[Coldstuff] Some undocumented functions

[Bruce Mitchener]

The description below maches my understanding.  I don't like that 
inherited_var uses a different search order than method lookup though. 
It is also somewhat slower than method stuff as inherited_var() isn't 
cached (obviously) and can require more intermediate objects to be 
loaded in the search for a value.

And then to explain more of why I don't like them, I'd have to get into 
how I wish Cold had an 'unbound' value for the default value rather than 
0 .... *sigh*

Good night.

  - Bruce

Brad Roberts wrote:
> I'll let Bruce, Brian, or Brandon correct any errors in this, so don't
> take it as gospel until someone backs me up.
> 
> get_var('variable)
> default_var('variable)
> inherited_var('variable)
> 
> All three take a symbol that is the name of the variable to lookup.  All
> three will throw ~varnf if the variable isn't declared on the parent that
> contains the method being executed.  All three return the value of that
> variable as contained in the child object, if it exists.  Where they
> differ is in what they do if the child object doesn't have a value yet.
> 
> get_var returns 0.
> 
> default_var returns the value of the variable on the parent (it will
> always have a value, though it might be 0 also).
> 
> inherited_var walks up the parent tree (in breadth first order) and
> returns the value from the first parent to have a value.
> 
> So.. that's the short form of the docs for these three builtin functions.
> The latter two rather break one of the fundamental tenet in cold's
> object system, strong variable encapsulation.  That said, coldcore uses
> default_var in 3 places, all of which could have easily been done without.