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Last modified: 14 July 2010

URL: http://cxc-newtest.cfa.harvard.edu/ciao4.2/scripting/index.html

Scripting in CIAO


The CXC is phasing out support for the S-Lang interface in Sherpa and ChIPS - only the Python interface will be supported after CIAO 4.2. This decision was made based on the results of the 2009 CIAO Software Survey.

S-Lang was removed from Sherpa in the CIAO 4.2 Sherpa v2 release (19 July 2010).

New users of CIAO 4 should learn the Python syntax for ChIPS and Sherpa. The CXC is committed to helping existing S-Lang users transition to Python; contact Helpdesk if you need assistance.


The CIAO software offers both Python and S-Lang as user scripting environments. Both software packages are distributed with CIAO, but users may opt to run their own custom installation instead; see "ahelp ciaorc" for information on how to change the Python or S-Lang version that is being used.

The CRATES (S-Lang or Python help) and TRANSFORMS (S-Lang or Python help) libraries provide access to the CIAO Data Model library and a high-level interface for performing World Coordinate System transformations. Access to CIAO's plotting and modeling packages is available through the ChIPS and Sherpa modules.

About S-Lang

S-Lang is a powerful scripting language written and maintained by John E. Davis of the MIT Kavli Institute for Astrophysics and Space Research. It is an interpreted language (which means no compile or link stages) that is used by a number of programs (e.g. ISIS, jed, lynx) as a scripting and control language. S-Lang has a C-like syntax without the worries of memory management and provides a powerful array-based numerical computing environment. Programs can easily add new commands to extend the language.

Refer to the S-Lang Library Information Page for more information.

About Python

Python is a dynamic object-oriented programming language that can be used for many kinds of software development. It offers strong support for integration with other languages and tools and comes with extensive standard libraries. A list of key software features is available on the About Python webpage.

Refer to the Python Programming Language website for more information.


Last modified: 14 July 2010