withVisible: Return both a value and its visibility
Description
This function evaluates an expression, returning it in a two element list
containing its value and a flag showing whether it would automatically print.
Usage
withVisible(x)
Arguments
x
An expression to be evaluated.
Value
value
The value of x after evaluation.
visible
logical; whether the value would auto-print.
Details
The argument is evaluated in the caller's context.
x <- 1
withVisible(x <- 1)
x
withVisible(x)
# Wrap the call in evalq() for special handlingdf <- data.frame(a = 1:5, b = 1:5)
evalq(withVisible(a + b), envir = df)