Re: [boost] [Boost Review] Property Tree Library

From: Marcin Kalicinski (kalita_at_[hidden])
Date: 2006-04-19 13:07:42

> Two things that I had to roll into my config system:
> a) ability to include other files

This is a parser job to handle includes. Of the parsers included with the 
library only INFO supports them, but I believe other formats (XML, JSON, 
INI) do not have a notion of include at all.

> b) inline variable expansion, e.g.
> site.root = c:\dev
>       site.home = ${site.root}\home

Yeah, long time ago the library supported that. There are actually 2 types 
of "dynamic values", or inline-expanded values as you call them:
1. Values which are expanded statically during parsing
2. Values which are fully dynamic - i.e. lookup is performed everytime you 
access the value (so if you change the original, the dependent changes as 
well).

#1 is just a parser issue - something along the lines of statically expanded 
entity references in XML. #2 requires support infrastructure from the 
basic_ptree class - namely a pointer to parent. And a way to describe 
relative paths, so more extra characters would be needed than just the 
separator.

> What are your thoughts on this being included in your library?
> Anyone else need to do this type of stuff, or would find this useful?

If there is enough interest I may try to revive it. On the other hand, a 
better solution might be to build another class on top of ptree that 
supports dynamic values.

Marcin