• Simen Kjaeraas (32/32) Mar 21 2008 I'm playing around with templates and mixins of different types, in an ...
• BCS (4/38) Mar 21 2008 I wish they were better (I once has a compile that managed to flush my 2...

"Simen Kjaeraas" <simen.kjaras gmail.com> writes:

I'm playing around with templates and mixins of different types, in an  =

effort to
make a property struct with all manners of overloaded operators (as per
Alternative solutions to returning ref types. in digitalmars.D).

Now, when I use this thing and do something wrong, I get error messages =
 =

with
very user-unfriendly texts. For instance:

/////////////////

int _a;
property!(int, properties.read) a =3D &_a; // properties.read means only=
  =

operators
                                   // that do not change the data are  =

overloaded.
a +=3D 4; // this lines leads to the errors below

/////////////////

test.d(8): Error: 'a' is not a scalar, it is a
   _property!(int,void,"+,-,*,/,%,&,|,^,<<,>>,>>>,~,in","+,-","")
test.d(8): Error: incompatible types for ((a) +=3D (4)):
   '_property!(int,void,"+,-,*,/,%,&,|,^,<<,>>,>>>,~,in","+,-","")' and =
 =

'int'
test.d(8): Error: 'a' is not of arithmetic type, it is a
   _property!(int,void,"+,-,*,/,%,&,|,^,<<,>>,>>>,~,in","+,-","")


As you can see, hardly user-friendly. Now, how can I make them more  =

readable? Do
I need to overload all the other operators with templated functions with=
  =

static
asserts?

-- Simen

BCS <ao pathlink.com> writes:

Reply to Simen,

 I'm playing around with templates and mixins of different types, in an
 effort to
 make a property struct with all manners of overloaded operators (as
 per
 Alternative solutions to returning ref types. in digitalmars.D).
 Now, when I use this thing and do something wrong, I get error
 messages
 with
 very user-unfriendly texts. For instance:
 /////////////////
 
 int _a;
 property!(int, properties.read) a = &_a; // properties.read means only
 operators
 // that do not change the data are
 overloaded.
 a += 4; // this lines leads to the errors below
 
 /////////////////
 
 test.d(8): Error: 'a' is not a scalar, it is a
 _property!(int,void,"+,-,*,/,%,&,|,^,<<,>>,>>>,~,in","+,-","")
 test.d(8): Error: incompatible types for ((a) += (4)):
 '_property!(int,void,"+,-,*,/,%,&,|,^,<<,>>,>>>,~,in","+,-","")'
 and
 'int'
 test.d(8): Error: 'a' is not of arithmetic type, it is a
 _property!(int,void,"+,-,*,/,%,&,|,^,<<,>>,>>>,~,in","+,-","")
 As you can see, hardly user-friendly. Now, how can I make them more
 readable? Do
 I need to overload all the other operators with templated functions
 with
 static
 asserts?

I wish they were better (I once has a compile that managed to flush my 2000+ 
line scroll back buffer x-). But I'm not sure how you could do it without 
loosing information that the user needs to see.