[Issue 8408] Purity calculation should be improved
http://d.puremagic.com/issues/show_bug.cgi?id=8408 --- Comment #15 from github-bugzi...@puremagic.com 2013-03-24 20:57:04 PDT --- Commits pushed to master at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/b6a809346a43c7fbf350bd4181d350dd9b2cd4e6 Merge pull request #1110 from 9rnsr/fix8408 https://github.com/D-Programming-Language/dmd/commit/ee06e4a38cb7e35fe046ffd4c5a938063c48dc30 Merge pull request #1519 from 9rnsr/fix_purity -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 8408] Purity calculation should be improved
http://d.puremagic.com/issues/show_bug.cgi?id=8408 --- Comment #14 from github-bugzi...@puremagic.com 2013-03-03 16:07:38 PST --- Commit pushed to master at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/ee06e4a38cb7e35fe046ffd4c5a938063c48dc30 Merge pull request #1519 from 9rnsr/fix_purity Refactoring/improvement of issue 8408, and additionally fixing Issue 8998 -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 8408] Purity calculation should be improved
http://d.puremagic.com/issues/show_bug.cgi?id=8408 --- Comment #12 from yebblies yebbl...@gmail.com 2013-01-17 01:07:31 EST --- *** Issue 6783 has been marked as a duplicate of this issue. *** -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 8408] Purity calculation should be improved
http://d.puremagic.com/issues/show_bug.cgi?id=8408 yebblies yebbl...@gmail.com changed: What|Removed |Added CC||yebbl...@gmail.com --- Comment #13 from yebblies yebbl...@gmail.com 2013-01-17 01:14:02 EST --- Is issue 8998 a regression caused by this patch? -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 8408] Purity calculation should be improved
http://d.puremagic.com/issues/show_bug.cgi?id=8408 Walter Bright bugzi...@digitalmars.com changed: What|Removed |Added Status|NEW |RESOLVED CC||bugzi...@digitalmars.com Resolution||FIXED -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 8408] Purity calculation should be improved
http://d.puremagic.com/issues/show_bug.cgi?id=8408 --- Comment #9 from bearophile_h...@eml.cc 2012-12-10 18:31:16 PST --- (In reply to comment #8) I'm not sure that this should be allowed. foo1 can rewrite the elements referred from arr, then it is deduced to weak purity. In current principle, the returned value from weak purity function cannot be converted to immutable implicitly (it is only allowed for strong purity function). If you change the signature of foo1 to: char[] foo1(const int[] arr) pure; Then foo1 will be deduced to strong purity, and implicit conversion to immutable for initializing x1 will be succeeded. You are right, thank you for your answer. (If you want me/us to try to suggest improvements in how you write in English, I am willing to help you, despite I am not a good English teacher.) -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 8408] Purity calculation should be improved
http://d.puremagic.com/issues/show_bug.cgi?id=8408
timon.g...@gmx.ch changed:
What|Removed |Added
CC||timon.g...@gmx.ch
--- Comment #10 from timon.g...@gmx.ch 2012-12-10 18:37:41 PST ---
(In reply to comment #8)
(In reply to comment #6)
Is it correct that x1 refused and x2 accepted?
char[] foo1(int[] arr) pure {
return new char[10];
}
immutable(char)[] foo2(int[] arr) pure {
return new char[10];
}
void main(string[] args) {
immutable x1 = foo1([1, 2]); // Error: cannot implicitly convert
immutable x2 = foo2([1, 2]); // OK
}
I'm not sure that this should be allowed.
...
Why not? It is known at the call site that anything foo1 will return is newly
allocated. Strong or weak purity is irrelevant.
--
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
--- You are receiving this mail because: ---
[Issue 8408] Purity calculation should be improved
http://d.puremagic.com/issues/show_bug.cgi?id=8408
--- Comment #11 from Kenji Hara k.hara...@gmail.com 2012-12-10 19:39:00 PST
---
(In reply to comment #10)
(In reply to comment #8)
(In reply to comment #6)
I'm not sure that this should be allowed.
...
Why not? It is known at the call site that anything foo1 will return is newly
allocated. Strong or weak purity is irrelevant.
Your argument had be true.
I had re-read issue 5081, and could be believed that between the purity level
(strong, constant, weak) and the conversion possibility to immutable of
returned value are irrelevant.
From: http://d.puremagic.com/issues/show_bug.cgi?id=5081#c2
Note actually that as long as you can verify the return value did not come
directly from the parameters, it's also possible to implicitly cast to
immutable.
For example:
pure T[] mydup(T)(const(T)[] param) {...}
It's provable that the return value did not come from param (without a cast),
because you can't implicitly cast param to T[]. So you can cast the result to
immutable, even if param began as mutable.
