Why exceptions for error handling is so important

[Walter Bright via Digitalmars-d]

On 1/12/2015 6:57 AM, Martin Nowak wrote:
> The general solution in functional programming is error chaining.
> An example, C is a function that reads in lines of a program and B is a function
> that takes all those lines and counts words.
> C will either return an error or lines and B will either immediately return that
> error to A or convert the lines to word counts.
> This works especially well with function chaining, because you can hide the
> error propagation in a generic chaining method (called map).
>
> http://danielwestheide.com/blog/2012/12/26/the-neophytes-guide-to-scala-part-6-error-handling-with-try.html


Yes, it still appears to be just a wrapper around returning two values, and that 
has to be done for everything.

There's another downside to returning two values - extra code is generated, and 
it consumes another register. It allocates very scarce resources to rare cases - 
not a recipe for high performance.