Reply to Walter,

> Kirk McDonald wrote:
> 
>> In the spec for the new ForeachRangeStatement, it says:
>> 
>> "If Foreach is foreach, then the variable is set to LwrExpression,
>> then incremented at the end of each iteration."
>> 
>> What does "incremented" mean, exactly? If have a class or struct that
>> defines opAddAssign, would it call foo.opAddAssign(1) (as ++foo
>> does)? Similarly, would the foreach_reverse form call
>> foo.opSubAssign(1)?
>> 
> Right now, it doesn't work with structs/classes, but when it does,
> it'll be as you wrote.
> 

what will this do

foreach(float f; 1 .. toBigFor1ToIncrement)

loop forever?

BCS wrote:
> what will this do
> 
> foreach(float f; 1 .. toBigFor1ToIncrement)
> 
> loop forever?

The same thing as:

	for (float f = 1; f < toBigFor1ToIncrement; f++)

What foreach ranges buy you is:

1) The type of the loop index is automatically inferred
2) The termination condition is evaluated only once

While these may seem trivial, they are often a source of bugs.

Walter Bright wrote:
> Don Clugston wrote:
>> I'm having trouble understanding the difference between "isScalar", "isArithmetic", and "isIntegral". Is this table correct?
>>
>> int uint real wchar
>> Y   Y    Y    N     isArithmetic
>> N   N    Y    N     isFloating
>> Y   Y    N    Y     isIntegral
>> Y   Y    Y    Y     isScalar
>> N   Y    N    N     isUnsigned
>>
>> ----------------
> 
> wchar is arithmetic and unsigned.

OK. Then is there any difference between scalar and arithmetic ?

Don Clugston wrote:
> Walter Bright wrote:
>> Don Clugston wrote:
>>> I'm having trouble understanding the difference between "isScalar", "isArithmetic", and "isIntegral". Is this table correct?
>>>
>>> int uint real wchar
>>> Y   Y    Y    N     isArithmetic
>>> N   N    Y    N     isFloating
>>> Y   Y    N    Y     isIntegral
>>> Y   Y    Y    Y     isScalar
>>> N   Y    N    N     isUnsigned
>>>
>>> ----------------
>>
>> wchar is arithmetic and unsigned.
> 
> OK. Then is there any difference between scalar and arithmetic ?

I haven't checked DMDs handling of this, but if I understand the terms correctly then the difference should be in the handling of complex types (cfloat & friends) which should be arithmetic types but not scalar ones.

"Walter Bright" <newshound1@digitalmars.com> wrote in message news:f82mav$2t9v$4@digitalmars.com...
> Craig Black wrote:
>> Very nice Walter!  Question about traits.  I'm guessing allMembers returns both functions and fields?  Is there an isField or isFunction to differentiate?
>
> You can look at the types to see if they are data or functions. But probably more traits need to be added - I thought I'd wait on that to see just what was required, rather than throw in a lot of useless geegaws. It's hard to predict in advance.

If you had

class A
{
    void function() f;
    void delegate() g;
    void foo() {}
}

What would be f's type, g's type, and foo's type?

Don Clugston wrote:
> Walter Bright wrote:
>> Don Clugston wrote:
>>> I'm having trouble understanding the difference between "isScalar", "isArithmetic", and "isIntegral". Is this table correct?
>>>
>>> int uint real wchar
>>> Y   Y    Y    N     isArithmetic
>>> N   N    Y    N     isFloating
>>> Y   Y    N    Y     isIntegral
>>> Y   Y    Y    Y     isScalar
>>> N   Y    N    N     isUnsigned
>>>
>>> ----------------
>>
>> wchar is arithmetic and unsigned.
> 
> OK. Then is there any difference between scalar and arithmetic ?

scalar includes pointers.

Jarrett Billingsley wrote:
> If you had
> 
> class A
> {
>     void function() f;
>     void delegate() g;
>     void foo() {}
> }
> 
> What would be f's type, g's type, and foo's type? 

f: pointer to function returning void
g: delegate returning void
foo: function returning void

Walter Bright escribió:
> 
> http://www.digitalmars.com/d/1.0/changelog.html
> http://ftp.digitalmars.com/dmd.1.019.zip
> 
> http://www.digitalmars.com/d/changelog.html
> http://ftp.digitalmars.com/dmd.2.003.zip

How can we check specific overloads with __traits? For example,

class A
{
	abstract void foo();
	int foo(int i) { return i; }
}

void main ()
{
	auto isvirtual = __traits(isAbstractFunction, A.foo); // what is it?
}

BTW, the documentation for __traits has isVirtualFunction in the example for isAbstractFunction.

-- 
Carlos Santander Bernal

On Mon, 23 Jul 2007 09:45:57 -0700, Walter Bright wrote:

> Don Clugston wrote:
>> I'm having trouble understanding the difference between "isScalar", "isArithmetic", and "isIntegral". Is this table correct?
>> 
>> int uint real wchar
>> Y   Y    Y    N     isArithmetic
>> N   N    Y    N     isFloating
>> Y   Y    N    Y     isIntegral
>> Y   Y    Y    Y     isScalar
>> N   Y    N    N     isUnsigned
>> 
>> ----------------
> 
> wchar is arithmetic and unsigned.

Are you serious??? Why are we allowed to do mathematics with characters?

    dchar r = power( 'a' * 'b' + 'd' * '€') / '$';

Doesn't make sense so why is wchar arithmetic?

If you insist in this wart, then we also need an 'isCharacter' trait to distinguish characters from numbers.

-- 
Derek Parnell
Melbourne, Australia
skype: derek.j.parnell

On Mon, 23 Jul 2007 12:22:32 -0700, Walter Bright wrote:

> Don Clugston wrote:
>> Walter Bright wrote:
>>> Don Clugston wrote:
>>>> I'm having trouble understanding the difference between "isScalar", "isArithmetic", and "isIntegral". Is this table correct?
>>>>
>>>> int uint real wchar
>>>> Y   Y    Y    N     isArithmetic
>>>> N   N    Y    N     isFloating
>>>> Y   Y    N    Y     isIntegral
>>>> Y   Y    Y    Y     isScalar
>>>> N   Y    N    N     isUnsigned
>>>>
>>>> ----------------
>>>
>>> wchar is arithmetic and unsigned.
>> 
>> OK. Then is there any difference between scalar and arithmetic ?
> 
> scalar includes pointers.

And yet one can do (some) arithmetic on pointers ... !?

import std.stdio;
void main()
{
  int i;
  int* p;
  p = &i;
  p += 2;
  writefln("%s %s", &i, p);
}
-- 
Derek Parnell
Melbourne, Australia
skype: derek.j.parnell