[bitc-dev] Problem: mutable literals

[Jonathan S. Shapiro]

On Fri, 2006-05-19 at 20:01 +0100, David Hopwood wrote:
> One possible viewpoint is to consider this to be a problem with 'eq?'.
> If a language only has Henry Baker's 'egal?' operator:
> 
>   Equal Rights for Functional Objects, or The More Things Change,
>     The More They Are the Same
>   <http://citeseer.ist.psu.edu/baker93equal.html>
> 
> then it cannot observe whether a reference to a deeply immutable
> data structure is shared or not.
> 
> The difficulty then is that 'egal?' is not constant time, and sometimes
> (not very often), you really want a constant-time reference equality
> test.

In a systems language, we require that test to be constant time and we
use it pervasively. Further, this isn't a functional language.

shap