From d9fbb2c4900b008daa9c5e0302677f9d1674a473 Mon Sep 17 00:00:00 2001
From: Nathan Lasseter <nathan@4574.co.uk>
Date: Sat, 29 Mar 2014 16:23:06 +0000
Subject: Begun modularising

---
 lib/ndfa.rb | 146 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 lib/node.rb |  44 ++++++++++++++++++
 lib/vfsm.rb |   2 +
 3 files changed, 192 insertions(+)
 create mode 100644 lib/ndfa.rb
 create mode 100644 lib/node.rb
 create mode 100644 lib/vfsm.rb

(limited to 'lib')

diff --git a/lib/ndfa.rb b/lib/ndfa.rb
new file mode 100644
index 0000000..2e610cf
--- /dev/null
+++ b/lib/ndfa.rb
@@ -0,0 +1,146 @@
+module VFSM
+	class NDFA
+		attr_reader :currentnodes
+
+		def initialize(machineDefinition)
+			inedges = false
+			nodes = []
+			@currentnodes = []
+
+			lineno = 0
+			File.foreach(machineDefinition) do |line|
+				lineno += 1
+				linearray = line.chomp.split
+				unless inedges then
+					if linearray == [] then
+						#do nothing
+					elsif linearray[0].downcase == "comment:" then
+						#do nothing
+					elsif linearray[0].downcase == "nodes:" then
+						#do nothing
+						#ignore line for backwards compatability
+					elsif linearray[0].downcase == "start:" then
+						tempsnode = nodes.select do |node|
+							node.id == linearray[1]
+						end
+						if tempsnode.length == 0 then
+							startnode = Node.new linearray[1]
+							nodes.push startnode
+							@currentnodes.push startnode
+						else
+							@currentnodes.push tempsnode[0]
+						end
+					elsif linearray[0].downcase == "accept:" then
+						linearray[1..-1].each do |node|
+							anodes = nodes.select do |inode|
+								node == inode.id
+							end
+							if anodes.length == 0 then
+								mynode = Node.new node, true
+								nodes.push mynode
+							else
+								anodes[0].accepting!
+							end
+						end
+					elsif linearray[0].downcase == "edges:" then
+						inedges = true
+					else
+						puts "Syntax error at line #{lineno}"
+						puts line
+						exit
+					end
+				else
+					if linearray[0].downcase == "end:" then
+						inedges = false
+					else
+						fnode = nil
+						tnode = nil
+						fnodes = nodes.select do |node|
+							node.id == linearray[0]
+						end
+						if fnodes.length == 0 then
+							fnode = Node.new linearray[0]
+							nodes.push fnode
+						else
+							fnode = fnodes[0]
+						end
+						tnodes = nodes.select do |node|
+							node.id == linearray[2]
+						end
+						if tnodes.length == 0 then
+							tnode = Node.new linearray[2]
+							nodes.push tnode
+						else
+							tnode = tnodes[0]
+						end
+						if linearray[1].downcase == "epsilon:" or linearray[1].downcase == "lambda:" then
+							fnode.pushedge :lambda, tnode
+						else
+							fnode.pushedge linearray[1], tnode
+						end
+					end
+				end
+			end
+			NDFA.recurse @currentnodes
+			NDFA.printnodes @currentnodes
+		end
+
+		def handleinput(inputString)
+			inputString.chomp.split.each do |input|
+				nextnodes = []
+				@currentnodes.each do |node|
+					nextnode = node.goto input
+					unless nextnode == :reject
+						nextnode.each do |x|
+							nextnodes.push x
+						end
+					end
+				end
+
+				NDFA.recurse nextnodes
+
+				print " --#{input}--> "
+
+				NDFA.printnodes nextnodes
+
+				if nextnodes == [] then
+					puts
+					puts "Invalid input, REJECTED"
+					exit
+				else
+					@currentnodes = nextnodes
+				end
+			end
+		end
+
+		class << self
+			def printnodes nodes
+				print "{ "
+				(0..(nodes.length - 1)).each do |x|
+					if nodes[x].accepting? then
+						print "((#{nodes[x].id}))"
+					else
+						print "(#{nodes[x].id})"
+					end
+					print ", " unless x == (nodes.length - 1)
+				end
+				print " }"
+			end
+
+			def recurse nodeslist
+				begin
+					oldlist = nodeslist.dup
+					oldlist.each do |node|
+						tmp = node.goto :lambda
+						unless tmp == :reject then
+							tmp.each do |x|
+								nodeslist.push x
+							end
+						end
+					end
+					nodeslist.uniq!
+				end while oldlist != nodeslist
+			end
+		end
+	end
+end
diff --git a/lib/node.rb b/lib/node.rb
new file mode 100644
index 0000000..5875e38
--- /dev/null
+++ b/lib/node.rb
@@ -0,0 +1,44 @@
+module VFSM
+	class Node
+		def initialize id, accepting = false
+			@id = id
+			@accepting = accepting
+			@edges = []
+		end
+
+		def id
+			return @id
+		end
+
+		def accepting! accepting=true
+			@accepting = accepting
+		end
+
+		def accepting?
+			return @accepting
+		end
+
+		def pushedge on, to
+			tempto = @edges.select do |edge|
+				edge[0] == on
+			end
+			@edges.push [on, to]
+		end
+
+		def goto on
+			to = @edges.select do |edge|
+				edge[0] == on
+			end
+
+			if to.length == 0 then
+				return :reject
+			else
+				ret = []
+				to.each do |x|
+					ret.push x[1]
+				end
+				return ret
+			end
+		end
+	end
+end
diff --git a/lib/vfsm.rb b/lib/vfsm.rb
new file mode 100644
index 0000000..6c5ff96
--- /dev/null
+++ b/lib/vfsm.rb
@@ -0,0 +1,2 @@
+require './lib/node'
+require './lib/ndfa'
-- 
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