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digitalmars.D - Inference of Scoped Destruction

reply =?UTF-8?B?Tm9yZGzDtnc=?= <per.nordlow gmail.com> writes:
Are there any plans to D compilers to use recent DIP-1000 to 
infer scoped destruction of GC-allocated data such as in the 
following case:

T sum(T)(in T[] x) // x cannot escape scope of `sum`
{
     /// calculate and return sum of `x` ...
}

double f(size_t n)
{
     auto x = new int[n]; // scoped (deallocation) should be 
inferred
     auto y = sum(x); // cannot alias `x`
     return y;
}

I believe this would make D more competitive against Rust's and 
C++'s (more) deterministic RAII memory management.

How would this interact with explicit scope-qualification of `x`?
Nov 30
next sibling parent reply Stefan Koch <uplink.coder googlemail.com> writes:
On Thursday, 30 November 2017 at 16:31:25 UTC, Nordlöw wrote:
 Are there any plans to D compilers to use recent DIP-1000 to 
 infer scoped destruction of GC-allocated data such as in the 
 following case:

 T sum(T)(in T[] x) // x cannot escape scope of `sum`
 {
     /// calculate and return sum of `x` ...
 }

 double f(size_t n)
 {
     auto x = new int[n]; // scoped (deallocation) should be 
 inferred
     auto y = sum(x); // cannot alias `x`
     return y;
 }

 I believe this would make D more competitive against Rust's and 
 C++'s (more) deterministic RAII memory management.

 How would this interact with explicit scope-qualification of 
 `x`?
The problem with this; as with most types of inference is the time it can take. And the number of false negatives.
Nov 30
parent =?UTF-8?B?Tm9yZGzDtnc=?= <per.nordlow gmail.com> writes:
On Thursday, 30 November 2017 at 16:50:02 UTC, Stefan Koch wrote:
 On Thursday, 30 November 2017 at 16:31:25 UTC, Nordlöw wrote:
 Are there any plans to D compilers to use recent DIP-1000 to 
 infer scoped destruction of GC-allocated data such as in the 
 following case:

 T sum(T)(in T[] x) // x cannot escape scope of `sum`
 {
     /// calculate and return sum of `x` ...
 }

 double f(size_t n)
 {
     auto x = new int[n]; // scoped (deallocation) should be 
 inferred
     auto y = sum(x); // cannot alias `x`
     return y;
 }

 I believe this would make D more competitive against Rust's 
 and C++'s (more) deterministic RAII memory management.

 How would this interact with explicit scope-qualification of 
 `x`?
The problem with this; as with most types of inference is the time it can take. And the number of false negatives.
Is there a formal definition of the complexity of such an inference?
Nov 30
prev sibling parent reply Nick Treleaven <nick geany.org> writes:
On Thursday, 30 November 2017 at 16:31:25 UTC, Nordlöw wrote:
 How would this interact with explicit scope-qualification of 
 `x`?
That would allow the compiler to avoid GC allocation for x. It seems essentially the same case as Walter describes here: http://forum.dlang.org/post/ofo9f5$2bt7$1 digitalmars.com
Dec 04
parent =?UTF-8?B?Tm9yZGzDtnc=?= <per.nordlow gmail.com> writes:
On Monday, 4 December 2017 at 16:03:50 UTC, Nick Treleaven wrote:
 On Thursday, 30 November 2017 at 16:31:25 UTC, Nordlöw wrote:
 How would this interact with explicit scope-qualification of 
 `x`?
That would allow the compiler to avoid GC allocation for x. It seems essentially the same case as Walter describes here: http://forum.dlang.org/post/ofo9f5$2bt7$1 digitalmars.com
Nice. Thanks.
Dec 04