nwsFetchTry-methods: Fetch a Value from a NetWorkSpace (Non-Blocking Version)
In nws: R functions for NetWorkSpaces and Sleigh

Description Usage Arguments Details See Also Examples

Attempt to fetch a value associated with a variable from the shared netWorkSpace; a non-blocking version of nwsFetch.

1 2	## S4 method for signature 'netWorkSpace' nwsFetchTry(.Object, xName, defaultVal=NULL)

`.Object`	a netWorkSpace class object
`xName`	name of the variable to be fetched
`defaultVal`	value to return, if xName is not found in the netWorkSpace

Look in the shared netWorkSpace for a value bound to xName. If found, remove a value associated with xName from the shared netWorkSpace. This operation is atomic. If there are multiple nwsFetch or nwsFetchTry requests for a given xName, any given value from the set of values associated with xName will be returned to just one requester.

If variable is not found, return immediately rather than block on the operation (as in the case of nwsFetch). If variable is not found, the value of argument defaultVal is returned. By default, defaultVal is NULL.

nwsDeclare, nwsFetch

## Not run: 
ws <- netWorkSpace('nws example')
# If variable 'x' is not found in the shared netWorkSpace,
# return default value, NULL.
nwsFetchTry(ws, 'x')
# If variable 'x' is not found in the shared netWorkSpace, 
# return 10.
nwsFetchTry(ws, 'x', 10)

## End(Not run)