| callArg {playwith} | R Documentation |
Part of the playwith Application Programming Interface.
callArg(playState, arg, eval = TRUE, data = NULL) callArg(playState, arg) <- value mainCall(playState) mainCall(playState) <- value updateMainCall(playState)
playState |
a playState object representing the plot, window and device. |
arg |
the argument name or number in the main plot call.
This can also be a language object
(e.g. quote(scales$log)).
Argument numbers start from 1 (so 0 refers to the main function name).
This is evaluated in the calling environment, so can
refer to local variables (e.g. data[[myname]]).
|
eval |
whether to evaluate the argument before returning it. Otherwise, just return the argument as it appears in the call. |
data |
a list or environment in which to evaluate the argument. Typically this will be the "data" argument to lattice or qplot functions. |
value |
the value to assign. |
These functions get and set argument values in the playState plot call.
As convenience functions for setting arguments in playState$call,
the callArg function helps by:
playState$env).
exact=TRUE (see [[).
returns the value of the specified argument, possibly
evaluated in a local environment (playState$env).
Felix Andrews felix@nfrac.org
if (interactive()) {
library(lattice)
playwith(xyplot(1:10 ~ 1:10))
playState <- playDevCur()
callArg(playState, "pch") ## NULL
callArg(playState, "pch") <- "$"
callArg(playState, "pch") ## "$"
playReplot(playState)
## referring to local variables
tmp <- "x"
callArg(playState, quote(scales[[tmp]]$cex)) <- 2
playReplot(playState)
}