std.unittests [updated] for review

[Andrei Alexandrescu]

On 2/1/11 11:29 AM, Jonathan M Davis wrote:
> On Tuesday 01 February 2011 09:12:16 Andrei Alexandrescu wrote:
>> On 2/1/11 10:51 AM, Michel Fortin wrote:
>>> On 2011-02-01 11:31:54 -0500, Andrei Alexandrescu
>>> <SeeWebsiteForEmail at erdani.org>  said:
>>> TypeInfo holds a pointer to the toString function, so if the compiler
>>> passes the two operands as D-style variadic arguments to the assert
>>> handler, the assert handler can use toString to print them. The operator
>>> should be passed as a string.
>>
>> In that case problem solved. Don, if you arrange things such that this
>> user-level code:
>>
>> int a = 42;
>> double b = 3.14;
>> assert(a<= b, "Something odd happened");
>>
>> ultimately calls this runtime function:
>>
>> assertCmpFailed("<=", "42", "3.14", "Something odd happened");
>>
>> I promise I'll discuss with Sean and implement what it takes in druntime
>> to get that completed.
>>
>> We need to finalize that before Feb 7 though because on that date the
>> vote for Jonathan's library closes. If you do implement that, probably
>> we'll need to reject the library in the current form and propose back an
>> amended version.
>
> You do need to remember to take into account though that expressions can be
> quite a bit more complex than a<= b, and you still want to be able to print out
> something useful.
>
> It's been discussed a bit already, but IIRC what appeared to be the best
> solution was that when an expression evaluated to false, you take the expression
> to evaluated and stop evaluating it when all that was left is operators or
> functions which resulted in bool. Then the value of those operands would be
> printed. e.g.
>
> assert(min(5 + 2, 4)<  2&&  max(5, 7)<  10);
>
> would print out the values
>
> 4, 2, 7, and 10.

It's all about the top-level AST node. In this case I think it's 
reasonable to print "false && __unevaluated__" or simply "false". If the 
user wants the separate values, they can always write:

assert(min(5 + 2, 4) <  2);
assert(max(5, 7) <  10);

> and
>
> assert(canFind("hello world", "goodbye"));
>
> would print out the values
>
> "hello world" and "goodbye".

I guess again taking the function call as the top node, assert could 
print the arguments passed into the function.


Andrei