This is a companion to `base::append()`

to help merging two lists
or atomic vectors. `prepend()`

is a clearer semantic signal than
`c()`

that a vector is to be merged at the beginning of another,
especially in a pipe chain.

prepend(x, values, before = 1)

## Arguments

x |
the vector to be modified. |

values |
to be included in the modified vector. |

before |
a subscript, before which the values are to be appended. |

## Value

A merged vector.

## Life cycle

`prepend()`

is experimental, expect API changes. We are still
figuring out what vector tools belong in rlang.

## Examples

x <- as.list(1:3)
append(x, "a")

#> [[1]]
#> [1] 1
#>
#> [[2]]
#> [1] 2
#>
#> [[3]]
#> [1] 3
#>
#> [[4]]
#> [1] "a"
#>

prepend(x, "a")

#> [[1]]
#> [1] "a"
#>
#> [[2]]
#> [1] 1
#>
#> [[3]]
#> [1] 2
#>
#> [[4]]
#> [1] 3
#>

prepend(x, list("a", "b"), before = 3)

#> [[1]]
#> [1] 1
#>
#> [[2]]
#> [1] 2
#>
#> [[3]]
#> [1] "a"
#>
#> [[4]]
#> [1] "b"
#>
#> [[5]]
#> [1] 3
#>