The last sentence describes the ideal behavior.
Thanks a lot!
--
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
--- You are receiving this mail because: ---
[Issue 8408] Purity calculation should be improved
http://d.puremagic.com/issues/show_bug.cgi?id=8408 --- Comment #7 from bearophile_h...@eml.cc 2012-12-06 18:07:32 PST --- (In reply to comment #6) Is it correct that x1 refused and x2 accepted? I guess I have to wait or Issue 8409 to be fixed before looking for possible troubles. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 8408] Purity calculation should be improved
http://d.puremagic.com/issues/show_bug.cgi?id=8408
--- Comment #8 from Kenji Hara k.hara...@gmail.com 2012-12-06 19:33:50 PST ---
(In reply to comment #6)
Is it correct that x1 refused and x2 accepted?
char[] foo1(int[] arr) pure {
return new char[10];
}
immutable(char)[] foo2(int[] arr) pure {
return new char[10];
}
void main(string[] args) {
immutable x1 = foo1([1, 2]); // Error: cannot implicitly convert
immutable x2 = foo2([1, 2]); // OK
}
I'm not sure that this should be allowed.
foo1 can rewrite the elements referred from arr, then it is deduced to weak
purity. In current principle, the returned value from weak purity function
cannot be converted to immutable implicitly (it is only allowed for strong
purity function).
If you change the signature of foo1 to:
char[] foo1(const int[] arr) pure;
Then foo1 will be deduced to strong purity, and implicit conversion to
immutable for initializing x1 will be succeeded.
--
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
--- You are receiving this mail because: ---
[Issue 8408] Purity calculation should be improved
http://d.puremagic.com/issues/show_bug.cgi?id=8408
--- Comment #6 from bearophile_h...@eml.cc 2012-12-05 17:36:09 PST ---
Is it correct that x1 refused and x2 accepted?
char[] foo1(int[] arr) pure {
return new char[10];
}
immutable(char)[] foo2(int[] arr) pure {
return new char[10];
}
void main(string[] args) {
immutable x1 = foo1([1, 2]); // Error: cannot implicitly convert
immutable x2 = foo2([1, 2]); // OK
}
--
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
--- You are receiving this mail because: ---
[Issue 8408] Purity calculation should be improved
http://d.puremagic.com/issues/show_bug.cgi?id=8408 --- Comment #5 from github-bugzi...@puremagic.com 2012-12-03 22:00:20 PST --- Commits pushed to master at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/41c52a324d0526a079039041c64afc1d3983eb58 fix Issue 8408 - Purity calculation should be improved https://github.com/D-Programming-Language/dmd/commit/b6a809346a43c7fbf350bd4181d350dd9b2cd4e6 Merge pull request #1110 from 9rnsr/fix8408 Issue 8408 - Purity calculation should be improved -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 8408] Purity calculation should be improved
http://d.puremagic.com/issues/show_bug.cgi?id=8408 --- Comment #4 from bearophile_h...@eml.cc 2012-11-12 20:23:55 PST --- *** Issue 9011 has been marked as a duplicate of this issue. *** -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 8408] Purity calculation should be improved
http://d.puremagic.com/issues/show_bug.cgi?id=8408 Kenji Hara k.hara...@gmail.com changed: What|Removed |Added Keywords||pull --- Comment #1 from Kenji Hara k.hara...@gmail.com 2012-09-09 06:21:21 PDT --- https://github.com/D-Programming-Language/dmd/pull/1110 -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 8408] Purity calculation should be improved
http://d.puremagic.com/issues/show_bug.cgi?id=8408 bearophile_h...@eml.cc changed: What|Removed |Added CC||bearophile_h...@eml.cc --- Comment #2 from bearophile_h...@eml.cc 2012-09-09 07:03:15 PDT --- This rule makes more functions (tagged as pure) become strongly pure, this is positive. On the other hand for the programmer it's increasingly harder to know if a function is weak pure or strongly pure just looking at it. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 8408] Purity calculation should be improved
http://d.puremagic.com/issues/show_bug.cgi?id=8408 --- Comment #3 from Kenji Hara k.hara...@gmail.com 2012-09-09 07:24:46 PDT --- (In reply to comment #2) This rule makes more functions (tagged as pure) become strongly pure, this is positive. Thanks. But, I've been filed this as a part of issue 8409, so the pull request doesn't cover all cases. On the other hand for the programmer it's increasingly harder to know if a function is weak pure or strongly pure just looking at it. I think it is not so difficult if you summarize it. - If the function can modify function argument through its parameters, it is weakly pure. - If the function arguments don't appear in the part of the returned value, or the returned value is not a part of arguments, then it is strongly pure. - Otherwise, it is constant pure. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
