How to use terminal method of NonTerminal Package

Best Rr_ruby code snippet using NonTerminal.terminal

parser-en.rb

Source:parser-en.rb

1# nonterminal-symbol2class NonTerminal3	attr_reader :name	   # String4	attr_accessor :rules	# Production rules for this symbol. Array of Arrays of Strings or other NonTerminal instances5	def initialize(n)6		@name = n7		@rules = []8	end9	def <<(r)10		@rules << r11	end12	def to_s13		"<" + @name + ">"14	end15	def inspect16		to_s17	end18end19# A parsed nonterminal symbol20class NTermInst21	attr_accessor :nonTerminal  # The accompanying NonTerminal instance22	attr_accessor :decision	 # Index of the production rule applied to get the parsing result ( =index of the child in the decision-tree)23	attr_accessor :children	 # Instances of the symbols produced after applying the production rule; Array of Strings and more NTermInst-Instances24	def initialize(nt)25		@nonTerminal = nt26		@decision = -127		@children = []28	end29	# Recursive textbased representation (Parser-Tree)30	def to_s(depth = 0)31		ind = "  " * depth32		ind + "[#{nonTerminal}/#{decision}" +33		if(children.size == 0)34			"]\n"35		else36			"\n" + children.map { |c| if(c.is_a?(String)) then ind + "  " + c.inspect + "\n" else c.to_s(depth+1) end }.join("") + ind + "]\n"37		end38	end39	def inspect40		to_s41	end42	# Search all child elements recursively which are instances of the nonterminal symbol contNT, collect all contained child elements43	# which are of type childclass and return them as an array. childclass can be a ruby-class or a NonTerminal instance.44	# Used to read in recursive grammar-definitions as a flat array45	def collectRecursive(contNT, childclass)46		@children.select { |c|47			(childclass.is_a?(Class) && c.is_a?(childclass)) ||48				(childclass.is_a?(NonTerminal) && c.is_a?(NTermInst) && c.nonTerminal == childclass) } +49			@children.select { |c| c.is_a?(NTermInst) && c.nonTerminal == contNT }.inject([]) { |old,obj| old+obj.collectRecursive(contNT, childclass) }50	end51	# Recursively collect all read in strings ( of Terminal symbols ) and return them as one ruby string52	# Used to get the textual representation of this instance in the parsed string53	def collectString54		@children.map { |c| if(c.is_a?(String)) then c else c.collectString end }.join("")55	end56	def [](ind)57		@children[ind]58	end59end60# Represents a branch in the decision-tree of the non-deterministic stack machine (NPDA). Is managed via a query to run a breadth first search61# on that tree.62class DNode63	attr_accessor :nonTerminal	  # The nonterminal symbol, whose rules are the subject of the decision of this node in the tree64	attr_accessor :index			# Currenty processed decision (index of the NonTerminal#rules Array)65	attr_accessor :strIndex		 # Index in input string66	attr_accessor :stack			# Stack at the point of the decision67	attr_accessor :pnode			# Previous(parent) branch68	attr_accessor :pindex		   # Decision that was made in the parent branch to reach this branch69	def initialize(n, i, s, si, pn)70		@nonTerminal = n71		@index = i72		@stack = s73		@strIndex = si74		@pnode = pn75		if(pn != nil)76			@pindex = pn.index77		end78	end79end80# Represents a grammar as ruby-objects. Hash of names of nonterminal symbols to