| nwsVariable {nws} | R Documentation |
nwsVariable creates a variable in an R workspace that mirrors
a variable in a netWorkSpace. This allows standard R operations
(get, assign) to be used to share data between R programs running on
different machines.
## S4 method for signature 'netWorkSpace':
nwsVariable(.Object, xName, mode=c('fifo','lifo','multi','single'),env=parent.frame(),force=FALSE,quietly=FALSE)
.Object |
a netWorkSpace class object. |
xName |
name of variable to be declared. |
mode |
mode of the variable, see details. |
env |
environment in which to define active binding. |
force |
logical; if TRUE, an existing binding will be overwritten. |
quietly |
logical; if TRUE, no warnings are issued. |
nwsVariable is built on top of the R makeActiveBinding
function. It is experimental, but we have found that it is very
useful for introducing people to the concept of netWorkSpace
variables. It's not clear that this API is ever preferable to
nwsStore, nwsFetch, nwsFind for real programs,
however.
The mode of the variable controls what happens when a variable
is accessed. If the mode is 'single', then all accesses use
the nwsFind operation. If the mode is 'fifo',
'lifo', or 'multi', then all accesses use the
nwsFetch operation.
Assigning a value to an nwsVariable always uses the
nwsStore operation.
## Not run:
# create a netWorkSpace
ws = netWorkSpace('nws example')
# create a variable in the local R workspace that is linked to
# a netWorkSpace variable
nwsVariable(ws, 'x', 'single')
x <- 0
x <- 999 # overwrites the 0
x <- 3.14159 # overwrites the 999
x # returns 3.14159
x # returns 3.14159
x # returns 3.14159
# create a 'fifo' mode variable
nwsVariable(ws, 'message', 'fifo')
message <- 1
message <- 2
message <- 3
message # returns 1
message # returns 2
message # returns 3
## End(Not run)