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  1. Commons JEXL
  2. JEXL-168

Dedicated operator for String concatenation

    Details

    • Type: Improvement
    • Status: Closed
    • Priority: Minor
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 3.0
    • Labels:
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      Description

      While overloaded '+' operator basically works with Strings in many cases, it works with them in unpredictable manner, for example, if we try to concatenate two parts of IP address with expression "127.0" + "0.1" it will give us the result 127.1 by successfully trying first to convert both operands to numbers and perform addtion. In generic algorithm that combines two parts of some code from database it is hard to say what characters those codes might be consist of, and when this algorithm will eventually break. I understand that this syntax has neverthelless a long history, and changing its behaviour may break many legacy applications. And via the extension of JexlArithmetic we can override add method to support different priority for Strings, but that just means that default implementation of the very basic operation is not ideal. In my case I consider refraining from usage of '+' for Strings altogether and overriding some other operator like '|', with less side effects, but anyway constructs like 127 | 1 will divert to original implementation. So I suggest that we could have a dedicated operator for concatenation, like for example in "EL 3.0" they reserved "+=" for this purpose, and regardless of types of operands it will convert to strings both parts and return concatenation.

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            • Assignee:
              henrib Henri Biestro
              Reporter:
              dmitri_blinov Dmitri Blinov
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