At the moment, vppdiff is the only program within vpptool.
Maybe there will be more programs in the future.
The tool vppdiff shows what changed between two Visual Paradigm for
UML (short: VP-UML) project files (names usually ending in ".vpp").
For this, it emits the files' differences on standard output in
unified diff format. If you don't know what this means, read the
section "Unified Diff Format" below.
As vppdiff is written in the Python programming language, you need an
installed Python interpreter. Many Linux distributions have this
already installed. Otherwise you can install Python from the
repositories or download it from http://www.python.org .
Because vppdiff needs the script ExportXMI (ExportXMI.sh on Linux,
ExportXMI.bat [[ExportXMI.cmd?]]] on Windows), you need at least the
Modeler Edition of VP-UML to use vppdiff.
Unified Diff Format
Unified diff format is a textual format used to compare text files.
Though it's usually used for program code, it can be used for most
kinds of text files.
If you compare two files with the `diff` tool which is pre-installed
on many Linux und Unix platforms), you will get something like:
--- vppdiff_test.py 2011-05-01 13:26:07.000000000 +0200
+++ vppdiff.py 2011-05-01 13:25:24.000000000 +0200
@@ -11,11 +11,11 @@
# Namespace for configuration (from command line options and arguments).
First you have a line for each of the compared files. These lines
contain names, date and time of the files. [[What exactly says the
line starting with @@?]] Below that, lines in the first file which are
missing in the second file are prefixed with a "-". Lines which are
missing in the first file and added in the second have a leading "+"
in front of them. Changed lines are denoted by the old version of the
line prefixed with "-" and the new version of the line prefixed with
[[may fail for some XML outputs]]
[[may fail for very large projects which don't fit in memory]]