streamContents:[:out |
+       |count prev|
+
+       count := 0.
+       (string,'*')  "trick to avoid final run handling in loop"
+          inject:nil
+          into:[:prevChar :ch |
+              ch ~= prevChar ifTrue:[
+                  count = 0 ifFalse:[
+                      count printOn:out.
+                      out nextPut:prevChar.
+                      count := 0.
+                  ].
+              ].
+              count := count + 1.
+              ch
+          ]
+   ]
+].
+
+decompress := [:string |
+   String streamContents:[:out |
+       string readingStreamDo:[:in |
+           [in atEnd] whileFalse:[
+               |n ch|
+               n := Integer readFrom:in.
+               ch := in next.
+               out next:n put:ch.
+            ]
+       ]
+   ].
+].

Task/Run-length-encoding/Smalltalk/run-length-encoding-2.st

@@ -0,0 +1,5 @@
+compress value:'WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW'
+-> '12W1B12W3B24W1B14W'
+
+decompress value:'12W1B12W3B24W1B14W'
+-> 'WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW'

Task/Run-length-encoding/Smalltalk/run-length-encoding-3.st

@@ -0,0 +1,4 @@
+compress := [:string |
+    String streamContents:[:out |
+        string asRunArray runsDo:[:count :char |
+            count printOn:out. out nextPut:char]]].