R: Makevars variables

with_makevars {withr} | R Documentation

## Makevars variables

### Description

Temporarily change contents of an existing `Makevars` file.

### Usage

    with_makevars(new, code, path = file.path("~", ".R", "Makevars"),
      assignment = c("=", ":=", "?=", "+="))

### Arguments

`new` | `[named character]` New variables and their values
`code` | `[any]` Code to execute in the temporary environment
`path` | `[character(1)]` location of existing `Makevars` file to modify.
`assignment` | `[character(1)]` assignment type to use.

### Details

If no `Makevars` file exists or the fields in `new` do not exist in the existing `Makevars` file then the fields are added to the new file. Existing fields which are not included in `new` are appended unchanged. Fields which exist in `Makevars` and in `new` are modified to use the value in `new`.

### Value

`[any]`
The results of the evaluation of the `code` argument.

### See Also

`withr` for examples

[Package withr version 2.1.2 Index]