lib/activefacts/support.rb in activefacts-0.7.2 vs lib/activefacts/support.rb in activefacts-0.7.3

@@ -7,24 +7,31 @@
 #
 #module ActiveFacts
   $debug_indent = nil
   $debug_nested = false
   $debug_keys = nil
+  $debug_available = {}
   def debug(*args, &block)
     unless $debug_indent
       # First time, initialise the tracing environment
       $debug_indent = 0
       $debug_keys = {}
       if (e = ENV["DEBUG"])
         e.split(/[^a-zA-Z0-9]/).each{|k| $debug_keys[k.to_sym] = true }
+        if $debug_keys[:help]
+          at_exit {
+            $stderr.puts "---\nDebugging keys available: #{$debug_available.keys.map{|s| s.to_s}.sort*", "}"
+          }
+        end
       end
     end
 
     # Figure out whether this trace is enabled and nests:
     control = (!args.empty? && Symbol === args[0]) ? args.shift : :all
-    key = control.to_s.sub(/_\Z/, '')
-    enabled = $debug_nested || $debug_keys[key.to_sym]
+    key = control.to_s.sub(/_\Z/, '').to_sym
+    $debug_available[key] ||= key
+    enabled = $debug_nested || $debug_keys[key]
     nesting = control.to_s =~ /_\Z/
     old_nested = $debug_nested
     $debug_nested = nesting
 
     # Emit the message if enabled or a parent is:
@@ -53,7 +60,38 @@
       h[e] += 1
       h
     end.reject do |k,v|
       v == 1
     end.keys
+  end
+
+  # Allow indexing using a custom comparator:
+  def index value, &compare_block
+    compare_block ||= lambda{|a,b| a == b}
+    (0...size).detect{|i| compare_block[value, self[i]] }
+  end
+
+  # If any element, or sequence of elements, repeats immediately, delete the repetition.
+  # Note that this doesn't remove all re-occurrences of a subsequence, only consecutive ones.
+  # The compare_block allows a custom equality comparison.
+  def elide_repeated_subsequences &compare_block
+    compare_block ||= lambda{|a,b| a == b}
+    i = 0
+    while i < size  # Need to re-evaluate size on each loop - the array shrinks.
+      j = i
+      #puts "Looking for repetitions of #{self[i]}@[#{i}]"
+      while tail = self[j+1..-1] and k = tail.index(self[i], &compare_block)
+        length = j+1+k-i
+        #puts "Found at #{j+1+k} (subsequence of length #{j+1+k-i}), will need to repeat to #{j+k+length}"
+        if j+k+1+length <= size && compare_block[self[i, length], self[j+k+1, length]]
+          #puts "Subsequence from #{i}..#{j+k} repeats immediately at #{j+k+1}..#{j+k+length}"
+          slice!(j+k+1, length)
+          j = i
+        else
+          j += k+1
+        end
+      end
+      i += 1
+    end
+    self
   end
 end