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digitalmars.D.learn - Duplicated functions not reported?

reply Jacob Carlborg <doob me.com> writes:
I'm not sure if I'm missing something obvious here, but the following 
code compiles and runs:

void foo() {}
void foo() {}

void main() {}

Although if I do call "foo", the compiler will complain that it matches 
both versions of "foo".

Is this expected behavior of how function overloading works? Is it 
possible to for the compiler to report this error? At least this example 
is pretty obvious for a human to see.

-- 
/Jacob Carlborg
Apr 15
parent reply Stefan Koch <uplink.coder googlemail.com> writes:
On Saturday, 15 April 2017 at 09:17:08 UTC, Jacob Carlborg wrote:
 I'm not sure if I'm missing something obvious here, but the 
 following code compiles and runs:

 void foo() {}
 void foo() {}

 void main() {}

 Although if I do call "foo", the compiler will complain that it 
 matches both versions of "foo".

 Is this expected behavior of how function overloading works? Is 
 it possible to for the compiler to report this error? At least 
 this example is pretty obvious for a human to see.
It would requires an O(n^2) check per declaration. Even it is never used. which would make imports that much more expensive.
Apr 15
next sibling parent Jacob Carlborg <doob me.com> writes:
On 2017-04-15 13:10, Stefan Koch wrote:

 It would requires an O(n^2) check per declaration.
 Even it is never used.
 which would make imports that much more expensive.
Does it need to be that bad? Isn't it possible to do some simple checks with less overhead? Something like first checking the name and the number of parameters (shouldn't require semantic analyze?) and only do the check for those functions that match. I would guess that would be quite few functions that falls within that criteria. Also, only within a single module. -- /Jacob Carlborg
Apr 15
prev sibling parent reply Era Scarecrow <rtcvb32 yahoo.com> writes:
On Saturday, 15 April 2017 at 11:10:01 UTC, Stefan Koch wrote:
 It would requires an O(n^2) check per declaration.
 Even it is never used.
 which would make imports that much more expensive.
Seems wrong to me... If you made a list/array of all the functions (based purely on signatures) then sorted them, then any duplicates would be adjacent. Scanning that list would be O(n-1). This assumes it's done after all functions are scanned and identified, doing it earlier is a waste of time and energy.
Apr 16
parent reply Stefan Koch <uplink.coder googlemail.com> writes:
On Sunday, 16 April 2017 at 10:56:37 UTC, Era Scarecrow wrote:
 On Saturday, 15 April 2017 at 11:10:01 UTC, Stefan Koch wrote:
 It would requires an O(n^2) check per declaration.
 Even it is never used.
 which would make imports that much more expensive.
Seems wrong to me... If you made a list/array of all the functions (based purely on signatures) then sorted them, then any duplicates would be adjacent. Scanning that list would be O(n-1). This assumes it's done after all functions are scanned and identified, doing it earlier is a waste of time and energy.
sorting has O(n^2) worst case complexity. Therefore totaling to O(n^2) worst case again.
Apr 16
next sibling parent reply Temtaime <temtaime gmail.com> writes:
On Sunday, 16 April 2017 at 15:54:16 UTC, Stefan Koch wrote:
 On Sunday, 16 April 2017 at 10:56:37 UTC, Era Scarecrow wrote:
 On Saturday, 15 April 2017 at 11:10:01 UTC, Stefan Koch wrote:
 It would requires an O(n^2) check per declaration.
 Even it is never used.
 which would make imports that much more expensive.
Seems wrong to me... If you made a list/array of all the functions (based purely on signatures) then sorted them, then any duplicates would be adjacent. Scanning that list would be O(n-1). This assumes it's done after all functions are scanned and identified, doing it earlier is a waste of time and energy.
sorting has O(n^2) worst case complexity. Therefore totaling to O(n^2) worst case again.
Why this difficulty ? Function[args][name] funcs; AA lookup is O(1).
Apr 16
parent Stefan Koch <uplink.coder googlemail.com> writes:
On Sunday, 16 April 2017 at 17:10:14 UTC, Temtaime wrote:
 On Sunday, 16 April 2017 at 15:54:16 UTC, Stefan Koch wrote:
 On Sunday, 16 April 2017 at 10:56:37 UTC, Era Scarecrow wrote:
 On Saturday, 15 April 2017 at 11:10:01 UTC, Stefan Koch wrote:
 It would requires an O(n^2) check per declaration.
 Even it is never used.
 which would make imports that much more expensive.
Seems wrong to me... If you made a list/array of all the functions (based purely on signatures) then sorted them, then any duplicates would be adjacent. Scanning that list would be O(n-1). This assumes it's done after all functions are scanned and identified, doing it earlier is a waste of time and energy.
sorting has O(n^2) worst case complexity. Therefore totaling to O(n^2) worst case again.
Why this difficulty ? Function[args][name] funcs; AA lookup is O(1).
AA lookup is _NOT_ O(1). Worst case is O(n).
Apr 16
prev sibling parent Ola Fosheim Grostad <ola.fosheim.grostad gmail.com> writes:
On Sunday, 16 April 2017 at 15:54:16 UTC, Stefan Koch wrote:
 sorting has O(n^2) worst case complexity.
 Therefore totaling to O(n^2) worst case again.
Sorting with comparison is solved in O(n log n). If you have an upper limit on signature length then the problem is solvable for the whole program in O(n). Not that this says an awful lot...
Apr 16