the corresponding NonTerminal instances81class Grammar < Hash82	attr_accessor :start	# Start symbol (initial content of the stack)83	def initialize(nn,&block)84		nn.each { |n| self[n] = NonTerminal.new(n) }85		@start = nil86		if(block != nil) then block.call(self) end87	end88	# Parse string with this grammar. Returns nil in case of non-acceptance, else the root of the parser tree as a DNode-instance else89	def parse(str)90		queue = []		  # Queue of DNode-Instances, for the breadth first search in the decision tree91		stack = [start]	 # Stack of the NPDA92		index = 0		   # Position in the input string93#		debug "STACK #{stack}\n"94	   95		while(!stack.empty? || index != str.length)96			if(!stack.empty? && stack.last.is_a?(String) && (stack.last.length <= str.length-index) && str[index...index+stack.last.length] == stack.last)97				# Accept-away the string (advance)98				top = stack.pop99#				debug("Akzeptiere String #{top.inspect}\n")100				index += top.length101			elsif(!stack.empty? && stack.last.is_a?(NonTerminal) && stack.last.rules.size == 1)102				# Apply rule directly, no decision neccessary103				top = stack.pop104#				debug "#{top} : Direkt ersetzen -> #{top.rules[0]}\n"105				stack.concat(top.rules[0].reverse)106			else107				if(!stack.empty? && stack.last.is_a?(NonTerminal))108					# Queue decision109					top = stack.pop110#					debug "#{top} : Einreihen\n"111					queue.push(DNode.new(top, -1, stack, index, if(queue.empty?) then nil else queue.first end))112				else113					# Dead end - forget stack114				end115				# Apply nex dicision in the queue116				if(queue.empty? || (queue.first.index == queue.first.nonTerminal.rules.length - 1 && queue.size < 2))117					# Can't continue in the current path(branch), no other existing paths => Don't accept string118					return nil119				else120					decide = queue.first121					decide.index = decide.index+1122					# Last decision for this DNode-object; take the next from the queue123					if(decide.index == decide.nonTerminal.rules.length)124#						debug("#{queue.first.nonTerminal} : Dead end go to #{queue[1].nonTerminal}/#{queue[1].index+1}")125						queue.delete_at(0)126						decide = queue.first127						decide.index = decide.index+1128						129#						debug("#{decide.nonTerminal}: Last Decision")130					else131						# Next decision for this branch132#						debug "#{decide.nonTerminal}: Decide #{decide.index}"133					end134					# Use the stack of this branch135					stack = decide.stack.clone136#					debug " ++ #{decide.nonTerminal.rules[decide.index]}\n"137					# Decided -> Apply production rule (Fill stack)138					stack.concat(decide.nonTerminal.rules[decide.index].reverse)139					# Jump to the position of this branch in the input string140					index = decide.strIndex141				end142			end143#			debug "STACK #{stack}\n"144		end145		# Backtrace what decision was applied when, to generate array of indices of decisions (backwards)146		trace = []147		if(!queue.empty?)148			d = queue.first149			trace << d.index150			while(d.pnode != nil)151				trace << d.pindex152				d = d.pnode153			end154		end155	   156		# Generate parser tree157		root = NTermInst.new(start)158		stack = [root]159		while(!stack.empty?)160			top = stack.pop()161			# What decision was done here162			top.decision = if(top.nonTerminal.rules.size>1) then trace.pop() else 0 end163		   164			s = top.nonTerminal.rules[top.decision].size165			top.children = Array.new(s)166		   167			# For all symbols on the right side of this production rule...168			(s-1).downto(0) { |i|169				sym = top.nonTerminal.rules[top.decision][i]170				top.children[i] = if(sym.is_a?