Class: RubyLexer::SymbolTable

Inherits:
Object
  • Object
show all
Defined in:
lib/rubylexer/symboltable.rb

Instance Method Summary collapse

Constructor Details

#initialize ⇒ SymbolTable

Returns a new instance of SymbolTable.



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# File 'lib/rubylexer/symboltable.rb', line 22

def initialize
   #note: below Stack means Array (used as a stack)
   @symbols={} #Hash of String to Stack of Object(user-defined)
   @locals_lists=[{}] #Stack of Hash of String to Boolean
end

Instance Method Details

#[](name) ⇒ Object Also known as: === 



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# File 'lib/rubylexer/symboltable.rb', line 74

def [](name)
   assert @locals_lists.last
   (stack=@symbols[name]) and stack.last
end

#[]=(name, val) ⇒ Object 



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# File 'lib/rubylexer/symboltable.rb', line 81

def []=(name, val)
   assert @locals_lists.last
   if @locals_lists.last and @locals_lists.last[name]
      #already defined in this block
      @symbols[name][-1]=val #overwrite current value
   else
      stack=(@symbols[name] ||= [])
      stack.push val
      @locals_lists.last[name]=true
   end
   assert @locals_lists.last
   return val
end

#__locals_lists ⇒ Object 



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# File 'lib/rubylexer/symboltable.rb', line 70

def __locals_lists
  @locals_lists
end

#deep_copy ⇒ Object 



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# File 'lib/rubylexer/symboltable.rb', line 45

def deep_copy
  result=SymbolTable.allocate
  new_symbols={}
  @symbols.each_pair{|str,stack|
    new_symbols[str.clone]=stack.map{|elem| elem.clone rescue elem }
  }
  new_locals_lists=[]
  @locals_lists.each{|hash|
    new_locals_lists.push({})
    hash.each_pair{|str,bool|
      new_locals_lists.last[str.dup]=bool
    }
  }
  new_locals_lists.push({}) if new_locals_lists.empty?
  result.instance_eval{
    @symbols=new_symbols
    @locals_lists=new_locals_lists
  }
  return result
end

#end_block ⇒ Object 



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# File 'lib/rubylexer/symboltable.rb', line 34

def end_block
   assert @locals_lists.last
   list=@locals_lists.pop
   list or raise "unbalanced end block"
   list.each_key {|sym|
      @symbols[sym].pop
      @symbols[sym].empty? and @symbols.delete sym
   }
   assert @locals_lists.last
end

#names ⇒ Object 



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# File 'lib/rubylexer/symboltable.rb', line 66

def names
  @symbols.keys
end

#start_block ⇒ Object 



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# File 'lib/rubylexer/symboltable.rb', line 28

def start_block
   assert @locals_lists.last
   @locals_lists.push({})
   assert @locals_lists.last
end