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digitalmars.D.learn - overload of array operations

reply Jay Norwood <jayn prismnet.com> writes:
Is it possible to overload array operations
Oct 14 2011
parent reply Jonathan M Davis <jmdavisProg gmx.com> writes:
On Friday, October 14, 2011 11:30:25 Jay Norwood wrote:

 Is it possible to overload array operations


Please be more specific. Are you asking whether a struct or class can overload 
the indexing and slicing operators? If so, the answer is yes.

http://d-programming-language.org/operatoroverloading.html

- Jonathan M Davis
Oct 14 2011
next sibling parent Jay Norwood <jayn prismnet.com> writes:
Jonathan M Davis Wrote:


 On Friday, October 14, 2011 11:30:25 Jay Norwood wrote:

 Is it possible to overload array operations


 
 Please be more specific. Are you asking whether a struct or class can overload 
 the indexing and slicing operators? If so, the answer is yes.
 
 http://d-programming-language.org/operatoroverloading.html
 
 - Jonathan M Davis



I'm interested, for example,  in overloading the  + operation for arrays that
is documented to generate a vector add operation.  I assume there would need to
be a name for that operation in order to overload it.
Thanks,
Jay
Oct 14 2011
prev sibling parent reply Jay Norwood <jayn prismnet.com> writes:
Jonathan M Davis Wrote:


 On Friday, October 14, 2011 11:30:25 Jay Norwood wrote:

 Is it possible to overload array operations


 
 Please be more specific. Are you asking whether a struct or class can overload 
 the indexing and slicing operators? If so, the answer is yes.
 
 http://d-programming-language.org/operatoroverloading.html
 
 - Jonathan M Davis



to be more specific, I'm interested in overloading the vector operations on
arrays described at this link, search for "vector operation"

http://www.digitalmars.com/d/2.0/arrays.html
Oct 14 2011
parent reply Jonathan M Davis <jmdavisProg gmx.com> writes:
On Friday, October 14, 2011 15:29:17 Jay Norwood wrote:

 Jonathan M Davis Wrote:

 On Friday, October 14, 2011 11:30:25 Jay Norwood wrote:

 Is it possible to overload array operations


 
 Please be more specific. Are you asking whether a struct or class can
 overload the indexing and slicing operators? If so, the answer is yes.
 
 http://d-programming-language.org/operatoroverloading.html
 
 - Jonathan M Davis


 
 to be more specific, I'm interested in overloading the vector operations on
 arrays described at this link, search for "vector operation"
 
 http://www.digitalmars.com/d/2.0/arrays.html


You could probably do it if you're fancy, but there's no explicit way to have 
a struct or class operate like that. If you really wanted to though, you could 
overload opSlice on your struct to return a specific type which then overloaded 
opBinary for + and then have that return a new struct with the changed values. 
But that borders on overloaded operator abuse.

Vector operations are really only intended for arrays.

- Jonathan M Davis
Oct 14 2011
next sibling parent reply Jay Norwood <jayn prismnet.com> writes:
Jonathan M Davis Wrote:


 On Friday, October 14, 2011 15:29:17 Jay Norwood wrote:

 Jonathan M Davis Wrote:

 On Friday, October 14, 2011 11:30:25 Jay Norwood wrote:

 Is it possible to overload array operations


 
 Please be more specific. Are you asking whether a struct or class can
 overload the indexing and slicing operators? If so, the answer is yes.
 
 http://d-programming-language.org/operatoroverloading.html
 
 - Jonathan M Davis


 
 to be more specific, I'm interested in overloading the vector operations on
 arrays described at this link, search for "vector operation"
 
 http://www.digitalmars.com/d/2.0/arrays.html


 
 You could probably do it if you're fancy, but there's no explicit way to have 
 a struct or class operate like that. If you really wanted to though, you could 
 overload opSlice on your struct to return a specific type which then
overloaded 
 opBinary for + and then have that return a new struct with the changed values. 
 But that borders on overloaded operator abuse.
 
 Vector operations are really only intended for arrays.
 
 - Jonathan M Davis



Yes, I intended to try to overload the array operations on an array of
structures.  I just want to use the simple syntax for the operations.

a[]= b[]+c[];
a[] = b[] + 4;
a[] *= 4;

where a, b, c are arrays of structures, and then overload the operations.   It
seems to me that should require names for the array operations being overloaded.
Oct 14 2011
next sibling parent "Jonathan M Davis" <jmdavisProg gmx.com> writes:
On Friday, October 14, 2011 16:12 Jay Norwood wrote:

 Jonathan M Davis Wrote:

 On Friday, October 14, 2011 15:29:17 Jay Norwood wrote:

 Jonathan M Davis Wrote:

 On Friday, October 14, 2011 11:30:25 Jay Norwood wrote:

 Is it possible to overload array operations


 
 Please be more specific. Are you asking whether a struct or class can
 overload the indexing and slicing operators? If so, the answer is
 yes.
 
 http://d-programming-language.org/operatoroverloading.html
 
 - Jonathan M Davis


 
 to be more specific, I'm interested in overloading the vector
 operations on arrays described at this link, search for "vector
 operation"
 
 http://www.digitalmars.com/d/2.0/arrays.html


 
 You could probably do it if you're fancy, but there's no explicit way to
 have a struct or class operate like that. If you really wanted to
 though, you could overload opSlice on your struct to return a specific
 type which then overloaded opBinary for + and then have that return a
 new struct with the changed values. But that borders on overloaded
 operator abuse.
 
