Description Usage Arguments Details Value Author(s) See Also Examples
Part of the playwith Application Programming Interface.
1 2 3 4 5 6 7 |
playState |
a |
arg |
the argument name or number in the main plot call.
This can also be a language object
(e.g. |
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$call
,
the callArg
function helps by:
referring to the main call that accepts plot arguments, which is not necessarily the top-level call.
automatically evaluating variables that have been stored in a local environment
(playState$env
).
converting lists to language objects as needed.
enforcing exact matching of argument names exact=TRUE
(see [[
).
returns the value of the specified argument, possibly
evaluated in a local environment (playState$env
).
Felix Andrews felix@nfrac.org
playwith.API
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | if (interactive()) {
library(lattice)
playwith(xyplot(1:10 ~ 1:10))
playState <- playDevCur()
callArg(playState, "pch") ## NULL
callArg(playState, "pch") <- "$"
callArg(playState, "pch") ## "$"
playReplot(playState)
## referring to local variables
tmp <- "x"
callArg(playState, quote(scales[[tmp]]$cex)) <- 2
playReplot(playState)
}
|
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