Do we really need const?

[Regan Heath]

Bill Baxter wrote:
> Matti Niemenmaa wrote:
>> Bill Baxter wrote:
>>> There's of course Java.  Lots of enterprise software is written in Java,
>>> and yet Java does not have const.
>>
>> Java has a limited form of const in final, which allows for both 
>> compile-time
>> constants and variables which can only be assigned to once.
>>
>> See the "variables" and "fields" sections here:
>> http://renaud.waldura.com/doc/java/final-keyword.shtml
> 
> Yes, a lot of languages seem to have that form of const, which is more 
> or less like const is in D1.x.  That doesn't seem to be the problematic 
> kind.

Java also has invariant strings which is another form of const, one that 
makes multithreading easier.

It seems that there are at least 4 forms of const:

1. invariant data
2. invariant variables
3. logical const
4. transitive const

Forms #1 and #2 should combine well with 'pure' I imagine.

Regan