2016 Update

Task/Amb/Perl-6/amb-1.pl6

@@ -1,18 +1,18 @@
-sub infix:<lf> ($a,$b) {
-    next unless try $a.substr(*-1,1) eq $b.substr(0,1);
-    "$a $b";
+#| an array of four words, that have more possible values.
+#| Normally we would want `any' to signify we want any of the values, but well negate later and thus we need `all'
+my @a =
+(all «the that a»),
+(all «frog elephant thing»),
+(all «walked treaded grows»),
+(all «slowly quickly»);
+
+sub test (Str $l, Str $r) {
+    $l.ends-with($r.substr(0,1))
 }
 
-multi dethunk(Callable $x) { try take $x() }
-multi dethunk(     Any $x) {     take $x   }
-
-sub amb (*@c) { gather @c».&dethunk }
-
-say first *, do
-    amb(<the that a>, { die 'oops'}) Xlf
-    amb('frog',{'elephant'},'thing') Xlf
-    amb(<walked treaded grows>)      Xlf
-    amb { die 'poison dart' },
-        {'slowly'},
-        {'quickly'},
-        { die 'fire' };
+(sub ($w1, $w2, $w3, $w4){
+  # return if the values are false
+  return unless [and] test($w1, $w2), test($w2, $w3),test($w3, $w4);
+  # say the results. If there is one more Container layer around them this doesn't work, this is why we need the arguments here.
+  say "$w1 $w2 $w3 $w4"
+})(|@a); # supply the array as argumetns

Task/Amb/Perl-6/amb-2.pl6

@@ -1,22 +1,18 @@
-sub amb($var,*@a) {
-    "[{
-        @a.pick(*).map: {"||\{ $var = '$_' }"}
-     }]";
+sub infix:<lf> ($a,$b) {
+    next unless try $a.substr(*-1,1) eq $b.substr(0,1);
+    "$a $b";
 }
 
-sub joins ($word1, $word2) {
-    substr($word1,*-1,1) eq substr($word2,0,1)
-}
+multi dethunk(Callable $x) { try take $x() }
+multi dethunk(     Any $x) {     take $x   }
 
-'' ~~ m/
-    :my ($a,$b,$c,$d);
-    <{ amb '$a', <the that a> }>
-    <{ amb '$b', <frog elephant thing> }>
-    <?{ joins $a, $b }>
-    <{ amb '$c', <walked treaded grows> }>
-    <?{ joins $b, $c }>
-    <{ amb '$d', <slowly quickly> }>
-    <?{ joins $c, $d }>
-    { say "$a $b $c $d" }
-    <!>
-/;
+sub amb (*@c) { gather @c».&dethunk }
+
+say first *, do
+    amb(<the that a>, { die 'oops'}) Xlf
+    amb('frog',{'elephant'},'thing') Xlf
+    amb(<walked treaded grows>)      Xlf
+    amb { die 'poison dart' },
+        {'slowly'},
+        {'quickly'},
+        { die 'fire' };

Task/Amb/Perl-6/amb-3.pl6

@@ -0,0 +1,22 @@
+sub amb($var,*@a) {
+    "[{
+        @a.pick(*).map: {"||\{ $var = '$_' }"}
+     }]";
+}
+
+sub joins ($word1, $word2) {
+    substr($word1,*-1,1) eq substr($word2,0,1)
+}
+
+'' ~~ m/
+    :my ($a,$b,$c,$d);
+    <{ amb '$a', <the that a> }>
+    <{ amb '$b', <frog elephant thing> }>
+    <?{ joins $a, $b }>
+    <{ amb '$c', <walked treaded grows> }>
+    <?{ joins $b, $c }>
+    <{ amb '$d', <slowly quickly> }>
+    <?{ joins $c, $d }>
+    { say "$a $b $c $d" }
+    <!>
+/;