There are two main problems with lvalue subroutines:

  1. It is impossible to validate the assigned value.

    You cannot inspect the value before the assignment as it isn't accessible.

    You cannot check the value after the assignment but before returning, because the lvalue that receives the assignment must be the last thing in the subroutine before it returns.

  2. The lvalue that receives the assignment must be the last thing in the subroutine.

    Even without considering the first problem above, you often would like to be able to do other things before returning.

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In reply to Re: Is ": lvalue" attribute usefull or something to avoid? by BrowserUk
in thread Is ": lvalue" attribute usefull or something to avoid? by TomDLux

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