stdio line-streaming revisited

[Sean Kelly]

Andrei Alexandrescu (See Website For Email) wrote:
> kris wrote:
>> Sean Kelly wrote:
>> [snip]
>>> I must be missing something.  Why is the following not acceptable?
>>>
>>>     import tango.io.Console;
>>>
>>>     void main()
>>>     {
>>>         char[] name;
>>>         Cout( "Please enter your name: " ).flush;
>>>         Cin.nextLine( name );
>>>         Cout( "Hello, " )( name )( "!" );
>>>     }
>>
>>
>> There used to be a tango/example like this variation:
>>
>>     import tango.io.Console;
>>
>>     void main()
>>     {
>>         Cout ("Please enter your name: ").flush;
>>         Cout ("Hello, ") (Cin.get);
>>     }
> 
> Ah, also, the last line is translated into:
> 
> Cout.opCall("Hello, ").opCall(Cin.get);
> 
> D does not specify evaluation order, so the code might end up printing 
> "Hello, " before reading the standard input.

We discussed this a long time ago and came to the conclusion that while 
the D spec does not guarantee evaluation order for this scenario, it 
seems impossible for it to be anything other than left to right because 
the chained calls rely on the return value from previous calls.  If this 
is untrue then I'd love to know the reasoning.  Perhaps an aggressive 
inlining mechanism could violate this?


Sean