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Contents
require 'journey/nfa/transition_table'
require 'journey/gtg/transition_table'
module Journey
module NFA
class Visitor < Visitors::Visitor
def initialize tt
@tt = tt
@i = -1
end
def visit_CAT node
left = visit node.left
right = visit node.right
@tt.merge left.last, right.first
[left.first, right.last]
end
def visit_GROUP node
from = @i += 1
left = visit node.left
to = @i += 1
@tt.accepting = to
@tt[from, left.first] = nil
@tt[left.last, to] = nil
@tt[from, to] = nil
[from, to]
end
def visit_OR node
from = @i += 1
children = node.children.map { |c| visit c }
to = @i += 1
children.each do |child|
@tt[from, child.first] = nil
@tt[child.last, to] = nil
end
@tt.accepting = to
[from, to]
end
def terminal node
from_i = @i += 1 # new state
to_i = @i += 1 # new state
@tt[from_i, to_i] = node
@tt.accepting = to_i
@tt.add_memo to_i, node.memo
[from_i, to_i]
end
end
class Builder
def initialize ast
@ast = ast
end
def transition_table
tt = TransitionTable.new
Visitor.new(tt).accept @ast
tt
end
end
end
end
Version data entries
104 entries across 78 versions & 19 rubygems