Other Complications

• Commutative and reversible Operators (Add, ==, �<�, �) Handle by:

  • adjusting hash function to ignore/canonicalize order of childen
  • enhance compare routine to treat these nodes specially

• Detecting (Statement) Sequence Clones

  • Statements, argument lists, other language lists per syntax
  • Clone check limited to trees only finds stmt seqs at block end
  • Solution: Special logic to find cloned statement sequences
    • AST nodes that represent sequences must be identified specially
    • Build up lists of pairs of sequence nodes having clone children

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