$literal = "Hello"; $vv = "literal"; echo $$vv; // => prints "Hello"
Are there actually any real use-cases for this language feature?
Assuming a url of
That's a pretty standard practical use of variable variables. Neat trick, but you should be extremely careful when using it, over/abusing it will certainly lead to horribly unmaintainable code.
Disclaimer: The code presented in the answer is only intended to illustrate the use of the feature. It does not cover proper design, security, maintainability, or sanity. Do not use.
Honestly? In nearly 10 years of PHP experience I've never encountered a problem to which the only solution (or indeed the best solution from a choice) was to use a variable variable. The closest I've got is being able to access constants on an instance of a class such as
I suspect it's one of the many warts that exist in PHP that seemed like a good idea at the time.
So in answer to your question, if there are use cases where it's the best or only approach to a particular problem, I've not seen them.