(String))171					# String ( = Sequence of terminal symbols) => Put into parser tree172					sym173				else174					# Non terminal symbols => to stack175					x = NTermInst.new(sym)176					stack.push(x)177					x178				end179			}180		end181	   182#		debug "Accepting\n"183		root # Parserbaum zurÃ¼ckgeben184	end185	# Return textual BNF of this grammar186	def to_s187		map { |k,v|188			v.to_s + " ::= " + v.rules.map { |r| r.map{|e| e.inspect}.join(" ") }.join(" | ")189		}.join("\n")190	end191	def inspect192		to_s193	end194#	def debug(str)195#	   $stdout.write(str)196#	end197	# Returns the Grammar of the modified BNF, which allows parsing arbitrary special chars198	def Grammar.BNF199		@@bnf ||= Grammar.new(["BNF", "BNF2", "Def", "Rules", "Rules2", "Rule", "Symbol", "String", "Chars", "Char", "NTerm", "Name", "Name2", "SpaceE", "Space", "Alpha", "Alnum"]) { |g|200			g["BNF"] <<  [g["Def"], g["BNF2"]]201			g["BNF2"].rules = [["\n", g["Def"], g["BNF2"]], [], ["\n", g["BNF2"]]]202			g["Def"] << [g["SpaceE"], g["NTerm"], g["SpaceE"], "::=", g["Rules"]]203			g["Rules"] << [g["Rule"], g["Rules2"]]204			g["Rules2"].rules= [["|", g["Rule"], g["Rules2"]], []]205			g["Rule"] << [g["SpaceE"]]206			g["Rule"] << [g["SpaceE"], g["Symbol"], g["Rule"]]207			g["Symbol"].rules = [[g["String"]], [g["NTerm"]]]208			g["String"] << ["\"", g["Chars"], "\""]209			g["Chars"] << []210			g["Chars"] << [g["Char"], g["Chars"]]211			for i in 0..255 do212				g["Char"] << [[i].pack("C").inspect[1..-2]]213			end214			g["NTerm"] << ["<", g["Name"], ">"]215			g["Name"] << [g["Alpha"]]216			g["Name"] << [g["Alpha"], g["Name2"]]217			g["Name2"] << [g["Alnum"], g["Name2"]]218			g["Name2"] << []219			g["SpaceE"] << [g["Space"]]220			g["SpaceE"] << []221			g["Space"] << [" ",  g["SpaceE"]]222			g["Space"] << ["\t", g["SpaceE"]]223			g["Space"] << ["\r", g["SpaceE"]]224			for i in 0..25 do225				a = [[[65 + i].pack("C")], [[97 + i].pack("C")]]226				g["Alpha"].rules.concat(a)227				g["Alnum"].rules.concat(a)228			end229			for i in 0..9 do230				g["Alnum"] << [[48 + i].pack("C")]231			end232			g.start = g["BNF"]233		}234	end235	# Parse given grammar in BNF and return as instance of 'Grammar'. Uses the grammar for BNF.236	def Grammar.fromBNF(str)237		b = Grammar.BNF238		s = nil239		defs = b.parse(str).collectRecursive(b["BNF2"], b["Def"])240		g = Grammar.new(defs.map { |df| df[1][1].collectString })241		defs.each { |df|242#		   puts "foobar"243			name = df[1][1].collectString244			nt = g[name]245			if(s == nil) then s = nt end		# Use the 1st defined Nonterminal symbol as start symbol246			nt.rules = df[4].collectRecursive(b["Rules2"], b["Rule"]).map { |rule|247				rule.collectRecursive(b["Rule"], b["Symbol"]).map { |sym|248					if(sym.decision == 0)249						eval(sym[0].collectString)250					else251						g[sym[0][1].collectString]252					end253				}254			}255		}256		g.start = s257		g258	end259end...

