R: Return both a value and its visibility

withVisible {base} | 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.

This is a primitive function.

### 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)

[Package base version 2.15.1 Index]