Add tasks for all the new languages

Task/Forward-difference/EchoLisp/forward-difference.echolisp

@@ -0,0 +1,7 @@
+(define (Δ-1 list)
+(for/list ([x (cdr list)] [y list]) (- x y)))
+
+(define (Δ-n n) (iterate Δ-1 n))
+
+((Δ-n 9) '(90 47 58 29 22 32 55 5 55 73))
+    →  (-2921)

Task/Forward-difference/Lasso/forward-difference.lasso

@@ -0,0 +1,16 @@
+#!/usr/bin/lasso9
+
+define forwardDiff(values, order::integer=1) => {
+  !#order ? return #values->asArray
+  local(result = array)
+  iterate(#values) => {
+    loop_count < #values->size ?
+      #result->insert(#values->get(loop_count+1) - #values->get(loop_count))
+  }
+  #order > 1 ? #result = forwardDiff(#result, #order-1)
+  return #result
+}
+
+local(data = (:90, 47, 58, 29, 22, 32, 55, 5, 55, 73))
+with x in generateSeries(0, #data->size-1)
+do stdoutnl(#x + ': ' + forwardDiff(#data, #x))

Task/Forward-difference/Nim/forward-difference.nim

@@ -0,0 +1,13 @@
+proc dif(s): seq[int] =
+  result = newSeq[int](s.len-1)
+  for i, x in s[1..s.high]:
+    result[i] = x - s[i]
+
+proc difn(s, n): seq[int] =
+  if n > 0: difn(dif(s), n-1)
+  else: s
+
+const s = @[90, 47, 58, 29, 22, 32, 55, 5, 55, 73]
+echo difn(s, 0)
+echo difn(s, 1)
+echo difn(s, 2)

Task/Forward-difference/Oforth/forward-difference.oforth

@@ -0,0 +1,2 @@
+: forwardDiff(l)     l right(l size 1 -) l zipWith(#-) ;
+: forwardDiffN(n, l)  l #[ forwardDiff dup println ] times(n) ;

Task/Forward-difference/Sidef/forward-difference.sidef

@@ -0,0 +1,15 @@
+func dif(arr) {
+    gather {
+        range(0, arr.end-1).each { |i|
+            take(arr[i+1] - arr[i]);
+        }
+    }
+}
+
+func difn(n, arr) {
+    n.times { arr = dif(arr) };
+    arr;
+}
+
+say dif([1, 23, 45, 678]);       # => [22, 22, 633]
+say difn(2, [1, 23, 45, 678]);   # => [0, 611]

Task/Forward-difference/Visual-FoxPro/forward-difference.visual

@@ -0,0 +1,37 @@
+#DEFINE CTAB CHR(9)
+LOCAL lcList As String, i As Integer, n As Integer
+n = 10
+LOCAL ARRAY aa[n]
+CLEAR
+lcList = "90,47,58,29,22,32,55,5,55,73"
+FOR i = 1 TO n
+    aa[i] = VAL(GETWORDNUM(lcList, i, ","))
+ENDFOR
+ShowOutput("Original", @aa)
+k = n - 1
+FOR i = 1 TO n - 1
+    ForwardDiff(@aa)
+    ShowOutput("Difference " + TRANSFORM(i), @aa)
+ENDFOR
+
+PROCEDURE ForwardDiff(a)
+LOCAL i As Integer, n As Integer
+n = ALEN(a)
+LOCAL ARRAY b[n-1]
+FOR i = 1 TO n - 1
+    b[i] = a[i+1] - a[i]
+ENDFOR
+DIMENSION a[n-1]
+ACOPY(b, a)
+ENDPROC
+
+PROCEDURE ShowOutput(lcLabel, zz)
+LOCAL i As Integer, n As Integer, lcTxt As String
+n = ALEN(zz)
+lcTxt = lcLabel + ":" + CTAB
+FOR i = 1 TO n
+    lcTxt = lcTxt + TRANSFORM(zz[i]) + CTAB
+ENDFOR
+lcTxt = LEFT(lcTxt, LEN(lcTxt) - 1)
+? lcTxt
+ENDPROC	

Task/Forward-difference/jq/forward-difference-1.jq

@@ -0,0 +1,8 @@
+# If n is a non-negative number and if input is
+# a (possibly empty) array of numbers,
+# emit an array, even if the input list is too short:
+def ndiff(n):
+  if n==0 then .
+  elif n == 1 then . as $in | [range(1;length) | $in[.] - $in[.-1]]
+  else ndiff(1) | ndiff(n-1)
+  end;

Task/Forward-difference/jq/forward-difference-2.jq

@@ -0,0 +1,3 @@
+def s: [90, 47, 58, 29, 22, 32, 55, 5, 55, 73];
+
+range(0;12) as $i | (s|ndiff($i))

Task/Forward-difference/jq/forward-difference-3.jq

@@ -0,0 +1,13 @@
+$ jq -c -n -f forward-difference.jq
+[90,47,58,29,22,32,55,5,55,73]
+[-43,11,-29,-7,10,23,-50,50,18]
+[54,-40,22,17,13,-73,100,-32]
+[-94,62,-5,-4,-86,173,-132]
+[156,-67,1,-82,259,-305]
+[-223,68,-83,341,-564]
+[291,-151,424,-905]
+[-442,575,-1329]
+[1017,-1904]
+[-2921]
+[]
+[]