Webcore Child return parameters

Hi There,

hoping someone can help with this.. I've looked everywhere for documentation and cant find any.

Issue: I want to return a parameter from a Child Piston and I dont know how.

so I have : Execute Piston "Child Piston" with arguments (to-child, from-child);

My child piston uses "to-child' via the args but how do i get "from-child" to be be sent and used by the Parent (calling) Piston ?

Thanks in advance

I don't know that you can return parameters on a call. You may need to use global variables, or have the piston that receives the call to make a call back.


  • If you need a larger application, you can use multiple pistons, and have a main piston call the sub-pistons. Again, leave the wait = true on when performing "execute piston"
    • do note:
      • to pass data to a piston, you can use arguments on the piston call, or global variables.
      • to get data returned from a piston execution, global variables are often the best choice.
      • note that a piston can subscribe to a global variable change. (globalvariable changes). This design paradigm can make it easy to not worry about the loading comments below.
        • global variables are "loaded" when a piston starts, and saved when a piston exits, so if:
          • Piston A calls piston B, and B modifies a global variable, piston A will not see the change until the next time piston A executes.
          • Piston A modifies a variable and calls piston B, since A has not exited yet, the change to the global variable is likely not to be seen by B until B runs again after A has exited (and saved changes)


Thanks extremely helpful and saved me endless hours of frustration....

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