Hi Doug:

is this a fair description of your idea? If so,
please can you add this to the traversal graph package.

The goal is to make the traversal graph package as good as we can
because it serves as subalgorithm in many different tools here
at NU and outside.

-- Karl
PS. The traversal graph package did very well in our recent testing effort.
    The name map issue is one missing piece which the testing revealed.
===================================================

Based on a discussion with Doug June 10, 1998.

The traversal graph package does not deal with name maps.
There are two name maps to consider:

from strategy graph node names to class valued variables

from class-valued variables to classes

Doug made the following simplifying proposal: Strategy graphs are expressed
in terms of class valued variables. If two nodes are
labeled with same class-valued variable we have a loop
in the strategy graph. 

When we map to classes, we can assign the same class-valued variable to the
same class.

sg: {Expression -> Compound
     Compound   -> SubExpression}

from class-valued variables to classes: SubExpression -> Expression

results in: from Expression via Compound to Expression

The disadvantage of Doug's proposal is that we cannot write
a strategy {A -> B B -> A} without meaning a loop. We would have to write:
{A -> B B -> C} and later C would be mapped to class A.

I like Doug's proposal because it simplifies (no name space
for strategy graph nodes) without giving up much
expressiveness.

An adaptive program should put all its class-valued variables
into its interface. Strategies are written in terms of those
class-valued variables. When a class graph is given:

the strategies are specialized and
the class-valued variables are mapped.

This means that Demeter/Java introduces a name map syntax.

Something like:
NameMap = List(NameMapElement).
NameMapElement = ClassValuedVariable ":" ClassName.
// variables not mentioned are mapped to a class with the same name

The traversal package should take as input a class graph
and a strategy graph and a name map and produce a traversal graph.

-- Karl