====
    Copyright 2009 Humboldt-Universität zu Berlin, INRIA.

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

          http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.


====
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* Pepper is a Salt model based converter for a variety of linguistic formats.                                          *
* For further information, visit: http://corpus-tools.org/pepper/                                                      *
* For contact write an eMail to:  saltnpepper@lists.hu-berlin.de                                                       *
* Version of Pepper:              3.4.1                                                                       *
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 If you need to convert corpora from one linguistic format into another, Pepper is your swiss-army knife. When your 
annotation tool produces a different data format from the one your analysis tool can read, Pepper is there to the 
rescue.

* Pepper can convert documents in a variety of linguistic formats, such as: EXMARaLDA, Tiger XML, MMAX2, RST, TCF, 
  TreeTagger format, TEI (subset), ANNIS format, PAULA and many many more.
* Pepper comes with a plug-in mechanism which makes it easy to extend it for further formats and data manipulations.
* Pepper is module-based, each mapping is done by a separate module. This enables each module to be combined with 
  every other module in one single workflow.
* Pepper uses the intermediate model Salt, which reduces the number of mappings to convert n into m formats.
* Pepper modules, such as the MergingModule, allow to merge the data from different annotation tools together and create 
  multi-layer corpora.
* Pepper can be used as an interactive command line tool, as a command to be included in scripts, or as an API to be 
  integrated in other software products.
* Pepper is written in Java and can be run on all operation systems which are ready to run Java (Windows, Mac, Linux, 
  Unix, ...).
* Pepper is free and open source software. It is distributed under the Apache License, Version 2.0.

 To decrease the number of conceptual mappings, Pepper uses an intermediate model, which means that a conversion 
consists of two mappings. First, the data coming from format X will be mapped to the intermediate model Salt and second,
the data will be mapped from Salt to format Y. If you imagine a set of n source and target formats, this approach will 
decrease the number of mappings from n²-n mappings in case of a direct mapping approach, to 2n mappings. 

 Pepper itself is a platform controlling the workflow of a conversion process. The mapping itself is done by a set of 
Pepper modules. Pepper is a highly pluggable platform which offers the possibility to plug-in new modules in order to 
incorporate further formats. The flexible architecture of Pepper allows to combine all existing modules and to easily 
plug in new ones. 

===============
Pepper Workflow
===============
 The conversion process in Pepper is defined by a workflow. Such a workflow is normally stored in an xml file and is 
separated into three different phases:

* the import phase (mapping data from a given format to Salt),
* the optional manipulation phase (manipulating or enhancing data in Salt) and the
* export phase (mapping data from Salt to a given format).

 The three-phase process makes it feasible to influence and manipulate data during conversion, for example by adding 
additional information or linguistic annotations, or by merging data from different sources. The import phase handles 
the mapping from a format X to Salt, the export phase handles the mapping from Salt to a format Y. During the 
manipulation phase, the data in Salt can be enhanced, reduced or manipulated. A phase is divided into several steps. 
The import and export phase must contain at least one step each, whereas the manipulation phase can contain any number 
of steps. Each Pepper module realizes exactly one step. 

 A Pepper module can be identified by specifying its name or the format's name and version of the corpus to be 
converted. For instance the import of data in the EXMARaLDA format is done by a module called EXMARaLDAImporter and the 
export into the ANNIS format is done by a module called ANNISExporter. The orchestration of Pepper modules can be 
persisted by the Pepper workflow description file (.pepper). The modules can be freely combined, e.g., we can exchange 
the EXMARaLDAImporter with the TigerImporter and still export the data to ANNIS. But you have to take care, that the 
target format can handle those data, otherwise they will be ignored. For instance converting data coming from the Tiger
format to EXMARaLDA does not make a lot of sense, since EXMARaLDA can not handle syntax trees. Nevertheless, even such 
transformations are allowed in Pepper.

 A Pepper workflow can get very complex, for instance when multiple source formats are included, a long manipulation 
chain is used and/or the data shall be exported to multiple formats at once.A Pepper workflow can be stored to a xml 
file. The structure of a workflow file is described in workflow file. Some real life workflows can be found under
http://corpus-tools.org/pepper/demos.html. 

============
Run Pepper
============

To run Pepper open a command line and enter (for Windows):
* pepperStart.bat COMMAND

or (for Linux, Unix and Mac OS):
* bash pepperStart.sh COMMAND

Now Pepper starts the interactive command line and welcomes you with the prompt
* pepper>

To get a list of all available commands, enter 'help':
* pepper>help

To get a list of all available modules, enter 'list':
* pepper>list

To start a conversion with a predefined workflow, enter 'convert' followed by the workflow description file:
* pepper>convert myConversion.pepper

To start the interactive conversion wizard, which helps you to define a workflow description, enter just 'convert':
* pepper>convert

============
Conversion Wizard
============
 To run a conversion process with Pepper, you need to define, which modules should be used. This is usually done in a 
workflow. Remember, the Pepper workflow is separated into three different phases: the import phase (mapping data from a 
given format to Salt), the optional manipulation phase (manipulating or enhancing data in Salt) and the export phase 
(mapping data from Salt to a given format).

 The conversion wizard should help you to create a Pepper workflow, but you can also create such a workflow in an xml 
file as described in workflow file. The wizard will guide you step by step through the creation of a workflow and will 
let you store the created workflow to disk when you are done. Enter the path of the corpus to import e.g. 
'C:\myCorpus\':

* pepper/wizard/importer>C:\myCorpus\

Now Pepper displays a list of all available importers and asks you to choose one of them.

