assert(expression, error)

[spir]

On 02/12/2011 02:44 PM, Jonathan M Davis wrote:
> On Saturday 12 February 2011 05:23:06 spir wrote:
>> Hello,
>>
>> Is there a way to specify what error to throw using (a variant of) assert:
>>       assert(n>  0, new ValueError("..."));
>>
>> (Sure, one can write:
>>       if (n<= 0)
>>           throw new ValueError("..."));
>> but the same remark applies to plain assert: the whole point of assert is
>> to have it as builtin feature with clear application field&  well-known
>> semantics, shared by the community of D programmers.)
>
> You mean std.exception.enforce?
>
> assert throws AssertError. Regardless, you probably shouldn't be creating new
> Error types generally. You're _not_ supposed to catch errors and try and handle
> them, so there really isn't any benefit in creating new Error types generally
> anyway. If you want to assert, use assert. Let it be AssertError.
>
> If you want to throw a specific Exception type, and you want it to be a one-
> liner, use enforce. Be aware, however, that enforce is lazy, so any function
> which uses it can't currently be inlined.

All right, thank you for this clear info, Jonathan. (Havn't used enforce yet, 
seems to be cool.)

Denis
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