Class: ANTLR3::Rewrite::RewriteProgram

Inherits:
Object
  • Object
show all
Defined in:
lib/antlr3/streams/rewrite.rb

Instance Method Summary collapse

Constructor Details

#initialize(stream, name = nil) ⇒ RewriteProgram

Returns a new instance of RewriteProgram.



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# File 'lib/antlr3/streams/rewrite.rb', line 165

def initialize( stream, name = nil )
  @stream = stream
  @name = name
  @operations = []
end

Instance Method Details

#clear ⇒ Object 



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# File 'lib/antlr3/streams/rewrite.rb', line 296

def clear
  @operations.clear
end

#delete(*range_arguments) ⇒ Object 



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# File 'lib/antlr3/streams/rewrite.rb', line 195

def delete( *range_arguments )
  range, = cast_range( range_arguments )
  op = Delete.new( @stream, range )
  @operations << op
  return op
end

#execute(*range_arguments) ⇒ Object 



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# File 'lib/antlr3/streams/rewrite.rb', line 264

def execute( *range_arguments )
  if range_arguments.empty?
    range = 0 ... @stream.length
  else
    range, = cast_range( range_arguments )
  end
  
  output = ''
  
  tokens = @stream.tokens
  
  operations = reduce
  
  cursor = range.first
  while range.include?( cursor )
    if operation = operations.delete( cursor )
      cursor = operation.execute( output )
    else
      token = tokens[ cursor ]
      output << token.text if token
      cursor += 1
    end
  end
  if operation = operations.delete( cursor ) and
     operation.is_a?( InsertBefore )
    # catch edge 'insert-after' operations
    operation.execute( output )
  end
  
  return output
end

#insert_after(index, text) ⇒ Object 



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# File 'lib/antlr3/streams/rewrite.rb', line 187

def insert_after( index, text )
  index = index.to_i
  index < 0 and index += @stream.length
  op = InsertBefore.new( @stream, index + 1, text )
  @operations << op
  return op
end

#insert_before(index, text) ⇒ Object 



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# File 'lib/antlr3/streams/rewrite.rb', line 179

def insert_before( index, text )
  index = index.to_i
  index < 0 and index += @stream.length
  op = InsertBefore.new( @stream, index, text )
  @operations << op
  return op
end

#reduce ⇒ Object 



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# File 'lib/antlr3/streams/rewrite.rb', line 202

def reduce
  operations = @operations.reverse
  reduced = []
  
  until operations.empty?
    operation = operations.shift
    location = operation.location
    
    case operation
    when Replace
      operations.delete_if do |prior_operation|
        prior_location = prior_operation.location
        
        case prior_operation
        when InsertBefore
          location.include?( prior_location )
        when Replace
          if location.covers?( prior_location )
            true
          elsif location.overlaps?( prior_location )
            conflict!( operation, prior_operation )
          end
        end
      end
    when InsertBefore
      operations.delete_if do |prior_operation|
        prior_location = prior_operation.location
        
        case prior_operation
        when InsertBefore
          if prior_location == location
            operation.text += prior_operation.text
            true
          end
        when Replace
          if location == prior_location.first
            prior_operation.text = operation.text << prior_operation.text.to_s
            operation = nil
            break( false )
          elsif prior_location.include?( location )
            conflict!( operation, prior_operation )
          end
        end
      end
    end
    
    reduced.unshift( operation ) if operation
  end
  
  @operations.replace( reduced )
  
  @operations.inject( {} ) do |map, operation|
    other_operaiton = map[ operation.index ] and
      ANTLR3.bug!( Util.tidy( "      | %s#reduce! should have left only one operation per index,\n      | but %p conflicts with %p\n      END\n    map[ operation.index ] = operation\n    map\n  end\nend\n" ) % [ self.class, operation, other_operaiton ] )

#replace(*range_arguments) ⇒ Object 



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# File 'lib/antlr3/streams/rewrite.rb', line 171

def replace( *range_arguments )
  range, text = cast_range( range_arguments, 1 )
  
  op = Replace.new( @stream, range, text )
  @operations << op
  return op
end

#undo(number_of_operations = 1) ⇒ Object 



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# File 'lib/antlr3/streams/rewrite.rb', line 300

def undo( number_of_operations = 1 )
  @operations.pop( number_of_operations )
end