[e-lang] Re "Rapid Case Dispatch in Scheme"

[Kevin Reid]

 From our discussion <http://meme.b9.com/cview.html? 
channel=erights&date=060928>:

> 05:46:56 <markm_> http://scheme2006.cs.uchicago.edu/07-clinger.pdf  
> - "Rapid Case Dispatch in Scheme" by Clinger
...
> 06:51:36 <kpreid> markm: the case dispatch paper seems not to cover  
> implementation details of the clause index to code part
> 06:52:01 <kpreid> true or did I miss something?
> 06:52:06 <kpreid> the "Related Work" section seems to list  
> everything they *don't* do
> 06:52:21 <markm_> I'll have to take a closer look soon. (I've only  
> skimmed so far.)


I have now found the part I was missing in the paper:

> 2. Implementation
> ...
> The basic idea can be seen in figure 1:
> ...
>   3. Use binary search on the clause index to select the  
> expressions to be evaluated for that clause.

This can be seen in the code in figure 3, but in a sufficiently  
simple form that I didn't recognize it:

(if (<:fix:fix n 1)
     (f-other x)
     (if (<:fix:fix n 2)
         (f-vowel x)
         (f-consonant x)))

That is, a binary search with all branches written out explicitly.

-- 
Kevin Reid                            <http://homepage.mac.com/kpreid/>