1 files changed, 176 insertions, 0 deletions
diff --git a/intersect2.rb b/intersect2.rb
new file mode 100644
index 0000000..0d82c1d
--- /dev/null
+++ b/intersect2.rb
@@ -0,0 +1,176 @@
+#!/usr/bin/env ruby
+
+require_relative './grammar.rb'
+STDOUT.sync = true
+
+
+class Chart
+
+  def initialize n
+    @m = []
+    (n+1).times {
+      _ = []
+      (n+1).times { _ << [] }
+      @m << _
+    }
+    @b = {}
+  end
+
+  def at i, j
+    @m[i][j]
+  end
+
+  def add i, j, item
+    at(i,j) << item
+    @b["#{i},#{j},#{item.lhs.symbol}"] = true
+  end
+
+  def has symbol, i, j
+    return @b["#{i},#{j},#{symbol}"]
+  end
+end
+
+class Span
+  attr_accessor :left, :right
+
+  def initialize left=nil, right=nil
+    @left = left
+    @right = right
+  end
+end
+
+class Item < Rule
+  attr_accessor :lhs, :rhs, :span, :dot
+
+  def initialize rule_or_item, left, right, dot
+    @lhs = rule_or_item.lhs
+    @rhs = rule_or_item.rhs.dup
+    @span = Span.new left, right
+    @dot = dot
+  end
+
+  def to_s
+    "#{lhs} -> #{rhs.map{|i|i.to_s}.insert(@dot,'*').join ' '} [dot@#{@dot}] [arity=#{arity}] (#{@span.left}, #{@span.right})"
+  end
+end
+
+def init input, n, active_chart, passive_chart, grammar
+  grammar.flat.each { |r|
+    input.each_index { |i|
+      if input[i, r.rhs.size] == r.rhs.map { |x| x.word }
+        new_item = Item.new r, i, i+r.rhs.size, r.rhs.size
+        passive_chart.add i, i+r.rhs.size, new_item
+      end
+    }
+  }
+end
+
+def scan item, input, limit, passive_chart
+  while item.rhs[item.dot].class == T && item.span.right < limit
+    if item.rhs[item.dot].word == input[item.span.right]
+      item.dot += 1
+      item.span.right += 1
+    else
+      break
+    end
+  end
+end
+
+def parse input, n, active_chart, passive_chart, grammar
+  2.upto(n) { |span| # outer loop
+    0.upto(n-span) { |k|
+
+      puts " span(#{k},#{k+span})"
+
+      # try to apply rules starting with T
+      grammar.mixed.select { |r| r.rhs.first.word == input[k] }.each { |r|
+        new_item = Item.new r, k, k, 0
+        scan new_item, input, k+span, passive_chart
+        active_chart.at(k,k+span) << new_item
+      }
+
+      # seed active chart
+      grammar.rewrite.each { |r|
+        next if r.rhs.size > span
+        active_chart.at(k,k+span) << Item.new(r, k, k, 0)
+      }
+
+      active_chart.at(k,k+span).each { |active_item|
+        next if active_item.rhs[active_item.dot].class==T
+        # inner loop
+        1.upto(span-1) { |span2|
+          k.upto((k+span)-span2) { |l|
+
+            if passive_chart.has active_item.rhs[active_item.dot].symbol, l, l+span2
+              if l == active_item.span.right
+                new_item = Item.new active_item, active_item.span.left, l+span2, active_item.dot+1
+                scan new_item, input, k+span, passive_chart
+                if new_item.dot == new_item.rhs.size # done with item
+                  if new_item.span.left == k && new_item.span.right == k+span
+                    passive_chart.add k, k+span, new_item
+                  end
+                else
+                  if new_item.rhs[new_item.dot].class == NT && new_item.span.right+(new_item.rhs.size-(new_item.dot)) <= k+span
+                    active_chart.at(k,k+span) << new_item
+                  end
+                end
+              end
+            end
+          }
+        }
+      }
+
+      # 'self-filling' step
+      passive_chart.at(k,k+span).each { |passive_item|
+        active_chart.at(k,k+span).each { |active_item|
+          next if active_item.rhs[active_item.dot].class!=NT
+          if passive_item.lhs.symbol == active_item.rhs[active_item.dot].symbol
+            next if not active_item.span.right==passive_item.span.left
+            new_item = Item.new active_item, active_item.span.left, passive_item.span.right, active_item.dot+1
+            scan new_item, input, k+span, passive_chart
+            if new_item.dot == new_item.rhs.size
+              if new_item.span.left == k && new_item.span.right == k+span
+                passive_chart.add k, k+span, new_item
+              else
+                puts "#{new_item}" # FIXME never happens
+              end
+            else
+              if new_item.rhs[new_item.dot].class == NT && new_item.span.right+(new_item.rhs.size-(new_item.dot)) <= k+span
+                puts "NA@#{k},#{k+span} #{new_item}"
+                active_chart.at(k,k+span) << new_item
+              end
+            end
+          end
+        }
+      }
+    }
+  }
+end
+
+def visit n, depth, skip=0 # FIXME
+  (depth-skip).times { |i|
+    i += skip
+    0.upto(n-(i+1)) { |j|
+      yield j, j+i+1
+    }
+  }
+end
+
+def main
+  #input = 'ich sah ein kleines haus'.split
+  input = 'lebensmittel schuld an europäischer inflation'.split
+  #input = 'offizielle prognosen sind von nur 3 prozent ausgegangen , meldete bloomberg .'.split
+  n = input.size
+  grammar = Grammar.new 'example/grammar.x'
+  grammar.add_glue_rules
+  passive_chart = Chart.new n
+  active_chart = Chart.new n
+  init input, n, active_chart, passive_chart, grammar
+  parse input, n, active_chart, passive_chart, grammar
+  puts "---\npassive chart"
+  visit(n, n, 0) { |i,j| puts "#{i},#{j}"; passive_chart.at(i,j).each { |item| puts ' '+item.to_s }; puts }
+end
+
+
+main
+