- Extended the Hash.delete() method to detele more than one key a time.

new file:   scripts/topological_sort.sf

MANIFEST

@@ -859,6 +859,7 @@ scripts/sysopen_and_sysread.sf
 scripts/tennis_tournament.sf
 scripts/test_all.pl
 scripts/token_recursive.sf
+scripts/topological_sort.sf
 scripts/triangle_path.sf
 scripts/trizen's_pair_numbers.sf
 scripts/two_dimensional_array.sf

lib/Sidef/Types/Hash/Hash.pm

@@ -136,11 +136,8 @@ package Sidef::Types::Hash::Hash {
     *add = \&append;
 
     sub delete {
-        my ($self, $key) = @_;
-        if (exists $self->{data}{$key}) {
-            return (delete $self->{data}{$key})->get_value;
-        }
-        return;
+        my ($self, @keys) = @_;
+        Sidef::Types::Array::List->new(delete @{$self->{data}}{map { $_->get_value } @keys});
     }
 
     sub _iterate {

scripts/topological_sort.sf

@@ -0,0 +1,48 @@
+#!/usr/bin/ruby
+
+#
+## http://rosettacode.org/wiki/Topological_sort
+#
+
+func print_topo_sort (deps) {
+    var ba = Hash.new;
+    deps.each { |before, afters|
+        afters.each { |after|
+            if (before != after) {
+                ba[before][after] = 1;
+            };
+            ba[after] \\= Hash.new;
+        }
+    };
+
+    loop {
+        var afters = ba.keys.grep { ba[_].values.len == 0 }.sort;
+        afters.len || break;
+        say afters.join(" ");
+        ba.delete(afters...);
+        ba.values.each { |v| v.delete(afters...) };
+    };
+
+    say (ba.len ? "Cicle found! #{ba.keys.sort}" : "---");
+}
+
+var deps = Hash.new(
+    des_system_lib => < std synopsys std_cell_lib des_system_lib dw02
+                                                     dw01 ramlib ieee >,
+    dw01           => < ieee dw01 dware gtech                         >,
+    dw02           => < ieee dw02 dware                               >,
+    dw03           => < std synopsys dware dw03 dw02 dw01 ieee gtech  >,
+    dw04           => < dw04 ieee dw01 dware gtech                    >,
+    dw05           => < dw05 ieee dware                               >,
+    dw06           => < dw06 ieee dware                               >,
+    dw07           => < ieee dware                                    >,
+    dware          => < ieee dware                                    >,
+    gtech          => < ieee gtech                                    >,
+    ramlib         => < std ieee                                      >,
+    std_cell_lib   => < ieee std_cell_lib                             >,
+    synopsys       => <                                               >
+);
+
+print_topo_sort(deps);
+deps[:dw01].append('dw04');     # Add unresolvable dependency
+print_topo_sort(deps);