[R] Passing expression as argument to do.call

[Sebastien Bihorel]

Dear R-users,

I would like to know how expressions could be passed as arguments to 
do.call functions. As illustrated in the short example below, 
concatenating lists objects and an expression creates an expression 
object, which is not an acceptable argument for do.call. Is there a way 
to avoid that?

Thanks you

Sebastien


foo <- list(x=1:10, y=1:10)
mylist <- list(pch=6, col=2)
title <- "1 microgram"
title2 <- expression ("1 " mu "g")

do.call(plot, c(foo, mylist, main=title))

class(c(foo, mylist, main=title2))

do.call(plot, c(foo, mylist, main=title2))