couple of really noob questions (ranges, toString)

[Ali Çehreli]

Jonathan M Davis wrote:

 > In some languages (certainly C++, though I'm
 > not sure about D), returning a value which isn't used can mean a 
wasted copy or
 > object construction which can be inefficient (particularly when 
dealing with large
 > objects on the stack). Whether a pop function returns anything tends 
to depend
 > on how much an efficiency concern the library writer thinks that it 
is and how
 > likely they think that it is that the popped value is going to be wanted.

The stronger reason why pop() doesn't return the object in C++ is about 
exception safety.

To me this topic is one of the most fascinating stories in C++'s 
history. Very briefly, Tom Cargill noted that exception safety gave a 
false sense of security and invited the C++ community to write an 
"exception-correct version of Stack":

 
http://ptgmedia.pearsoncmg.com/images/020163371x/supplements/Exception_Handling_Article.html

It took the community years to come up with an understanding of C++ 
exception safety. Herb Sutter posted the following "guru of the week" 
puzzle:

   http://www.gotw.ca/gotw/008.htm

which eventually ended up being in his later book "Exceptional C++", 
which turned out to be the biggest eye opener for me. Especially the 
exception safety section must be understood by any C++ programmer.

The solution for Tom Cargill's challenge turned out to be "cohesion", 
where pop() should not return the value; that should be provided by 
top(). The efficiency that came from having top() was a bonus.

Ali