Hi Thorsten,
> > (while (read) (println @)) ) )
> >
> > This gives one top-level expression per line which can be easily
> > 'regexp'ed.
>
> Thats a nice tip, thanks ... not that I understand it, the magic must be
> in the (println @), right?
Yes. 'println' prints one or more expressions and a newline, without any
further formatting. So if you 'read' an expression like
(a
(b
(c d
(e f) ) ) )
it will be printed as
(a (b (c d (e f))))
> ,------------------------------------------------
> | (rel exp (+Class1 +Class2 ...) {xxx} (+Class3))
> `------------------------------------------------
>
> My real question was what can happen in the {xxx} part above (just from
> the point of view of parsing the section with regexp:
>
> - {empty}
> - NIL
> - sym
> - (list) sym
> - ... ?
Yes depending on the class(es) in the relation type (the first list). It
may also be a number (e.g. for '+Number' (an optional scale) or '+Snx'
(the minimum string length)).
'+Link' takes a type (a list of classes), while '+Joint' as an extension
to '+Link' takes an additional symbol (the slot in the "opposite"
object).
> So it will probably been shown as a bidirectional association:
>
> ,------------------------------------------
> | (rel ord (+List +Joint) pos (+Ord))
> `------------------------------------------
>
> one-to-many?
>
> ,------------------------------------------
> | (rel ord (+Joint) pos (+Ord))
> `------------------------------------------
>
> one-to-one?
These two lines cannot be seen independently. Together, they describe a
1-to-N relation.
If you just see
(rel ord (+Joint) pos (+Ord))
it may be a 1-to-1 or a 1-to-N, depending on the opposite side.
Note that also
(class +Cls1 +Entity)
(rel var1 (+List +Joint) var2 (+Cls2))
...
(class +Cls2 +Entity)
(rel var2 (+List +Joint) var1 (+Cls1))
is possible, describing a N-to-N relation.
> >> ,-----------------------------------
> >> | (rel pos (+List +Bag) # Positions
> >> | ((+Ref +Link) NIL (+Item)) # Item
> >> | ((+Number) 2) # Price
> >> | ((+Number)) # Quantity
> >> | ((+String)) # Memo text
> >> | ((+Number) 2) ) # Total amount
> >> `-----------------------------------
>
> I think I'll have to figure out a trick how to deal with bags, way to
> much effort to get all this info into an UML diagram.
Perhaps (+List +Bag) can be seen as an object-local "table"?
> BTW, one more question:
>
> The vars sometimes specified in the comment beyond a class definition:
>
> ,-----------------
> | (class ...
> | # var1 var2 var3
> | ...)
> `-----------------
>
> can be considered as a kind of 'private instance (or class) variables?
Yes. I would not use "private" here, as it sounds like information
hiding, which is not the case.
"Instance variables" fits best. BTW, there are also "class variables"
(http://software-lab.de/doc/refV.html#var).
♪♫ Alex
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