Compile time function execution...

[Walter Bright]

Michiel wrote:
> Walter Bright wrote:
> 
>> Many functions could be executed at compile time, but should not be.
> 
> When should they not be?

1) Another poster mentioned a function that decompressed a built-in 
string - the whole point of having it compressed was to reduce the exe 
file size. Decompressing it at compile time defeats the purpose.

2) A function that simply takes too long at compile time. Compile time 
execution is going to be >100 times slower than run time.

3) As the spec mentions, there are cases where compile time would get 
different results than run time.

4) The compiler cannot determine in advance if a function can be 
executed at compile time. So speculatively doing so would have to be 
done for every function with constant arguments - this could be 
spectacularly slow.

5) It can cause problems for people who want to do runtime coverage 
testing - their code may actually never get executed, and they never notice.