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In article <DCxJ3u.A96@online.tmx.com.au> tony@online.tmx.com.au (Tony
Cook) writes:

|> Is the following legal:

It's legal.

|> class T
|> {
|>   public:
|>     T() {}
|>     // 
|>     T(int, 
|>       T const &def_ = T() // note this - use before end of class
|>     ) { }
|> };

|> int main()
|> {
|>     T t(0);

|>     return 0;
|> }

|> Why it might be legal:
|>     default arguments are evaluated at the point of use.

|> [dcl.fct.default]
|> 9 Default  arguments  are  evaluated  at each point of call before entry
|>   into a function.

Correct.

|> Why it might not be legal:
|>     names for default arguments are bound at point of declaration,
|> and T is not fully defined where the default argument is declared.

|> [dcl.fct.default]
|> 5 Default argument expressions have their names bound  and  their  types
|>   checked at the point of declaration.

|> [class] p2
|>                                                                        A
|>   class is considered defined after the  closing  brace  of  its  class-
|>   specifier  has  been seen even though its member functions are in gen-
|>   eral not yet defined.

Binding a name does not require a complete type.  In fact,
technically, it doesn't require any semantic information concerning
the name.  (In practice, there is no way for you to make a name known
to the compiler without providing some semantic information.)
-- 
James Kanze         Tel.: (+33) 88 14 49 00        email: kanze@gabi-soft.fr
GABI Software, Sarl., 8 rue des Francs-Bourgeois, F-67000 Strasbourg, France
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