Re: Optimization techniques and runtime checks

Am 07.05.2019 um 16:29 schrieb David Brown:
> On 29/04/2019 22:36, Hans-Peter Diettrich wrote:
>> Am 28.04.2019 um 23:49 schrieb David Brown:


>>> This is exactly the same as mathematics. The "square root" function,
>>> for real numbers, is defined for non-negative numbers. If someone asks
>>> you for "sqrt(-4)", then the question is meaningless. Any answer given
>>> can be considered incorrect - equally, any answer given can be
>>> considered correct.
>>
>> That's a cheap excuse for poor language design, aimed at sloppy compiler
>> implementation.
>>
>
> You are saying that mathematics is a poor language design?


No, I criticize the lack of restricted (non-negative...) types for such
purposes.




> Different languages have different purposes and trade-offs. This is
> important to accept when discussing them.


No doubt :-)


So I wonder why the topic (optimization...) drifted into a discussion of
almost only the C language.


I also wonder where runtime efficiency nowadays is really so important,
that safety and security breaches are considered acceptable?




> Every language has its oddities, and there are always things that some
> people thing are terrible design. For example, it is truly weird that
> "const x : int = 10;" is one of Delphi's way of making "x" a variable
> with an initialised value. (In older Delphi, it was the only way!)


This makes the different evolution visible:
Pascal started as a tutorial language, C as a production language.
Evolution added features of great demand - in the case of Pascal many
features had to be added to Wirth's academic language(s) before it
became usable outside education.


I definitely prefer a safe language, which can be tuned later for
efficieny. Lowering requirements and checks in specific parts of a
program is doable and acceptable easier than introducing requirements
that were not anticipated in the basic language design.


DoDi
[These days I write just about everything in python. Occasionally
I'll rewrite something in C if python can't do it but that's pretty
rare. The python implementation everyone uses is written in C but it
does a pretty good job of managing storage and arithmetic. -John]

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