[kepler-dev] references to Java properties from within StringParameter entry fields

[Christopher Brooks]

Hi Tim,
Try using a regular parameter instead of a parameter in string mode.

StringParameter extends Parameter, Parameter extends Variable.
StringParameter merely calls setStringMode(), which Variable
uses to determine which parser is used.

PtParser.jjt says:

    /** Generates a parse tree from the given String, which is interpreted
      *  in "String Mode" instead of as an operator expression.  In
      *  string mode, the expression is a literal string, except for
      *  identifiers which are denoted by $param.  The root node is
      *  returned. To evaluate the parse tree, use a ParseTreeEvaluator.
      *  @param stringIn The expression to be parsed.
      *  @exception IllegalActionException If the parse fails.
      *  @return The root node of the parse tree.
      */
     public ASTPtRootNode generateStringParseTree(String stringIn)

So, what you want is a regular Parameter, which should expand
property() properly.

_Christopher

Timothy McPhillips wrote:
> Hi Christopher,
> 
> Is there a convenient way to access the values of Java properties from 
> within the entry field for a StringParameter?
> 
> For a plain Parameter it appears one can refer to Java properties in 
> this manner:
> 
> Image:  
> property("KEPLER")+"/demos/getting-started/species-distribution.jpg"
> 
> But this requires using quotes to signify a string value.  In a 
> StringParameter one can refer to the values of other Variables in scope 
> (e.g., a Parameter defined on the workflow canvas) using the $ symbol, 
> and no quotes are needed.  For example, if I define a Parameter on the 
> canvas named 'Directory' that refers to the value of the Java property 
> 'COMAD_TESTS':
> 
> Directory:  property("COMAD_TESTS")
> 
> ..then in a StringParameter of an actor on that canvas I can refer to 
> the value of that Directory parameter:
> 
> File:  $Directory/test-files/TestCollectionReader_new.xml
> 
> What I can't seem to do is refer to the Java property directly in the 
> entry for the StringParameter, e.g. entering
> 
> $property("COMAD_TESTS")/test-files/TestCollectionReader_new.xml
> 
> gives the exception:
> 
> ptolemy.kernel.util.IllegalActionException: Error evaluating expression: 
> $property("COMAD_TESTS")/test-files/TestCollectionReader_new.xml
>   in .TestCollectionReader_test.CollectionReader_New.File
> Because:
> The ID property is undefined.
> 
> 
> Is there an easy way to do this?
> 
> Thanks!
> 
> Tim
> 
> 
> 
> 

-- 
Christopher Brooks (cxh at eecs berkeley edu) University of California
CHESS Executive Director                      US Mail: 337 Cory Hall
Programmer/Analyst CHESS/Ptolemy/Trust        Berkeley, CA 94720-1774
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