update subtree entt Merge commit '90ce4bda4e1dc23508bbd6b6923156cd5a370c18'

external/entt/entt/docs/md/process.md

@@ -15,18 +15,17 @@
 
 # Introduction
 
-Sometimes processes are a useful tool to work around the strict definition of a
-system and introduce logic in a different way, usually without resorting to the
-introduction of other components.
-
-`EnTT` offers a minimal support to this paradigm by introducing a few classes
-that users can use to define and execute cooperative processes.
+Processes are a useful tool to work around the strict definition of a system and
+introduce logic in a different way, usually without resorting to other component
+types.<br/>
+`EnTT` offers minimal support to this paradigm by introducing a few classes used
+to define and execute cooperative processes.
 
 # The process
 
-A typical process must inherit from the `process` class template that stays true
-to the CRTP idiom. Moreover, derived classes must specify what's the intended
-type for elapsed times.
+A typical task inherits from the `process` class template that stays true to the
+CRTP idiom. Moreover, derived classes specify what the intended type for elapsed
+times is.
 
 A process should expose publicly the following member functions whether needed
 (note that it isn't required to define a function unless the derived class wants
@@ -34,39 +33,38 @@ to _override_ the default behavior):
 
 * `void update(Delta, void *);`
 
-  It's invoked once per tick until a process is explicitly aborted or it
-  terminates either with or without errors. Even though it's not mandatory to
-  declare this member function, as a rule of thumb each process should at
-  least define it to work properly. The `void *` parameter is an opaque pointer
-  to user data (if any) forwarded directly to the process during an update.
+  This is invoked once per tick until a process is explicitly aborted or ends
+  either with or without errors. Even though it's not mandatory to declare this
+  member function, as a rule of thumb each process should at least define it to
+  work _properly_. The `void *` parameter is an opaque pointer to user data (if
+  any) forwarded directly to the process during an update.
 
 * `void init();`
 
-  It's invoked when the process joins the running queue of a scheduler. This
-  happens as soon as it's attached to the scheduler if the process is a top
-  level one, otherwise when it replaces its parent if the process is a
-  continuation.
+  This is invoked when the process joins the running queue of a scheduler. It
+  happens usually as soon as the process is attached to the scheduler if it's a
+  top level one, otherwise when it replaces its parent if it's a _continuation_.
 
 * `void succeeded();`
 
-  It's invoked in case of success, immediately after an update and during the
+  This is invoked in case of success, immediately after an update and during the
   same tick.
 
 * `void failed();`
 
-  It's invoked in case of errors, immediately after an update and during the
+  This is invoked in case of errors, immediately after an update and during the
   same tick.
 
 * `void aborted();`
 
-  It's invoked only if a process is explicitly aborted. There is no guarantee
-  that it executes in the same tick, this depends solely on whether the
-  process is aborted immediately or not.
+  This is invoked only if a process is explicitly aborted. There is no guarantee
+  that it executes in the same tick, it depends solely on whether the process is
+  aborted immediately or not.
 
 Derived classes can also change the internal state of a process by invoking
-`succeed` and `fail`, as well as `pause` and `unpause` the process itself. All
-these are protected member functions made available to be able to manage the
-life cycle of a process from a derived class.
+`succeed` and `fail`, as well as `pause` and `unpause` the process itself.<br/>
+All these are protected member functions made available to manage the life cycle
+of a process from a derived class.
 
 Here is a minimal example for the sake of curiosity:
 
@@ -95,14 +93,14 @@ private:
 
 ## Adaptor
 
-Lambdas and functors can't be used directly with a scheduler for they are not
+Lambdas and functors can't be used directly with a scheduler because they aren't
 properly defined processes with managed life cycles.<br/>
 This class helps in filling the gap and turning lambdas and functors into
 full-featured processes usable by a scheduler.
 
 The function call operator has a signature similar to the one of the `update`
-function of a process but for the fact that it receives two extra arguments to
-call whenever a process is terminated with success or with an error:
+function of a process but for the fact that it receives two extra callbacks to
+invoke whenever a process terminates with success or with an error:
 
 ```cpp
 void(Delta delta, void *data, auto succeed, auto fail);
@@ -127,9 +125,9 @@ A cooperative scheduler runs different processes and helps managing their life
 cycles.
 
 Each process is invoked once per tick. If it terminates, it's removed
-automatically from the scheduler and it's never invoked again. Otherwise it's
+automatically from the scheduler and it's never invoked again. Otherwise, it's
 a good candidate to run one more time the next tick.<br/>
-A process can also have a child. In this case, the parent process is replaced
+A process can also have a _child_. In this case, the parent process is replaced
 with its child when it terminates and only if it returns with success. In case
 of errors, both the parent process and its child are discarded. This way, it's
 easy to create chain of processes to run sequentially.
@@ -138,18 +136,25 @@ Using a scheduler is straightforward. To create it, users must provide only the
 type for the elapsed times and no arguments at all:
 
 ```cpp
-entt::scheduler<std::uint32_t> scheduler;
+entt::basic_scheduler<std::uint64_t> scheduler;
 ```
 
-It has member functions to query its internal data structures, like `empty` or
-`size`, as well as a `clear` utility to reset it to a clean state:
+Otherwise, the `scheduler` alias is also available for the most common cases. It
+uses `std::uint32_t` as a default type:
+
+```cpp
+entt::scheduler scheduler;
+```
+
+The class has member functions to query its internal data structures, like
+`empty` or `size`, as well as a `clear` utility to reset it to a clean state:
 
 ```cpp
 // checks if there are processes still running
 const auto empty = scheduler.empty();
 
 // gets the number of processes still running
-entt::scheduler<std::uint32_t>::size_type size = scheduler.size();
+entt::scheduler::size_type size = scheduler.size();
 
 // resets the scheduler to its initial state and discards all the processes
 scheduler.clear();
@@ -173,7 +178,7 @@ To attach a process to a scheduler there are mainly two ways:
   ```
 
 In both cases, the return value is an opaque object that offers a `then` member
-function to use to create chains of processes to run sequentially.<br/>
+function used to create chains of processes to run sequentially.<br/>
 As a minimal example of use:
 
 ```cpp
@@ -201,7 +206,7 @@ scheduler.update(delta, &data);
 ```
 
 In addition to these functions, the scheduler offers an `abort` member function
-that can be used to discard all the running processes at once:
+that is used to discard all the running processes at once:
 
 ```cpp
 // aborts all the processes abruptly ...