-----------------------------------------
# rlang 0.4.4
* Maintenance release for CRAN.
-----------------------------------------
# rlang 0.4.3
* You can now use glue syntax to unquote on the LHS of `:=`. This
syntax is automatically available in all functions taking dots with
`list2()` and `enquos()`, and thus most of the tidyverse. Note that
if you use the glue syntax in an R package, you need to import glue.
A single pair of braces triggers normal glue interpolation:
```r
df <- data.frame(x = 1:3)
suffix <- "foo"
df %>% dplyr::mutate("var_{suffix}" := x * 2)
#> x var_foo
#> 1 1 2
#> 2 2 4
#> 3 3 6
```
Using a pair of double braces is for labelling a function argument.
Technically, this is shortcut for `"{as_label(enquo(arg))}"`. The
syntax is similar to the curly-curly syntax for interpolating
function arguments:
```r
my_wrapper <- function(data, var, suffix = "foo") {
data %>% dplyr::mutate("{{ var }}_{suffix}" := {{ var }} * 2)
}
df %>% my_wrapper(x)
#> x x_foo
#> 1 1 2
#> 2 2 4
#> 3 3 6
df %>% my_wrapper(sqrt(x))
#> x sqrt(x)_foo
#> 1 1 2.000000
#> 2 2 2.828427
#> 3 3 3.464102
```
* Fixed a bug in magrittr backtraces that caused duplicate calls to
appear in the trace.
* Fixed a bug in magrittr backtraces that caused wrong call indices.
* Empty backtraces are no longer shown when `rlang_backtrace_on_error`
is set.
* The tidy eval `.env` pronoun is now exported for documentation
purposes.
* `warn()` and `abort()` now check that either `class` or `message`
was supplied. `inform()` allows sending empty message as it is
occasionally useful for building user output incrementally.
* `flatten()` fails with a proper error when input can't be flattened (#868, #885).
* `inform()` now consistently appends a final newline to the message
(#880).
* `cnd_body.default()` is now properly registered.
* `cnd_signal()` now uses the same approach as `abort()` to save
unhandled errors to `last_error()`.
* Parsable constants like `NaN` and `NA_integer_` are now deparsed by
`expr_deparse()` in their parsable form (#890).
* Infix operators now stick to their LHS when deparsed by
`expr_deparse()` (#890).
-----------------------------------------
# rlang 0.4.2
* New `cnd_header()`, `cnd_body()` and `cnd_footer()` generics. These
are automatically called by `conditionMessage.rlang_error()`, the
default method for all rlang errors.
Concretely, this is a way of breaking up lazy generation of error
messages with `conditionMessage()` into three independent
parts. This provides a lot of flexibility for hierarchies of error
classes, for instance you could inherit the body of an error message
from a parent class while overriding the header and footer.
* The reminder to call `last_error()` is now less confusing thanks to
a suggestion by @markhwhiteii.
* The functions prefixed in `scoped_` have been renamed to use the
more conventional `local_` prefix. For instance, `scoped_bindings()`
is now `local_bindings()`. The `scoped_` functions will be
deprecated in the next significant version of rlang (0.5.0).
* The `.subclass` argument of `abort()`, `warn()` and `inform()` has
been renamed to `class`. This is for consistency with our
conventions for class constructors documented in
https://adv-r.hadley.nz/s3.html#s3-subclassing.
* `inform()` now prints messages to the standard output by default in
interactive sessions. This makes them appear more like normal output
in IDEs such as RStudio. In non-interactive sessions, messages are
still printed to standard error to make it easy to redirect messages
when running R scripts (#852).
* Fixed an error in `trace_back()` when the call stack contains a
quosured symbol.
* Backtrace is now displayed in full when an error occurs in
non-interactive sessions. Previously the backtraces of parent errors
were left out.
-----------------------------------------
# rlang 0.4.1
* New experimental framework for creating bulleted error messages. See
`?cnd_message` for the motivation and an overwiew of the tools we
have created to support this approach. In particular, `abort()` now
takes character vectors to assemble a bullet list. Elements named
`x` are prefixed with a red cross, elements named `i` are prefixed
with a blue info symbol, and unnamed elements are prefixed with a
bullet.
* Capture of backtrace in the context of rethrowing an error from an
exiting handler has been improved. The `tryCatch()` context no
longer leaks in the high-level backtrace.
* Printing an error no longer recommends calling `last_trace()`,
unless called from `last_error()`.
* `env_clone()` no longer recreates active bindings and is now just an
alias for `env2list(as.list(env))`. Unlike `as.list()` which returns
the active binding function on R < 4.0, the value of active bindings
is consistently used in all versions.
* The display of rlang errors derived from parent errors has been
improved. The simplified backtrace (as printed by
`rlang::last_error()`) no longer includes the parent errors. On the
other hand, the full backtrace (as printed by `rlang::last_trace()`)
now includes the backtraces of the parent errors.
* `cnd_signal()` has improved support for rlang errors created with
`error_cnd()`. It now records a backtrace if there isn't one
already, and saves the error so it can be inspected with
`rlang::last_error()`.
* rlang errors are no longer formatted and saved through
`conditionMessage()`. This makes it easier to use a
`conditionMessage()` method in subclasses created with `abort()`,
which is useful to delay expensive generation of error messages
until display time.
* `abort()` can now be called without error message. This is useful
when `conditionMessage()` is used to generate the message at
print-time.
* Fixed an infinite loop in `eval_tidy()`. It occurred when evaluating
a quosure that inherits from the mask itself.
* `env_bind()`'s performance has been significantly improved by fixing a bug
that caused values to be repeatedly looked up by name.
* `cnd_muffle()` now checks that a restart exists before invoking
it. The restart might not exist if the condition is signalled with a
different function (such as `stop(warning_cnd)`).
* `trace_length()` returns the number of frames in a backtrace.
* Added internal utility `cnd_entrace()` to add a backtrace to a
condition.
* `rlang::last_error()` backtraces are no longer displayed in red.
* `x %|% y` now also works when `y` is of same length as `x` (@rcannood, #806).
* Empty named lists are now deparsed more explicitly as
`"<named list>"`.
* Fixed `chr()` bug causing it to return invisibly.
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