• Henning Hasemann (14/14) Mar 06 2007 Would it be possible/make sense to have int & co behave as if opCmp and ...
• BCS (4/22) Mar 06 2007 untested but it might work:
• Henning Hasemann (8/13) Mar 06 2007 I tried this last week or so. Result is:
• Frits van Bommel (2/13) Mar 06 2007 IIRC 'is' tests if a _type_ is valid. Try something like is(typeof(i < i...
• Henning Hasemann (9/10) Mar 06 2007 Works quite well, only thing is that
• Frits van Bommel (15/23) Mar 06 2007 No, AFAIK there indeed isn't, but there *is* a way to see if a class has...

Henning Hasemann <hhasemann web.de> writes:

Would it be possible/make sense to have int & co behave as if opCmp and opEquals
where defined for them?

That would make it easier in some situations to request for any type that
is comparable, i.e.

interface Comparable {
	int opCmp(object);
}

would match integer & co.

Alternative would be to have another way to determine if a type is comparable
maybe a a template-thingy (Im not fit enough with templates to say
if one could write such a thing himself without special handling of integral
types)

Henning

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BCS <ao pathlink.com> writes:

Reply to Henning,

 Would it be possible/make sense to have int & co behave as if opCmp
 and opEquals where defined for them?
 
 That would make it easier in some situations to request for any type
 that is comparable, i.e.
 
 interface Comparable {
 int opCmp(object);
 }
 would match integer & co.
 
 Alternative would be to have another way to determine if a type is
 comparable
 maybe a a template-thingy (Im not fit enough with templates to say
 if one could write such a thing himself without special handling of
 integral types)
 Henning
 

untested but it might work:

const T i;
is(i < i);

Henning Hasemann <hhasemann web.de> writes:

 
 untested but it might work:
 
 const T i;
 is(i < i);
 

I tried this last week or so. Result is:
found '<' when expecting ')'

So it seem is() doesnt like "<".

Henning
 
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v4sw7Yhw4ln0pr7Ock2/3ma7uLw5Xm0l6/7DGKi2e6t6ELNSTVXb7AHIMOen5a2Xs5Mr2g5ACPR
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Frits van Bommel <fvbommel REMwOVExCAPSs.nl> writes:

Henning Hasemann wrote:
  
 untested but it might work:

 const T i;
 is(i < i);

 
 I tried this last week or so. Result is:
 found '<' when expecting ')'
 
 So it seem is() doesnt like "<".

IIRC 'is' tests if a _type_ is valid. Try something like is(typeof(i < i)).

Henning Hasemann <hhasemann web.de> writes:

 IIRC 'is' tests if a _type_ is valid. Try something like is(typeof(i < i)).

Works quite well, only thing is that
it yields true for everything that is derived from object,
but these indeed *have* defined opCmp so I guess
there is no real way to find out if the writer of
a class things this class' objects should be comparable
to themselves.

Henning

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v4sw7Yhw4ln0pr7Ock2/3ma7uLw5Xm0l6/7DGKi2e6t6ELNSTVXb7AHIMOen5a2Xs5Mr2g5ACPR
hackerkey.com

Frits van Bommel <fvbommel REMwOVExCAPSs.nl> writes:

Henning Hasemann wrote:
 IIRC 'is' tests if a _type_ is valid. Try something like is(typeof(i < i)).

 
 Works quite well, only thing is that
 it yields true for everything that is derived from object,
 but these indeed *have* defined opCmp so I guess
 there is no real way to find out if the writer of
 a class things this class' objects should be comparable
 to themselves.

No, AFAIK there indeed isn't, but there *is* a way to see if a class has 
an overridden Object.opCmp: (warning: dirty trick)
---
import std.stdio;

class Foo {	// opCmp overridden
	int opCmp(Object o) { return 0; }
}

class Bar { }	// opCmp not overridden

void main()
{
	writefln(&Foo.opCmp != &Object.opCmp);	// prints "true"
	writefln(&Bar.opCmp != &Object.opCmp);	// prints "false"
}
---