 Vector operations are really only intended for arrays.
 
 - Jonathan M Davis


 
 Yes, I intended to try to overload the array operations on an array of
 structures. I just want to use the simple syntax for the operations.
 
 a[]= b[]+c[];
 a[] = b[] + 4;
 a[] *= 4;
 
 where a, b, c are arrays of structures, and then overload the operations. 
 It seems to me that should require names for the array operations being
 overloaded.


So, you want to have use vector operations on arrays of structs rather than 
use vector operations on a struct or class? If that's what you want, then 
overload the arithmetic operations on the struct as normal, and then use 
vector operations on the array holding the structs. It may work. I don't know. 
If it doesn't, then you're out of luck and can't use the built in syntax. And 
if does, well then there you go.

- Jonathan M Davis
Oct 14 2011
prev sibling parent reply Timon Gehr <timon.gehr gmx.ch> writes:
On 10/15/2011 01:12 AM, Jay Norwood wrote:

 Jonathan M Davis Wrote:


 On Friday, October 14, 2011 15:29:17 Jay Norwood wrote:

 Jonathan M Davis Wrote:

 On Friday, October 14, 2011 11:30:25 Jay Norwood wrote:

 Is it possible to overload array operations


 Please be more specific. Are you asking whether a struct or class can
 overload the indexing and slicing operators? If so, the answer is yes.

 http://d-programming-language.org/operatoroverloading.html

 - Jonathan M Davis


 to be more specific, I'm interested in overloading the vector operations on
 arrays described at this link, search for "vector operation"

 http://www.digitalmars.com/d/2.0/arrays.html


 You could probably do it if you're fancy, but there's no explicit way to have
 a struct or class operate like that. If you really wanted to though, you could
 overload opSlice on your struct to return a specific type which then overloaded
 opBinary for + and then have that return a new struct with the changed values.
 But that borders on overloaded operator abuse.

 Vector operations are really only intended for arrays.

 - Jonathan M Davis



 Yes, I intended to try to overload the array operations on an array of
structures.  I just want to use the simple syntax for the operations.

 a[]= b[]+c[];
 a[] = b[] + 4;
 a[] *= 4;

 where a, b, c are arrays of structures, and then overload the operations.   It
seems to me that should require names for the array operations being overloaded.


I agree. It is odd that we have opSliceUnary but not opSliceBinary.
Oct 17 2011
parent bearophile <bearophileHUGS lycos.com> writes:
Timon Gehr:


 I agree. It is odd that we have opSliceUnary but not opSliceBinary.


If you think something useful is missing, then file a Bugzilla enhancement
request.

Bye,
bearophile
Oct 17 2011
prev sibling parent Timon Gehr <timon.gehr gmx.ch> writes:
On 10/14/2011 09:43 PM, Jonathan M Davis wrote:

 On Friday, October 14, 2011 15:29:17 Jay Norwood wrote:

 Jonathan M Davis Wrote:

 On Friday, October 14, 2011 11:30:25 Jay Norwood wrote:

 Is it possible to overload array operations


 Please be more specific. Are you asking whether a struct or class can
 overload the indexing and slicing operators? If so, the answer is yes.

 http://d-programming-language.org/operatoroverloading.html

 - Jonathan M Davis


 to be more specific, I'm interested in overloading the vector operations on
 arrays described at this link, search for "vector operation"

 http://www.digitalmars.com/d/2.0/arrays.html


 You could probably do it if you're fancy, but there's no explicit way to have
 a struct or class operate like that. If you really wanted to though, you could
 overload opSlice on your struct to return a specific type which then overloaded
 opBinary for + and then have that return a new struct with the changed values.
 But that borders on overloaded operator abuse.

 Vector operations are really only intended for arrays.

 - Jonathan M Davis


I disagree. Operator overloads are there to make types act like built-in 
types, which is what he wants. Overloaded operator abuse is the act of 
creating a type that uses the operators for different semantics than the 
built-in ones.

What you describe is actually close to how the language handles dynamic 
array slices. But reproducing the behavior with operator overloading 
does indeed not work nicely because of type inference. (we'd need a way 
to overload the typeof operator ;))
Oct 17 2011