.TH PP-ABS 1 "20 April 1992" "Demeter" "Demeter Software"
.SH NAME
pp-abs \- Propagation pattern abstractor

.SH SYNOPSIS

.I pp-abs 
call-graph-file

.SH DESCRIPTION
.I pp-abs
abstracts a propagation directive for a propagation pattern.
.I pp-abs
takes as input a class dictionary extended with a call graph, contained
in the file
.I call-graph-file.
The call graph notation expresses methods attached to classes in a
class dictionary.  The body of a method consists of a number of unique
calls to the same or other methods attached to some class in the class
dictionary. The following example illustrates a class dictionary for prefix
expressions extended with a call graph for the
.I eval
method attached to the classes in the class dictionary.

   Example = PrefixList.
.br
   PrefixList ~ { Prefix }.
.br
   Prefix : Simple | Compound.
.br
   Simple = Number.
.br
   Compound = <op> Op <args> PrefixList.
.br
   Op : AddSym | MulSym.
.br
   AddSym = .
.br
   MulSym = .

   *terminal_sets* Number.

   *implementation*

   Example::eval() *returns* void
.br
   {
.br
     (PrefixList => eval())
.br
   }

   PrefixList::eval() *returns* void
.br
   {
.br
     (Prefix => eval())
.br
   }

   Prefix::eval() *returns* void

   Compound::eval() *returns* void
.br
   {
.br
     (args => eval()),
.br
     (op => eval())
.br
   }

   Op::eval() *returns* void


.I pp-abs
requires the name of the class in the class dictionary from which to
start looking for a propagation pattern, as well as the interface that
defines such propagation pattern. When run,
.I pp-abs
then prompts for the starting class and the file containing the
definition of the interface with the following messages.

Starting at class:
.br
File containing interface definition:

In response to the first message, the user writes the name of a class in
the class dictionary in
.I call-graph-file.
In response to the second message, the user writes the name of a file
containing the definition of an interface as given by class Interface in
the class dictionary in the file $DEMETER/utils/pp-abs/pp-abs.cd.

As output,
.I pp-abs
writes on the standard output a propagation pattern with the given
interface and with a propagation directive that denotes a propagation
graph that contains the call graph given as input.

.SH EXAMPLE

Let us assume that a file named
.I prefix
contains the class dictionary extended with a call graph for the eval
methods illustrated above and let a file named
.I eval
contain the interface for the eval method as follows:

   eval() *returns* void

The following command runs
.I pp-abs:

   $ pp-abs prefix

having the following interaction:

   Adding terminals ...

   Merging graphs ...

   Adding rev alt edges ...

   Computing SCC ...

   Computing propagation frontier ...

   Starting at class:
.I  Example
.br
   File containing interface definition:
.I eval

   Generating propagation graph ...

      Computing SCC ...

      Computing matrix ...

      Computing marks ...

   Connecting propagation neighbors ...

   Computing bypassing edges ...

   Propagation pattern:

   *propagate*
   *interface* void * eval ( )
   *from* Example
   *to* Op

   *** FINISHED ***

Here, the responses to the two prompts,
.I Example
and
.I eval,
are underlined. The output of this example starts with the keyword
.I *propagate*.

.SH FILES

The file $DEMETER/utils/pp-abs/pp-abs.cd contains a class dictionary
describing the class dictionary notation extended with the call graph
notation.

.SH NOTE

.I pp-abs
is an experimental research tool. It is not intended as a final product.
Any suggestions will be considered.


.SH REFERENCES 

.I Abstracting Graph-Based Specifications of Object-Oriented Programs
.br
Ignacio Silva-Lepe
.br
Technical Report NU-CCS-92-4, January 1992