On 4/1/13 at 5:40 AM, sa...@ccs.neu.edu (Sam Tobin-Hochstadt) wrote:
Using `.dispose()` is manual management of the allocation and
deallocation of object. Manual memory management is fundamentally
non-modular -- you can't encapsulate it in a library, and it requires
describing memory management behavior in all your function
specifications, the way that C libraries do. It's certainly possible
to write large, complex apps in C. But that's not evidence that we
should bring those practices to JS.
There are a bunch of different reasons for wanting to "dispose"
an object in memory. With the malloc/free system from C, you
usually dispose objects to recover their backing memory for
future use. The C version is not memory safe.
If you are paying for the memory, you may be willing to break
things to be able to stop paying. There may be some other
reasons for causing an object to stop working and as a side
effect recover most of its memory. A proxy can provide this
service for JS, along with a number of other techniques all of
which will be memory safe.
For short-lived programs, you can ignore memory disposal if the
system running them will free the memory when they exit. This
technique is memory safe and even works with mismanagement of
references in a garbage collected systems. Having a system which
supports just exiting and recovering memory is valuable for
ad-hoc programming environments. It might also be valuable for
ads running in long-lived web pages. Possibly some of the safe
JS execution environments provide this service for the programs
they mediate.
Memory safety is one really good reason to choose JS over C.
Cheers - Bill
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