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|
#!/usr/bin/env ruby
require_relative './grammar.rb'
class Chart
attr_accessor :m
def initialize input
@m = []
(input.size+1).times {
_ = []
(input.size+1).times { _ << [] }
@m << _
}
end
def at i,j
return @m[i][j]
end
end
class Item < Rule
attr_accessor :lhs, :rhs, :span, :dot
def initialize rule, dot=-1
@lhs = rule.lhs.dup
@rhs = rule.rhs.dup
@span = Span.new rule.span.left, rule.span.right
@dot = dot
if rule.class==Item
@dot = rule.dot
end
end
def to_s
"#{lhs} -> #{rhs.map{|i|i.to_s}.insert(@dot,'*').join ' '} dot:#{@dot} a:#{arity} (#{@span.left}, #{@span.right})"
end
end
# set-up
g = Grammar.new 'grammar'
input = "ich sah ein kleines haus".split.map { |i| Terminal.new i }
passive_chart = Chart.new input
active_chart = Chart.new input
# pre-fill passive chart w/ arity-0 rules
g.rules.reject { |r| r.arity>0 }.each { |r|
input.each_index.select{ |j| input[j].w==r.rhs.first.w }.each { |j|
k = 1
if r.rhs.size > 1
slice = input[j,j+(r.rhs.size-1)].map { |i| i.w }
if slice == r.rhs.map { |i| i.w }
k = r.rhs.size
else
next
end
end
passive_chart.at(j,j+k) << Item.new(r)
passive_chart.at(j,j+k).last.span.left = j
passive_chart.at(j,j+k).last.span.right = j+k
passive_chart.at(j,j+k).last.dot = k
}
}
# pre-fill active chart with non 0arity rules starting with a (single(!)) T
g.rules.reject{|r| r.rhs[0].class==NonTerminal||r.arity==0}.each {|r|
input.each_with_index { |i,j|
if i.w==r.rhs.first.w
(j+2).upto(input.size) { |k| # no empty NT!
active_chart.at(j,k) << Item.new(r)
active_chart.at(j,k).last.span.left = j
active_chart.at(j,k).last.span.right = j+1
active_chart.at(j,k).last.dot = 1
}
end
}
}
# pre-fill active chart
s = g.rules.reject { |r| r.rhs.first.class!=NonTerminal}#.reject{|r| r.lhs.sym == 'S'}
(input.size).times { |k|
0.upto(input.size-(k+2)) { |i|
s.each { |r|
active_chart.at(i,i+k+2) << Item.new(r)
active_chart.at(i,i+k+2).last.span.left = i
active_chart.at(i,i+k+2).last.span.right = i
active_chart.at(i,i+k+2).last.dot = 0
}
}
}
# scan
def scan i, j, active_chart, passive_chart, input
active_chart.at(i,j).each { |item|
while item.rhs[item.dot].class == Terminal
if item.rhs[item.dot].w == input[item.span.left+item.dot].w
item.dot += 1
if item.dot == item.rhs.size
passive_chart.at(i,j) << Item.new(item)
passive_chart.at(i,j).last.span.right = item.span.left+item.dot
end
end
end
}
end
# parse
def visit i, j, sz, active_chart, passive_chart, g, input
puts "| #{i},#{j}"
# SCAN
scan i, j, active_chart, passive_chart, input
1.upto(sz) { |span|
break if span==(j-i)
i.upto(j-span) { |k|
puts " #{k},#{k+span} (##{span})"
# COMPLETE
active_chart.at(i,j).each { |active_item|
passive_chart.at(k, k+span).each { |passive_item|
if active_item.rhs[active_item.dot].class==NonTerminal && passive_item.lhs.sym == active_item.rhs[active_item.dot].sym
next if not active_item.span.right==passive_item.span.left
active_item.span.right = passive_item.span.right
active_item.dot += 1
if active_item.dot == active_item.rhs.size
passive_chart.at(i,j) << Item.new(active_item)
end
end
}
}
}
scan i, j, active_chart, passive_chart, input
}
end
# once for each cell
(input.size).times { |k|
0.upto(input.size-(k+2)) { |i|
visit i, i+k+2, input.size, active_chart, passive_chart, g, input
}
}
puts "---"
passive_chart.at(3,5).each { |item|
puts item.to_s
}
|
