Re: [boost] Interest in DSL framework

From: Joel de Guzman (joel_at_[hidden])
Date: 2006-08-11 18:37:47

Andreas Pokorny wrote:

>> I guess I'm still not clear about "attributes". What are those, really?
>> And why will attributes not work with segmented sequences? or not
>> required?
> 
> An attribute is a compile time or compile time and runtime information
> stored for an expression tree, and identified by a key type. 
> 
[snip example]
> 
> This information is stored inside a container and wrapped inside key-value pairs, to 
> be able to write generic rules. Rules not coupled to the attribues they process. 
> So rule can simply take all attributes of either operands and combine them where possible,
> or update their values/types if required and store the results inside the expression 
> encoding data structure returned by the rule. 
> 
> To define an attribute one needs a key type, and some meta functions which get called by 
> the rule, e.g. if an attribute occurs on both operands of a node, a combine meta function 
> is called. 
> 
> My statement about attributes and segmented sequences is probably wrong. Attributes just 
> need a fusion::map and rules that invoke the automated attribute processing. 

Ah! Pretty cool!

Regards,
-- 
Joel de Guzman
http://www.boost-consulting.com
http://spirit.sf.net