Hi all,

 

I have a question on ocaml, is there a way to write a empty element say a which can make a::ax=ax ? I tried to find out in library, yet I didn't get the right way out, and it doesn't work if I make a=[], so do you know whether there is a technique can realize this function?  I've got stuck on this point for a very long time.
 
thanks

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Su Zhang
PHD Student
Computer Information and Science
Kansas State University