Re: [gobo-eiffel-develop] Gobo Eiffel parser: indexing and assertion expressions

[Eric B. <er...@go...>]

Martin Piskernig wrote:
> I have another question (I just started to use the Gobo Eiffel parser 
> some days ago, please be patient with me...).
> 
> Why is ET_CLASS.first_indexing and ET_FEATURE.first_indexing always 
> Void? Did I forget to do some parsing? The classes and features 
> themselves all show and can be processed nicely, only they seem to have 
> absolutely no indexing... 

When parsing, you need to use an AST factory of type
ET_DECORATED_AST_FACTORY instead of ET_AST_FACTORY.

> The same is true for assertion expressions, be it preconditions, 
> postconditions or invariants: ET_ASSERTION.expression is always Void 
> (on the other hand, i can use ET_TAGGED_ASSERTION.tag without 
> problems). 

Because of ambiguities in the syntax, it is possible that
an assertion of the type:

     tag: expression

ends up in the AST as two assertions nodes: one the tag
and one for the expression.

> btw: Is there an easy way to convert an expression to a string 
> representation? I would need to output assertions...

If you used ET_DECORATED_AST_FACTORY with `keep_all_breaks'
set to True, then you can use ET_AST_PRINTER to print the node
as it was in the text file. Otherwise, you can also use
ET_AST_PRETTY_PRINTER, or inherit from one of those to
customize your own printer.

-- 
Eric Bezault
mailto:er...@go...
http://www.gobosoft.com