Re: [MIT-Scheme-devel] two changes to push

[Joe Marshall]

On Sat, Sep 19, 2009 at 3:27 PM, Taylor R Campbell <address@hidden> wrote:
>
> I've seen that, but it doesn't say that the declarations can change
> the semantics of a program.  At the very least, it should have a big
> scary warning to say that.  I always assumed that SF would perform the
> transformation only when it could prove that it wouldn't change the
> program's semantics (i.e. only for movable operand expressions).

That's pretty hard to prove unless all the calls between the argument
binding and the argument use are primitives or known to be
effect-free.  For the most part, you can get away with it because
there isn't much Scheme
code that uses side effects.

For SYMBOL?, I thought it was worth integrating because
GUARANTEE-SYMBOL is called on nearly every I/O operation.




-- 
~jrm