.TH CD-ABSTRACT 1 "15 October 1993" "Demeter" "Demeter Software"
.SH NAME 
cd-abstract \-\- abstracts the common structure between two class dictionaries.

.SH SYNOPSIS
.B
.I cd-abstract 
[class-dictionary1] [class-dictionary2]

.SH DESCRIPTION
.I cd-abstact 
returns the maximal class dictionary of which both
.I class-dictionary1
and
.I class-dictionary2
are extensions; that is, the returned class dictionary contains all the
similarities between the two given class-dictionaries. The default names for
.I class-dictionary1
and
.I class-dictionary2
are demeter-input and demeter-input2, respectively.


.SH EXAMPLES
To abstract between two given class-dictionaries:
      example% .I cd-abstract 
cd1 cd2

.SH WARNING
The class-dictionaries have to be flat; that is, they have to be in ANTI_CDCNF.

.SH REFERENCES
.I User's Guide for the Demeter System/C++
.br
Walter L. Hursch
.br
Northeastern University, 1993

.I Object-Oriented Schema Extension and Abstraction
.br
Walter L. Hursch, Karl J. Lieberherr, Sougata Mukherjea
.br
In Symposium on Applied Computing, Indianapolis, Indiana, February 1993, ACM
Press.