Re: Emulate C's (polymorphic) NULL type
On Monday, 6 June 2016 at 18:33:36 UTC, ParticlePeter wrote: On Monday, 6 June 2016 at 16:19:02 UTC, Alex Parrill wrote: On Monday, 6 June 2016 at 09:43:23 UTC, ParticlePeter wrote: In C NULL can be used as integer as well as null pointer. Is there a way to create such a type in D? The type should have only one value which is obviously (0/null). A extern( C ) function should be able to take it as either one. Overloaded enum pops into my mind as example: enum NULL = 0; enum NULL = null; Is this possible somehow? I already asked about this: https://forum.dlang.org/post/bnkqevhyxwdjjxsct...@forum.dlang.org Tldr; doesn't seem to be possible without multiple alias this or using ABI hacks. O.k., my web search didn't find that topic. The last reply looks promising, wouldn't that work? That's the ABI hack I mentioned. It abuses the fact that on most hardware and compiled, a pointer and a structure containing a single pointer have the same binary representation. It will likely work, but it isn't guarenteed.
Re: Emulate C's (polymorphic) NULL type
On Monday, 6 June 2016 at 18:33:36 UTC, ParticlePeter wrote: On Monday, 6 June 2016 at 16:19:02 UTC, Alex Parrill wrote: On Monday, 6 June 2016 at 09:43:23 UTC, ParticlePeter wrote: In C NULL can be used as integer as well as null pointer. Is there a way to create such a type in D? The type should have only one value which is obviously (0/null). A extern( C ) function should be able to take it as either one. Overloaded enum pops into my mind as example: enum NULL = 0; enum NULL = null; Is this possible somehow? I already asked about this: https://forum.dlang.org/post/bnkqevhyxwdjjxsct...@forum.dlang.org Tldr; doesn't seem to be possible without multiple alias this or using ABI hacks. O.k., my web search didn't find that topic. The last reply looks promising, wouldn't that work? Lets bump it and discuss there.
Re: Emulate C's (polymorphic) NULL type
On Monday, 6 June 2016 at 16:19:02 UTC, Alex Parrill wrote: On Monday, 6 June 2016 at 09:43:23 UTC, ParticlePeter wrote: In C NULL can be used as integer as well as null pointer. Is there a way to create such a type in D? The type should have only one value which is obviously (0/null). A extern( C ) function should be able to take it as either one. Overloaded enum pops into my mind as example: enum NULL = 0; enum NULL = null; Is this possible somehow? I already asked about this: https://forum.dlang.org/post/bnkqevhyxwdjjxsct...@forum.dlang.org Tldr; doesn't seem to be possible without multiple alias this or using ABI hacks. O.k., my web search didn't find that topic. The last reply looks promising, wouldn't that work?
Re: Emulate C's (polymorphic) NULL type
On Monday, 6 June 2016 at 09:43:23 UTC, ParticlePeter wrote: In C NULL can be used as integer as well as null pointer. Is there a way to create such a type in D? The type should have only one value which is obviously (0/null). A extern( C ) function should be able to take it as either one. Overloaded enum pops into my mind as example: enum NULL = 0; enum NULL = null; Is this possible somehow? I already asked about this: https://forum.dlang.org/post/bnkqevhyxwdjjxsct...@forum.dlang.org Tldr; doesn't seem to be possible without multiple alias this or using ABI hacks.
Re: Emulate C's (polymorphic) NULL type
On Monday, 6 June 2016 at 12:09:33 UTC, ParticlePeter wrote: I don't see the connection here, you introduced two symbols with two different types. I want one symbol which can pose as two different (constant) types. Ah, my apologies, I misunderstood the question.
Re: Emulate C's (polymorphic) NULL type
On Monday, 6 June 2016 at 11:40:11 UTC, Anonymouse wrote: On Monday, 6 June 2016 at 09:43:23 UTC, ParticlePeter wrote: In C NULL can be used as integer as well as null pointer. Is there a way to create such a type in D? The type should have only one value which is obviously (0/null). A extern( C ) function should be able to take it as either one. Overloaded enum pops into my mind as example: enum NULL = 0; enum NULL = null; Is this possible somehow? If you want it for use in logical expressions then implicit boolean conversion will treat them as the same. https://dpaste.dzfl.pl/d82f60657c37 I don't see the connection here, you introduced two symbols with two different types. I want one symbol which can pose as two different (constant) types.
Re: Emulate C's (polymorphic) NULL type
On Monday, 6 June 2016 at 09:43:23 UTC, ParticlePeter wrote: In C NULL can be used as integer as well as null pointer. Is there a way to create such a type in D? The type should have only one value which is obviously (0/null). A extern( C ) function should be able to take it as either one. Overloaded enum pops into my mind as example: enum NULL = 0; enum NULL = null; Is this possible somehow? If you want it for use in logical expressions then implicit boolean conversion will treat them as the same. https://dpaste.dzfl.pl/d82f60657c37
Re: Emulate C's (polymorphic) NULL type
On Monday, 6 June 2016 at 09:43:23 UTC, ParticlePeter wrote: A extern( C ) function should be able to take it as either one. Missed this bit. Not sure about that one.
Emulate C's (polymorphic) NULL type
In C NULL can be used as integer as well as null pointer. Is there a way to create such a type in D? The type should have only one value which is obviously (0/null). A extern( C ) function should be able to take it as either one. Overloaded enum pops into my mind as example: enum NULL = 0; enum NULL = null; Is this possible somehow?
