[kepler-dev] [Bug 1543] - create workflow scripting language

[bugzilla-daemon@ecoinformatics.org]

http://bugzilla.ecoinformatics.org/show_bug.cgi?id=1543





------- Additional Comments From cxh at eecs.berkeley.edu  2004-05-03 14:34 -------
Ptolemy II includes Jacl, which is a 100% Java implementation of a 
subset of Tcl.  We use Jacl for the test suite.  Tcl is fairly easy
to pick up, and there are plenty of examples about how to run models.
There is some documentation about Jacl at
http://ptolemy.eecs.berkeley.edu/ptolemyII/ptII4.0/ptII4.0-alpha/doc/coding/testing.htm

Another language to look at is Jython, which is a Java implementation
of a subset of Python.  There is also a Python script actor that
might be useful. See 
http://www.jython.org/

I think Python probably has a larger user community than Tcl these days.
Both Jacl and Jython are not really being actively developed, which is 
good in that they are not wildly changing over time.  I've been fixing
bugs in the Ptolemy copy of Jacl, and there is als a Sourceforge TclBlend/Jacl
project.  Last I looked, Jython had not been updated in a couple
of years, but we recently recompiled Jython to solve a Java 1.5 runtime
problem.

Another language to look at is Caltrop, which is a language that also shipped
with Ptolemy II:
 "Its research focuses on the definition of CAL, a textual notation for writing
dataflow actors, and uses and applications of that language inside and outside
of Ptolemy and the Ptolemy II software."

Ptolemy II uses JavaCC in several places, but you might want to look
at using CUP and JFlex instead of JavaCC.  Basically, using JavaCC  
as a LL parser can result in ambiguities as a language grows.  I'm 
told, and I vaguely remember, that LALR parsers such as CUP/JFlex tend
to have fewer problems with ambiguity.

One trick we use when defining models in Java is to add an exportMoML()
call.

For example, ptolemy/domains/sdf/demo/OrthogonalCom/OrthogonalCom.java
says:
            // Uncomment the next line dump out xml.                            
            // System.out.println(exportMoML());  
One can do similar things in Jacl and presumably Jython as well.               
              

Basically, I encourage you to look at an off the shelf language and see 
if you can use it.  One trick is to define some utility procedures to
do common tasks.  For example, in Ptolemy II, we have Tcl code in 
$PTII/util/testsuite that defines sdf and de models.  These utility
methods are used to set up models for testing.

-Christopher