digitalmars.D.learn - Copying to an immutable array in a costructor
- bearophile (11/11) Oct 24 2013 This shows a limitation of the D type system:
- Jonathan M Davis (3/14) Oct 24 2013 It's a compiler bug. immutable data should not be initialized more than ...
- bearophile (10/12) Oct 24 2013 My point was another one, regarding this refused code:
- Maxim Fomin (8/20) Oct 24 2013 Reduced:
- Maxim Fomin (10/21) Oct 24 2013 Because control flow check for immutable data is almost absent. I
This shows a limitation of the D type system: import std.algorithm: copy; immutable int[2] data; static this() { foreach (i, x; [10, 20]) data[i] = x; // OK data[] = [10, 20]; // OK [10, 20].copy(data[]); // Error. } void main() {} Bye, bearophile
Oct 24 2013
On Thursday, October 24, 2013 09:02:24 bearophile wrote:This shows a limitation of the D type system: import std.algorithm: copy; immutable int[2] data; static this() { foreach (i, x; [10, 20]) data[i] = x; // OK data[] = [10, 20]; // OK [10, 20].copy(data[]); // Error. } void main() {}It's a compiler bug. immutable data should not be initialized more than once. - Jonathan M Davis
Oct 24 2013
Jonathan M Davis:It's a compiler bug. immutable data should not be initialized more than once.My point was another one, regarding this refused code: import std.algorithm: copy; immutable int[2] data; static this() { [10, 20].copy(data[]); // Error. } void main() {} Bye, bearophile
Oct 24 2013
On Thursday, 24 October 2013 at 10:58:30 UTC, bearophile wrote:Jonathan M Davis:Reduced: immutable int[] data; void foo(int[] data) {} static this() { foo(data); }It's a compiler bug. immutable data should not be initialized more than once.My point was another one, regarding this refused code: import std.algorithm: copy; immutable int[2] data; static this() { [10, 20].copy(data[]); // Error. } void main() {} Bye, bearophile
Oct 24 2013
On Thursday, 24 October 2013 at 07:02:25 UTC, bearophile wrote:This shows a limitation of the D type system: import std.algorithm: copy; immutable int[2] data; static this() { foreach (i, x; [10, 20]) data[i] = x; // OK data[] = [10, 20]; // OK [10, 20].copy(data[]); // Error. } void main() {} Bye, bearophileBecause control flow check for immutable data is almost absent. I don't know any situation where are such checks (except constructors). There is similar issue with respect to initializsing immutable member field in struct constructor. There is issue in bugzilla filed for it (it looks like it will be fixed), where Andrei proposed a concept of cooked object, basically implying control flow for initializaing immutable members. I think that the code you posted as an additional case for the issue.
Oct 24 2013