nullable.rb

Source:nullable.rb

1require 'core/semantics/factories/combinators'2require 'core/semantics/factories/obj-fold'3class Grammar4  attr_reader :start, :rules5  def initialize(start, rules)6    @start = start7    @rules = rules8  end9end10class Rule11  attr_reader :name, :alts12  def initialize(name, alts)13    @name = name14    @alts = alts15  end16end17class Alt18  attr_reader :elts19  def initialize(elts)20    @elts = elts21  end22end23class Sym24end25class NonTerminal < Sym26  attr_reader :name27  def initialize(name)28    super()29    @name = name30  end31end32class Terminal < Sym33  attr_reader :value34  def initialize(value)35    super()36    @value = value37  end38end39class Nullable40  include Factory41  def FindRule(sup)42    Class.new(sup) do 43      def find_rule(name)44        @@grammar.rules.find_first {|r| r.name == name}45      end46    end47  end48        49  def Grammar(sup)50    Class.new(FindRule(sup)) do51      def nullable?(tbl)52        @@grammar = self53        find_rule(start.name).nullable?(tbl)54      end55    end56  end57  58  def Rule(sup)59    Class.new(sup) do60      def nullable?(tbl)61        alts.inject(false) { |cur, alt| cur | alt.nullable?(tbl) }62      end63    end64  end65  def Alt(sup)66    Class.new(sup) do67      def nullable?(tbl)68        elts.inject(true){ |cur, elt| cur & elt.nullable?(tbl) }69      end70    end71  end72  def Terminal(sup)73    Class.new(sup) do 74      def nullable?(tbl)75        false76      end77    end78  end79  def NonTerminal(sup)80    Class.new(FindRule(sup)) do81      def nullable?(tbl)82        x = find_rule(name).nullable?(tbl)83        tbl[name] = x84      end85    end86  end87end88        89      90Arith = Grammar.new(NonTerminal.new(:Stat), 91                [92                 Rule.new(:Exp, [93                                 Alt.new([Terminal.new(:Var)]),94                                 Alt.new([NonTerminal.new(:Exp),95                                          Terminal.new("+"),96                                          NonTerminal.new(:Exp)])]),97                 Rule.new(:Stat, [Alt.new([NonTerminal.new(:Exp),98                                           Terminal.new(";")]),99                                  Alt.new([Terminal.new("{"),100                                           NonTerminal.new(:Stats),101                                           Terminal.new("}")])]),102                 Rule.new(:Stats, [Alt.new([]),103                                   Alt.new([NonTerminal.new(:Stat),104                                            NonTerminal.new(:Stats)])])105                ])106#FixNullable = RExtend.new(Fixpoint.new(:nullable?, true), Nullable.new, 107#                          {:NonTerminal => :Node})108#FixNullable = Extend.new(Rename.new(Fixpoint.new(:nullable?, true),109#                                    {:NonTerminal => :Node}),110#                          Nullable.new)111FixNullable = Extend.new(Restrict.new(Circular.new({:nullable? => false}),112                                  [:NonTerminal]), Nullable.new)113ArithNullableFix = FFold.new(FixNullable).fold(Arith)114tbl = {}115puts ArithNullableFix.nullable?(tbl)116p tbl      ...

visitor.rb

Source:visitor.rb

...17	ret.push(i.accept(self))18      end19      ret20    end21    def Visitor.define_visit_Nonterminal(element_type)22      eval <<-END_OF_EVAL23      def visit_#{element_type.id2name}(element)24	apply_to_#{element_type.id2name}(element, visit_children(element))25      end26      END_OF_EVAL27    end28    def Visitor.define_visit_Terminal(element_type)29      eval <<-END_OF_EVAL30      def visit_#{element_type.id2name}(element)31	apply_to_#{element_type.id2name}(element)32      end33      END_OF_EVAL34    end35    define_visit_Terminal(:Include)36    define_visit_Terminal(:Verbatim)37    define_visit_Terminal(:MethodListItemTerm)38    define_visit_Nonterminal(:DocumentElement)39    define_visit_Nonterminal(:Headline)40    define_visit_Nonterminal(:TextBlock)41    define_visit_Nonterminal(:ItemList)42    define_visit_Nonterminal(:EnumList)43    define_visit_Nonterminal(:DescList)44    define_visit_Nonterminal(:MethodList)45    define_visit_Nonterminal(:ItemListItem)46    define_visit_Nonterminal(:EnumListItem)47    48    def visit_DescListItem(element)49      term = element.term.accept(self)50      apply_to_DescListItem(element, term, visit_children(element))51    end52    define_visit_Nonterminal(:DescListItemTerm)53    def visit_MethodListItem(element)54      term = element.term.accept(self)55      apply_to_MethodListItem(element, term, visit_children(element))56    end57    define_visit_Terminal(:StringElement)58    define_visit_Terminal(:Verb)59    define_visit_Nonterminal(:Emphasis)60    define_visit_Nonterminal(:Code)61    define_visit_Nonterminal(:Var)62    define_visit_Nonterminal(:Keyboard)63    define_visit_Nonterminal(:Index)64    define_visit_Nonterminal(:Footnote)65    def visit_Reference(element)66      children = visit_children(element)67      begin68	element.result_of_apply_method_of(self, children)69      rescue NameError70	apply_to_Reference(element, children)71      end72    end73  end 74end ...

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