default XML value proposal

Hi folks,

I've been working on implementing XMILE and have run into a few minor snags.

First, there is an idea that attributes have a default value.  I would like to propose that all default attributes for numbers and booleans be 0/false.  My implementation uses reflection to marshal XML into structures - it becomes hard to tell if an attribute was explicitly specified with a 0-value, or was omitted in the XMILE file in some parts of the current spec.  I think that changing options from, e.g. 'show_background' (with a default of true), to 'hide_background' (with a default of false) will make implementations easier and lower the cognitive load when visually inspecting XMILE files.  This idiom appears most often in the <display> tags, but is sprinkled elsewhere too (such as an aux's flow_concept=true).

Without this, it becomes very difficult to build a parser for XMILE without hand-coding the XML read/write.

I'll have more to share in a few days, but thoughts and concerns about the above are welcome.

yours,

Bobby