Name and lifetime of variables at compile time

Question

From all the languages that I know (Java, C++), the name and the lifetime of a variable is always known at compile time. Is there any language for which the name and lifetime will be bound at run time?

Furthermore, I'm playing with C++ smart pointers at the moment. When is the life time known as well as the scope?

The question is very vague.... What is "variable"? Objects can have dynamic properties, even in C++ if you inherit from base object which supports them, and then these may be indistinguishable from properties defined at compile time, when accessing the instnce from a more dynamic language like Javascript or Python. Example: http://doc.qt.io/qt-5/qobject.html#setProperty — hyde, Dec 05 '15 at 22:51
I fail to understand, what is the use of a variable that you don't know the name of? Could you give an example? — Ashkan, Dec 05 '15 at 22:55

score 0 · Answer 1 · answered Dec 05 '15 at 22:33

With C++ smart pointers, the scope of the smart pointer is the regular scope. The scope of the managed object is determined by the smart pointers behavior.

There are a lot of languages that employ dynamic/runtime scoping. Javascript, PERL, PHP is a few. https://en.wikipedia.org/wiki/Scope_%28computer_science%29#Dynamic_scoping

score 0 · Answer 2 · edited May 23 '17 at 12:30

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with java, NO a priori , or very difficult

see this: Is it possible to create variables at runtime in Java?

What can you do with that at runtime ?

You can reference variables, as you want (in an array, integer, in a Map ...)

edited May 23 '17 at 12:30

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answered Dec 05 '15 at 22:36

guillaume girod-vitouchkina

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Name and lifetime of variables at compile time

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