[OT] The Usual Arithmetic Confusions

[forkit]

On Friday, 18 February 2022 at 05:47:13 UTC, Paul Backus wrote:
>
> The behavior of converting a uint to an int is well-defined in 
> D: the uint's bit pattern is re-interpreted as a signed int 
> using 32-bit two's complement notation. This conversion is 
> valid for every possible pattern of 32 bits, and therefore for 
> every possible uint. There is absolutely no possibility of 
> undefined behavior.
>
> "Undefined behavior" is a technical term with a precise 
> meaning. [1] It does not simply mean "undesirable behavior" or 
> "error-prone behavior" or even "behavior that violates the 
> rules of conventional mathematics."
>
> [1] https://en.wikipedia.org/wiki/Undefined_behavior

The 'convertability' of a type may well be defined by the 
language, but the conversion itself may not be defined by the 
programmer.

I don't think it is unreasonable, to extend the concept of 
'undefined behaviour' to include behaviour not defined by the 
programmer.

But in any case...semantics aside...

In a language that does implicit conversion on primitive types, I 
would prefer that the programmer have the tools to undefine those 
implicit conversions.

That is all there is to my argument.