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#!/usr/bin/env ruby
require_relative './grammar.rb'
STDOUT.sync = true
class Chart
def initialize n
@m = []
(n+1).times {
_ = []
(n+1).times { _ << [] }
@m << _
}
end
def at i, j
@m[i][j]
end
def add rule_or_item, i, j, right, dot=0
item = Item.new(rule_or_item)
item.span.left = i
item.span.right = right
item.dot = dot
at(i, j) << item
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
@lhs = rule_or_item.lhs.dup
@rhs = rule_or_item.rhs.dup
if rule_or_item.class == Item
@span = Span.new rule_or_item.span.left, rule_or_item.span.right
@dot = rule_or_item.dot
else
@span = Span.new
@dot = 0
end
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 visit n, depth, skip=0
(depth-skip).times { |i|
i += skip
0.upto(n-(i+1)) { |j|
yield j, j+i+1
}
}
end
def init active_chart, passive_chart, grammar, input, n
# pre-fill passive chart w/ 0-arity rules
grammar.rules.select { |r| r.rhs.first.class==T }.each { |r|
input.each_index.select { |i| input[i].word==r.rhs.first.word }.each { |j|
k = 1
if r.rhs.size > 1
z = r.rhs.index { |i| i.class==NT }
if z
z -= 1
else
z = r.rhs.size-1
end
if input[j..j+z].map { |i| i.word } == r.rhs[0..z].map { |i| i.word }
k = z+1
else
next
end
end
if k == r.rhs.size
passive_chart.add(r, j, j+k, j+k, k)
else
(j+k).upto(n) { |l| active_chart.add r, j, l, j+k, k }
end
}
}
# seed active chart
s = grammar.rules.reject { |r| r.rhs.first.class!=NT }
visit(n, n, 1) { |i,j|
s.each { |r| active_chart.add(r, i, j, i) }
}
end
def scan item, passive_chart, input
while item.rhs[item.dot].class == T
break if item.span.right > input.size-1
if item.rhs[item.dot].word == input[item.span.right].word
item.dot += 1
item.span.right += 1
break if item.dot == item.rhs.size
else
break
end
end
end
def parse i, j, n, active_chart, passive_chart, input
active_chart.at(i,j).each { |active_item|
1.upto(n) { |span|
break if span==(j-i)
i.upto(j-span) { |k|
passive_chart.at(k, k+span).each { |passive_item|
if active_item.rhs[active_item.dot].class==NT && 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
new_item.span.right = passive_item.span.right
new_item.dot += 1
scan new_item, passive_chart, input
if new_item.dot == new_item.rhs.size
passive_chart.at(i,j) << new_item if new_item.span.left==i&&new_item.span.right==j
else
# item is dead unless it has an NT to fill
active_chart.at(i,j) << new_item if new_item.span.left==i&&new_item.rhs[new_item.dot].class==NT
end
end
}
}
}
true
}
# self-filling
to_add_active = []
to_add_passive = []
passive_chart.at(i,j).each { |passive_item|
active_chart.at(i,j).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
new_item.span.right = passive_item.span.right
new_item.dot += 1
scan new_item, passive_chart, input
if new_item.dot == new_item.rhs.size
to_add_passive << new_item if new_item.span.left==i&&new_item.span.right==j
else
to_add_active << new_item
end
end
}
}
to_add_active.each { |item| active_chart.at(i,j) << item }
to_add_passive.each { |item| passive_chart.at(i,j) << item }
end
def preprocess s
s.split.map { |i| T.new i }
end
def main
#input = preprocess 'ich sah ein kleines haus'
input = preprocess 'lebensmittel schuld an europäischer inflation'
#input = preprocess 'offizielle prognosen sind von nur 3 prozent ausgegangen , meldete bloomberg .'
n = input.size
puts 'reading grammar'
#g = Grammar.new 'example/grammar'
g = Grammar.new 'example/grammar.x'
#g = Grammar.new 'example/grammar.3.gz' # 4th segment of newstest2008
puts 'adding glue rules'
g.add_glue_rules
#puts 'adding pass-through rules'
#g.add_pass_through_rules input
puts 'initializing charts'
passive_chart = Chart.new n
active_chart = Chart.new n
init active_chart, passive_chart, g, input, n
puts 'parsing'
visit(n, n, 1) { |i,j|
STDERR.write " span (#{i}, #{j})\n"
parse i, j, n, active_chart, passive_chart, input
}
puts "---\npassive chart"
visit(n, n, 0) { |i,j| puts "#{i},#{j}"; passive_chart.at(i,j).each { |item| puts ' '+item.to_s if item.span.left==i&&item.span.right==j }; puts }
end
main
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