withVisible              package:utils              R Documentation

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. 

Details:

     The argument is evaluated in the caller's context.

Value:

  value : The value of 'x' after evaluation.

visible : logical; whether the value would auto-print.

See Also:

     'invisible', 'eval'

Examples:

     x <- 1
     withVisible(x <- 1)
     x
     withVisible(x)

     # Wrap the call in evalq() for special handling

     df <- data.frame(a=1:5, b=1:5)
     evalq(withVisible(a + b), envir=df)

