NEWS.md
In lionel-/flowery: 'Coroutines' for R

coro (development version)

coro 1.0.4

Internal fix for R-devel.

coro 1.0.3

coro::as_iterator() method added for reticulate Python objects, enabling usage like: coro::loop(for (elem in my_py_object) ...) (#37, @t-kalinowski).

coro 1.0.2

The exhaustion sentinel is now as.symbol(".__exhausted__.") instead of as.symbol("exhausted") to reduce the risk of collisions. It is also recommended to never store the exhaustion sentinel in an environment or list, and instead use it as a temporary value to further reduce the risk of collisions (#35).
Fixed a leak that occurred via JIT caching (#36).

coro 1.0.1

collect() now preserves lists and data frames (#32).

coro 1.0.0

This is the first public version of coro.

Python iterators created with the reticulate package can now be composed with coro generators. They can also be used with loop() and collect().
iterate() has been renamed to loop() to avoid name clash and semantic conflict with reticulate::iterate().
collect() calls as_iterator() on its input.
as_iterator() is now a generic function (#28).
Generators and async functions now support on.exit() expressions. They also support exit expressions installed with functions like withr::local_options(). This requires R >= 3.5.
Generator arguments are forced on reentry in the approriate context (e.g. in the tryCatch() context if generator was yielded from a tryCatch()). This makes it possible to clean up cancelled generators (by jumping from the generator with a restart) or propagate errors in async functions.
Generators and async functions now support yielding within tryCatch() expressions.
Generators and async functions are now disabled when an unexpected exit occurs (error, interrupt, restart invokation, debugger exit, etc.). Reentering the generator is an error.
Generators and async functions now support stepping with browser(). Set options(coro_debug = TRUE) for browsing all functions created with coro. Use coro_debug() for browsing specific functions.
generator() now accepts functions of one argument. The first time a generator is called the argument is defined in the suspendable function. On subsequent invokations, the argument is returned from yield().
generator() now creates generator factories. It takes a function template and returns a function that creates generator functions from this template. This is consistent with languages like Javascript and Python.
The async() function operator creates functions for cooperative concurrency using the later and promises framework.

async_generator() creates iterable functions that are also awaitable.

The iterator abstraction has been removed from coro. It is replaced with the following protocol:
An iterator is a function. You advance it and get a new value by calling it.
An iterator signals exhaustion by returning exhausted() (or equivalently, the quote(exhausted) symbol).
Exhausted generators no longer throw when called again. Instead, they return the exhausted() sentinel (#6).
Fixed top-level break statements in loops (#7).