Purity (D2 standard libraries / object.d)

[Andrei Alexandrescu]

Jason House wrote:
> Walter Bright Wrote:
> 
>> Michel Fortin wrote:
>>> Hum, could the compiler be trusted to add the memoization code to pure 
>>> functions so they can stay pure?
>> If the compiler does general memoization on pure functions, all it has 
>> to do is use the bits of the arguments passed on the stack to the 
>> function as an index into an associative array of the return values.
>>  
>> The problem is identifying if this would be faster than recomputing the 
>> return value.
> 
> What about a compiler hint similar to inline or register?

Maybe making a conscious effort to leave the language feature as a last 
resort action would be better. Creating a memoization feature is a fish, 
creating a language that allows implementing memoization is fishing. :o/

Andrei