+------+-------------------------------+------------------------------------------+
| no   | module name                   | format                                   |
+------+-------------------------------+------------------------------------------+
| * 1  | TextImporter                  | (txt, 0.0)                               |
|   2  | SaltXMLImporter               | (SaltXML, 1.0)                           |
|   3  | DoNothingImporter             | (doNothing, 0.0)                         |
        

 A '*' next to the number of the importer shows, that this importer is recommended. Recommended means that the passed path 
contains files in a format the importer is able to process. To choose an importer, just enter its number or its name.

* pepper/wizard/importer>1

 Some importers provide a list of properties to customize the import. If this is the case, Pepper displays a list of all 
available customization properties.

+----+-------------------------------+------------------------------------------+
| no | property name                 | description                              |
+----+-------------------------------+------------------------------------------+
| 1  | pepper.before.addSLayer       | Consumes a semicolon separated list of   |
|    |                               | names for {@link SLayer} objects. For    |
...
        

To use a property, enter its number or name, followed by '=' and the value of the property.

* pepper/wizard/importer>1=anyValue

 Pepper keeps asking you to enter further customization properties until you enter an empty line.
Since it is possible to use more than one importer for one workflow, Pepper asks you to enter a further corpus path. To 
skip that just press 'enter'. In Pepper you have the possibility to manipulate the data between the im- and the export 
phase. Therefore Pepper displays a list of all available manipulators and asks you to enter the number or name of a 
manipulator. To skip adding a manipulator just press 'enter'. Also, manipulators can be customized. When the chosen 
manipulator provides properties for customization, Pepper displays them and asks you to enter such a property. To skip 
adding further manipulators just press 'enter'. Finally, choose an exporter. Pepper shows a list of all available 
exporters. To choose one of them enter its number or its name. Again you have the chance to customize the export by 
adding some customization properties, if provided. To do so, enter the number or name of a property followed by '=' 
and the value. Along with importers and manipulators, you can add more than one exporter. To stop adding exporters, 
enter an empty line.To save the workflow, enter 'save' followed by a path where to store the file (.pepper).

* pepper/wizard>C:\myCorpus\myWorkflow.pepper

 A workflow file is stored as an xml file and is structured as described in workflow file.
To start the conversion enter 'start'.

* pepper/wizard>start

To exit and abort the conversion, enter 'exit'.

==================
Configuring Pepper
==================

The Pepper home folder contains a folder named 'conf/', here you find two files to adapt the behavior of Pepper. First 
you can change the logging behavior by adapting the file logback.xml. The default configuration is configured using the 
INFO log level:

<root level="info">
   ...
</root>

A log level determines which types of log messages are printed. The hierarchy is the following (ascending): trace, 
debug, info, warn, error. That means, when setting the log level to info, warn and error messages are printed, but no 
trace and debug messages.

Secondly, by adapting the file 'pepper.properties' you can change the processing behavior of Pepper. This file has a 
key-value notation, which mean an entry has a key, followed by the equal sign and the corresponding value. Here is an 
excerpt of that file:

##########
# Determines where to find the plugins for Pepper $PEPPER_HOME points to the pepper home folder (this is not an 
# environment variable)
##########
pepper.plugin.path=./plugins/

##########
# Determines if Pepper shall measure and display the performance of the used PepperModules
##########
pepper.computePerformance=true

##########
# The maximal number of currently processed SDocument-objects
########## 
pepper.maxAmountOfProcessedSDocuments=4

##########
# Determines if an SDocument-object shall be removed after it was processed by all PepperModules
########## 
pepper.removeSDocumentAfterProcessing=true
	


=============
Workflow File
=============

In Pepper you have the chance to store a workflow in a workflow file (.pepper). This allows you to redo and reuse a 
configured workflow. You can also add this file to a version control system, to persist the details of how a corpus was 
processed. A workflow is stored in an xml file following the Pepper scheme. A workflow consists of three phases: import 
phase, manipulation phase and export phase. The notation of the workflow file follows this structure. To identify a 
Pepper module realizing a step, you have to describe that module by its name or the format's name and version. The 
following sample consists of three steps, one importer, one manipulator and one exporter:

<?xml version="1.0" encoding="UTF-8"?>
<?xml-model href="https://korpling.german.hu-berlin.de/saltnpepper/pepper/schema/10/pepper.rnc" 
            type="application/relax-ng-compact-syntax"?>
<pepper-job version="1.0">
	<importer formatName="FORMAT_NAME" formatVersion="FORMAT_VERSION" path="SOURCE_PATH">
		<customization>
			<property key="PROPERTY_NAME">PROPERTY_VALUE</property>
		</customization>
	</importer>
	<manipulator name="MANIPULATOR_NAME">
		<customization>
			<property key="PROPERTY_NAME_1">PROPERTY_VALUE</property>
			<property key="PROPERTY_NAME_2">PROPERTY_VALUE</property>
		</customization>
	</manipulator>
	<exporter name="EXPORTER_NAME" path="TARGET_PATH"/>
</pepper-job>
        

The importer - in contrast to the exporter - is identified by the format's name (FORMAT_NAME) and the format's version 
(FORMAT_VERSION). The exporter and the manipulator are identified by the module names (MANIPULATOR_NAME and 
EXPORTER_NAME). To customize the workflow, some modules provide a set of properties. A property consists of a name-value 
pair. A description of properties can be found on the modules site or when entering the command 'list' followed by the 
module name in the pepper console, for instance:

pepper>list MANIPULATOR_NAME

An importer and an exporter need a source or a target path to address where to find the corpus or where to store it. 
Such a path can be addressed relative or absolute. A relative path can start with './' for current directory or '../' 
for the parent directory, for instance:

./corpus

or

../corpus

An absolute path could start with the file scheme, e.g.:

file:/C:/format1/corpus1/

or

file:///C:/format1/corpus1/

or without any scheme:

C:/format1/corpus1/

