[Newcompiler] Properties for AST

[Marcus Denker]

On 09.04.2007, at 15:51, Andrew Tween wrote:


>
> Ok. Thanks.
> I remember a discussion after a UK smalltalk User group meeting  
> last year where
> the question of whether it was better to store source or an AST  
> came up. From
> what I remember, most people thought that storing an AST was  
> better. I made the
> point then that if an AST can be transformed into source, and if  
> source can be
> transformed into an AST, then the two are equivalent, and it  
> doesn't matter
> which is stored except for considerations of memory/disk space, the  
> overhead of
> performing each transformation, etc.
>     If one of these transformations is not ~always~ possible, then  
> some
> information has been lost that it might be beneficial to retain,  
> possibly by
> storing the other representation instead (or store both  
> representations, or a
> third representation).
>
>>
>> I need an AST-like representation, possibly compressed later, for the
>> whole image.
>> Currently the image is 204MB large, our of which way over 100MB are
>> tokens, which are not
>> needed... some information of these is needed, but not the tokens
>> themselves.
>
> Could the source itself be considered to be a compressed  
> representation of the
> AST? ;)
>

Yes... but not when you annotate the AST nodes with things that are  
inherently
non-textual.

Of course you could do some serialization into (non-human-readable)
text, but the question is if it's not better to then searialize the  
objects without caring
about text.
It's a bit a "point of view" question: How do I think about the  
system, and
do I restrict my thinking by forcing myself to be text only?

As I said: maybe in the end, people will not like it. In most  
languages Classes
are not objects, too, as you can parse the code on demand like  
eclipse does....
And people love it.

Same problem, same solution. Smalltalk opted to model Classes as  
object, with
no source level representation at all. I think we should do the same  
for methods.

	Marcus


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