Why exceptions for error handling is so important

[Russel Winder via Digitalmars-d]

On Mon, 2015-01-12 at 11:32 -0800, Andrei Alexandrescu via Digitalmars-d wrote:
> On 1/12/15 11:30 AM, Russel Winder via Digitalmars-d wrote:
> > 
> > On Mon, 2015-01-12 at 10:43 -0800, H. S. Teoh via Digitalmars-d 
> > wrote:
> > > 
> > […]
> > > And what exactly should operator[] return if a key wasn't found?
> > > 
> > […]
> > 
> > Go has an interesting solution, key lookup in a map return a pair 
> > (result, ok), if lookup succeeded then result is the associated 
> > value, if ok is false then result is undefined. I quite like this.
> 
> How can you like undefined? That's a terrible solution again 
> underlining
> Go's conflation of union and product types. -- Andrei

They may be fiddling with type systems, but I was wrong about 
undefined: if the key is not found then lookup returns the zero value 
for the value type. Given this is useless to me, I think in terms of 
it being undefined, which is technically wrong, but good for my code.
-- 
Russel.
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