Evaluate expr with bquote .() substitution.
Including .(-x) promoting x's value from character to a name,
which is called "quote negation" (hence the minus-sign).
evalb(expr, where = parent.frame())expression to evaluate.
environment to work in.
evaluated substituted expression.
if(requireNamespace('graphics', quietly = TRUE)) {
angle = 1:10
variable <- as.name("angle")
fn_name <- 'sin'
evalb( plot(x = .(variable), y = .(-fn_name)(.(variable))) )
}