Data commit

Task/Loops-Nested/Smalltalk/loops-nested-1.st

@@ -0,0 +1,8 @@
+|i|
+
+i := 1.
+[:exit |
+    Transcript showCR:i.
+    i == 5 ifTrue:[ exit value:'stopped' ].
+    i := i + 1.
+] loopWithExit

Task/Loops-Nested/Smalltalk/loops-nested-2.st

@@ -0,0 +1,15 @@
+|i|
+
+i := 1.
+[:exit1 |
+    |j|
+
+    j := 0.
+    [:exit2 |
+        Transcript showCR:('i is %1 / j is %2' bindWith:i with:j).
+        j == 5 ifTrue:[ exit2 value: nil ].
+        i == 5 ifTrue:[ exit1 value: nil ].
+        j := j + 1.
+    ] loopWithExit.
+    i := i + 1
+] loopWithExit

Task/Loops-Nested/Smalltalk/loops-nested-3.st

@@ -0,0 +1,10 @@
+!Block methodsFor:'looping'!
+loopWithExit
+    "the receiver must be a block of one argument.  It is evaluated in a loop forever,
+     and is passed a block, which, if sent a value:-message, will exit the receiver block,
+     returning the parameter of the value:-message. Used for loops with exit in the middle."
+
+    |exitBlock|
+
+    exitBlock := [:exitValue | ^ exitValue].
+    [true] whileTrue:[ self value:exitBlock ]

Task/Loops-Nested/Smalltalk/loops-nested-4.st

@@ -0,0 +1,24 @@
+|v result|
+
+v := 1 to:20 collect:[:i |
+        1 to:20 collect:[:j | Random nextIntegerBetween:1 and:20 ]
+     ].
+
+result :=
+    [:exit |
+        1 to:20 do:[:row |
+            1 to:20 do:[:col |
+                |element|
+
+                (element := (v at:row) at:col) printCR.
+                element == 20 ifTrue:[ exit value:(row @ col) ].
+            ]
+        ].
+        nil
+    ] valueWithExit.
+
+result isNil ifTrue:[
+    'ouch - no 20 found' printCR.
+] ifFalse:[
+    '20 found at ' print. result printCR
+]

Task/Loops-Nested/Smalltalk/loops-nested-5.st

@@ -0,0 +1,49 @@
+"this simple implementation of a bidimensional array
+ lacks controls over the indexes, but has a way of iterating
+ over array's elements, from left to right and top to bottom"
+Object subclass: BiArray [
+  |cols rows elements|
+  BiArray class >> columns: columns  rows: howManyRows [
+      ^ super basicNew init: columns per: howManyRows
+  ]
+  init: columns per: howManyRows [
+     cols := columns.
+     rows := howManyRows.
+     elements := Array new: ( columns * howManyRows )
+  ]
+  calcIndex: biIndex [ "column, row (x,y) to linear"
+    ^ ( (biIndex at: 1) + (((biIndex at: 2) - 1) * cols) )
+  ]
+  at: biIndex [ "biIndex is an indexable containing column row"
+     ^ elements at: (self calcIndex: biIndex).
+  ]
+  directAt: i [ ^ elements at: i ]
+  at: biIndex put: anObject [
+     elements at: (self calcIndex: biIndex) put: anObject
+  ]
+  whileTrue: aBlock do: anotherBlock [
+     |i lim|
+     i := 1. lim := rows * cols.
+     [ ( i <= lim )
+         & (aBlock value: (self directAt: i) )
+     ] whileTrue: [
+         anotherBlock value: (self directAt: i).
+         i := i + 1.
+       ]
+  ]
+].
+
+|biarr|
+biarr := BiArray columns: 10 rows: 10.
+
+"fill the array; this illustrates nested loop but not how to
+ escape from them"
+1 to: 10 do: [ :c |
+  1 to: 10 do: [ :r |
+     biarr at: {c . r} put: (Random between: 1 and: 20)
+  ]
+].
+
+"loop searching for 20; each block gets the element passed as argument"
+biarr whileTrue: [ :v | v ~= 20 ]
+      do: [ :v | v displayNl ]