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digitalmars.D.learn - offsetof + foreach

reply Ellery Newcomer <ellery-newcomer utulsa.edu> writes:
I have a struct buffer, and I want to print out its members' offsetof.

This:

foreach(i,_t; buffer.tupleof) {
             writefln("%s : %s", _t.stringof, _t.offsetof);
         }

complains

Error: undefined identifier 'offsetof'

what should I be doing?
Sep 07 2012
parent reply Ellery Newcomer <ellery-newcomer utulsa.edu> writes:
On 09/07/2012 10:31 AM, Ellery Newcomer wrote:

 I have a struct buffer, and I want to print out its members' offsetof.

 This:

 foreach(i,_t; buffer.tupleof) {
              writefln("%s : %s", _t.stringof, _t.offsetof);
          }

 complains

 Error: undefined identifier 'offsetof'

 what should I be doing?


nevermind, I remember tupleof + foreach has always been broken

writefln("%s : %s", buffer.tupleof[i].stringof, buffer.tupleof[i].offsetof);
Sep 07 2012
parent "Kenji Hara" <k.hara.pg gmail.com> writes:
On Friday, 7 September 2012 at 17:32:43 UTC, Ellery Newcomer 
wrote:

 On 09/07/2012 10:31 AM, Ellery Newcomer wrote:

 I have a struct buffer, and I want to print out its members' 
 offsetof.

 This:

 foreach(i,_t; buffer.tupleof) {
             writefln("%s : %s", _t.stringof, _t.offsetof);
         }

 complains

 Error: undefined identifier 'offsetof'

 what should I be doing?


 nevermind, I remember tupleof + foreach has always been broken

 writefln("%s : %s", buffer.tupleof[i].stringof, 
 buffer.tupleof[i].offsetof);


I think this is expected behavior.
In foreach body, _t is a copy of field value, and it's not 
buffer's field itself.

Your code is equivalent with:

     foreach(i,_; buffer.tupleof) {
         auto _t = buffer.tupleof[i];	// _t is a normal variable
         writefln("%s : %s", _t.stringof, _t.offsetof);
     }

Then you cannot get offsetof property from _t;

Regards.

Kenji Hara
Sep 08 2012