On Jan 30, 10:49 am, wolffiex <[email protected]> wrote:
> Hi list,
> I've been a happy Rhino user for a long time, but I'm looking at
> getting deeper into it, in order to add this feature to my app: Given
> the string source of a function, I'd like to get a list of all the
> closed-over variables within it. So, for instance:
>
> myNewApi.getFreeVariables("function(a){ var b = 2; return a+b+c
> +d; }");
>
> would return the list of "c" and "d".
>
> I've poked around the source for 1.7R2 but I didn't see any javadoc
> that would suggest how to do this. Even a pointer in the right
> direction would be very helpful.
>
> Thanks!
> A
Ok solved. I've pasted example code below. Now a follow up question:
is Parser.parse thread safe, or do I need a new instance for each
thread?
public ScriptableObject getFreeVariables(String f){
ScriptOrFnNode firstFunction = null;
try{
ScriptOrFnNode node = parser.parse(f, "free variable
getter", 0);
firstFunction = node.getFunctionNode(0);
}catch (Exception e){
logger.error("Can't find function in " + f);
}
ScriptableObject jsSet = makeJSObject();
if (firstFunction != null){
Set<String> varNames = new HashSet<String>();
addVarNames(firstFunction, varNames);
final Map<String,? extends Object> symbolTable =
firstFunction.getSymbolTable();
if (symbolTable != null)
varNames.removeAll(symbolTable.keySet());
for (String varName : varNames){
jsSet.put(varName, jsSet, true);
}
}
return jsSet;
}
private void addVarNames(final Node fn, final Set<String> vars) {
if (fn.getType() == Token.NAME) {
vars.add(fn.getString());
}
if (fn.hasChildren()){
Node p = fn.getFirstChild();
do{
addVarNames(p, vars);
p = p.getNext();
}while(p!=null);
}
}
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