dynamic_grammar.rb in sequitur-0.1.19

- old
+ new
@@ -1,101 +1,97 @@
 require_relative 'production'
 require_relative 'grammar_visitor'
 
 module Sequitur # Module for classes implementing the Sequitur algorithm
-# A dynamic grammar is a context-free grammar that can be built incrementally.
-#   Formally, a grammar has:
-#   One start production
-#   Zero or more other productions
-#   Each production has a rhs that is a sequence of grammar symbols.
-#   Grammar symbols are categorized into
-#   -terminal symbols (i.e. String, Ruby Symbol,...)
-#   -non-terminal symbols (i.e. ProductionRef)
-class DynamicGrammar
-  # Link to the start production.
-  attr_reader(:start)
+  # A dynamic grammar is a context-free grammar that can be built incrementally.
+  #   Formally, a grammar has:
+  #   One start production
+  #   Zero or more other productions
+  #   Each production has a rhs that is a sequence of grammar symbols.
+  #   Grammar symbols are categorized into
+  #   -terminal symbols (i.e. String, Ruby Symbol,...)
+  #   -non-terminal symbols (i.e. ProductionRef)
+  class DynamicGrammar
+    # Link to the start production.
+    attr_reader(:start)
 
-  # The set of production rules of the grammar
-  attr_reader(:productions)
+    # The set of production rules of the grammar
+    attr_reader(:productions)
 
-  # nodoc Trace the execution of the algorithm.
-  attr(:trace)
+    # nodoc Trace the execution of the algorithm.
+    attr(:trace)
 
+    # Constructor.
+    # Build a grammar with one empty rule as start/start rule.
+    def initialize
+      @start = Production.new
+      @productions = [start]
+      @trace = false
+    end
 
-  # Constructor.
-  # Build a grammar with one empty rule as start/start rule.
-  def initialize()
-    @start = Production.new
-    @productions = [ start ]
-    @trace = false
-  end
+    # Emit a text representation of the grammar.
+    # Each production rule is emitted per line.
+    # @return [String]
+    def to_string
+      rule_text = productions.map(&:to_string).join("\n")
+      return rule_text
+    end
 
-  # Emit a text representation of the grammar.
-  # Each production rule is emitted per line.
-  # @return [String]
-  def to_string()
-    rule_text = productions.map(&:to_string).join("\n")
-    return rule_text
-  end
+    # Add a given production to the grammar.
+    # @param aProduction [Production]
+    def add_production(aProduction)
+      # TODO: remove output
+      puts "Adding #{aProduction.object_id}" if trace
+      puts aProduction.to_string if trace
+      productions << aProduction
+    end
 
+    # Remove a production with given index from the grammar
+    # @param anIndex [Fixnum]
+    # @return [Production] the production removed from the grammar.
+    def remove_production(anIndex)
+      puts "Before production removal #{productions[anIndex].object_id}" if trace
+      puts to_string if trace
+      prod = productions.delete_at(anIndex)
+      # TODO: remove output
+      puts('Removed: ' + prod.to_string) if trace
+      prod.clear_rhs
 
-  # Add a given production to the grammar.
-  # @param aProduction [Production]
-  def add_production(aProduction)
-    # TODO: remove output
-    puts "Adding #{aProduction.object_id}" if trace
-    puts aProduction.to_string if trace
-    productions << aProduction
-  end
+      return prod
+    end
 
+    # Add the given token to the grammar.
+    #   Append the token to the rhs of the start/start rule.
+    # @param aToken [Object] input token to add
+    def add_token(aToken)
+      append_symbol_to(start, aToken)
+    end
 
-  # Remove a production with given index from the grammar
-  # @param anIndex [Fixnum]
-  # @return [Production] the production removed from the grammar.
-  def remove_production(anIndex)
-    puts "Before production removal #{productions[anIndex].object_id}" if trace
-    puts to_string if trace
-    prod = productions.delete_at(anIndex)
-    # TODO: remove output
-    puts('Removed: ' + prod.to_string) if trace
-    prod.clear_rhs
+    # Part of the 'visitee' role in the Visitor design pattern.
+    #   A visitee is expected to accept the visit from a visitor object
+    # @param aVisitor [GrammarVisitor] the visitor object
+    def accept(aVisitor)
+      aVisitor.start_visit_grammar(self)
 
-    return prod
-  end
+      # Let's proceed with the visit of productions
+      productions.each { |prod| prod.accept(aVisitor) }
 
+      aVisitor.end_visit_grammar(self)
+    end
 
-  # Add the given token to the grammar.
-  #   Append the token to the rhs of the start/start rule.
-  # @param aToken [Object] input token to add
-  def add_token(aToken)
-    append_symbol_to(start, aToken)
-  end
+    # Factory method. Returns a visitor for this grammar.
+    # @return [GrammarVisitor]
+    def visitor
+      return GrammarVisitor.new(self)
+    end
 
-  # Part of the 'visitee' role in the Visitor design pattern.
-  #   A visitee is expected to accept the visit from a visitor object
-  # @param aVisitor [GrammarVisitor] the visitor object
-  def accept(aVisitor)
-    aVisitor.start_visit_grammar(self)
+    protected
 
-    # Let's proceed with the visit of productions
-    productions.each { |prod| prod.accept(aVisitor) }
-
-    aVisitor.end_visit_grammar(self)
-  end
-
-  # Factory method. Returns a visitor for this grammar.
-  # @return [GrammarVisitor]
-  def visitor()
-    return GrammarVisitor.new(self)
-  end
-
-  protected
-
-  # Append a given symbol to the rhs of passed production.
-  # @param aProduction [Production]
-  # @param aSymbol [Object]
-  def append_symbol_to(aProduction, aSymbol)
-    aProduction.append_symbol(aSymbol)
-  end
-end # class
+    # Append a given symbol to the rhs of passed production.
+    # @param aProduction [Production]
+    # @param aSymbol [Object]
+    def append_symbol_to(aProduction, aSymbol)
+      aProduction.append_symbol(aSymbol)
+    end
+  end # class
 end # module
 # End of file