purity question

[Era Scarecrow via Digitalmars-d-learn]

On Sunday, 28 May 2017 at 23:49:16 UTC, Brad Roberts wrote:
>     // do something arbitrarily complex with s that doesn't 
> touch globals or change global state except possibly state of 
> the heap or gc

  Sounds like the basic definition of pure to me; At least in 
regards to D. Memory allocation which is a system call, doesn't 
actually break purity. Then again if you were worried about not 
using the gc, there's the newer nogc property.

[quote]
  TDPL pg. 165: 5.11.1 Pure functions

  In D, a function is considered pure if returning a result is 
it's only effect and the result depends only on the function's 
arguments.
[/quote]