Re: gnubol: New bison Grammar available (long)

[Tim Josling <tej@melbpc.org.au>]

RKRayhawk@aol.com wrote:
> 
> Our thinking is different here.  By the way where is Michael when we need him?
> 
> I think the interface to semantics from syntax should be a bludgeon, leaving
> nothing to chance.  It should have explicit begin/end markers, nothing
> implied.  I think of semantics as
> the pen on a drafting device, it needs to be told to lift before moving, or
> we get a line.

Take "if" for example, the tree does very clearly show where the
ends are. So, we have 

01 IF-TREE.
   02  if-tree-test usage pointer. (points to expression to test)
   02  then-statement-list usage pointer (points to linked list
or array of statements)
   02  else-statement-list usage pointer (ditto)

(next sentence doesn't work with this?)

> We tend to think in terms of stacks and linked lists. I think we also tend to
> imagine that we can hold onto these list without much concern for their size
> (that is my stuck record again).

I got some feedback form the gcc list that not everyone has
infinite memory, but my overriding concern is to get it working.
Optimisation has been shown to slow projects down by a factor of
3-4 (See the psychology of computer programming). Plus, lots of
people like tuning. I used to do it full time for a living. Now I
am an architect and I make things run slower.

> And furthermore, holding onto things implies
> an unwillingness to consider a design that can lend itself to parallel
> processes, which I think is a shame.

When you make a large project the compiles will run in parallel
(make -k). Beyond that is a complex optimisation IMHO, slated for
release in the mythical stage II.

> I think the interface should be a well formed document with
> clear tags (no matter how efficiently encoded)

I think the tags are the start and end of the list (null
pointer). Have a look at GCC, (tree.h/.c/.def).

By the way, what time zone are you in (I am trying to work out
when you sleep).

Tim Josling

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