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module Grammar
class T
attr_accessor :word
def initialize word
@word = word
end
def to_s
"T<#{@word}>"
end
end
class NT
attr_accessor :symbol, :index, :left, :right
def initialize symbol=nil, index=nil, left=nil, right=nil
@symbol = symbol
@index = index
@left = left
@right = right
end
def from_s s
s.delete! '[]'
@symbol, meta = s.split '@'
if meta
span, index = meta.split ','
@left, @right = span.split(':').map { |x| x.to_i }
@index = index.to_i
end
end
def self.from_s s
n = NT.new
n.from_s s
return n
end
def to_s
"NT(#{@left},#{@right})<#{@symbol},#{@index}>"
end
end
class Rule
attr_accessor :lhs, :rhs, :target, :map
def initialize lhs=nil, rhs=[], target=[]
@lhs = lhs
@rhs = rhs
@target = target
@arity_ = nil
end
def to_s
"#{@lhs} -> #{@rhs.map{ |i| i.to_s }.join ' '} ||| #{@target.map{ |i| i.to_s }.join ' '} [arity=#{arity}]" #FIXME
end
def arity
return @arity_ if @arity_
rhs.select { |i| i.class == NT }.size
end
def read_right_ s
_ = []
s.split.each { |x|
x.strip!
if x[0]=='[' && x[x.size-1] == ']'
_ << NT.from_s(x)
else
_ << T.new(x)
end
}
return _
end
def from_s s
lhs, rhs, target = splitpipe s, 3
@lhs = NT.from_s lhs
@rhs = read_right_ rhs
@target = read_right_ target
end
def self.from_s s
r = self.new
r.from_s s
return r
end
end
class Grammar
attr_accessor :rules, :startn, :startt, :flat
def initialize fn
@rules = []; @startn = []; @startt = []; @flat = []
ReadFile.readlines_strip(fn).each_with_index { |s,i|
STDERR.write '.'; STDERR.write " #{i+1}\n" if (i+1)%80==0
@rules << Rule.from_s(s)
if @rules.last.rhs.first.class == NT
@startn << @rules.last
else
if rules.last.arity == 0
@flat << @rules.last
else
@startt << @rules.last
end
end
}
STDERR.write "\n"
end
def to_s
s = ''
@rules.each { |r| s += r.to_s+"\n" }
return s
end
def add_glue_rules
@rules.map { |r| r.lhs.symbol }.select { |s| s != 'S' }.uniq.each { |symbol|
@rules << Rule.new(NT.new('S'), [NT.new(symbol)])
@startn << @rules.last
@rules << Rule.new(NT.new('S'), [NT.new('S'), NT.new('X')])
@startn << @rules.last
}
end
def add_pass_through_rules s
s.each { |word|
@rules << Rule.new(NT.new('X'), [T.new(word)])
@flat << @rules.last
}
end
end
end # module
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