jyapayne/Nim
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

move type operation section and remove deepcopy document (#19389)

Browse source 
ref #19173; because deepcopy is not fit for ORC/ARC which was used for spawn and spawn will be removed from compiler
This commit is contained in:
flywind 2022-01-15 18:25:09 +08:00 • committed by GitHub
commit 342b74ef70
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
2 changed files with 26 additions and 40 deletions
Download patch file Download diff file Expand all files Collapse all files

12
doc/manual.rst
View file

@ -3902,6 +3902,18 @@ the operator is in scope (including if it is private).
Type bound operators are: Type bound operators are:
`=destroy`, `=copy`, `=sink`, `=trace`, `=deepcopy`. `=destroy`, `=copy`, `=sink`, `=trace`, `=deepcopy`.
These operations can be *overridden* instead of *overloaded*. This means that
the implementation is automatically lifted to structured types. For instance,
if the type `T` has an overridden assignment operator `=`, this operator is
also used for assignments of the type `seq[T]`.
Since these operations are bound to a type, they have to be bound to a
nominal type for reasons of simplicity of implementation; this means an
overridden `deepCopy` for `ref T` is really bound to `T` and not to `ref T`.
This also means that one cannot override `deepCopy` for both `ptr T` and
`ref T` at the same time, instead a distinct or object helper type has to be
used for one pointer type.
For more details on some of those procs, see For more details on some of those procs, see
`Lifetime-tracking hooks <destructors.html#lifetimeminustracking-hooks>`_. `Lifetime-tracking hooks <destructors.html#lifetimeminustracking-hooks>`_.

52
doc/manual_experimental.rst
View file

@ -1192,51 +1192,25 @@ object inheritance syntax involving the `of` keyword:
the `vtptr` magic produced types bound to `ptr` types. the `vtptr` magic produced types bound to `ptr` types.
Type bound operations ..
===================== deepCopy
--------
`=deepCopy` is a builtin that is invoked whenever data is passed to
a `spawn`'ed proc to ensure memory safety. The programmer can override its
behaviour for a specific `ref` or `ptr` type `T`. (Later versions of the
language may weaken this restriction.)
There are 4 operations that are bound to a type: The signature has to be:
1. Assignment .. code-block:: nim
2. Moves
3. Destruction
4. Deep copying for communication between threads
These operations can be *overridden* instead of *overloaded*. This means that
the implementation is automatically lifted to structured types. For instance,
if the type `T` has an overridden assignment operator `=`, this operator is
also used for assignments of the type `seq[T]`.
Since these operations are bound to a type, they have to be bound to a
nominal type for reasons of simplicity of implementation; this means an
overridden `deepCopy` for `ref T` is really bound to `T` and not to `ref T`.
This also means that one cannot override `deepCopy` for both `ptr T` and
`ref T` at the same time, instead a distinct or object helper type has to be
used for one pointer type.
Assignments, moves and destruction are specified in
the `destructors <destructors.html>`_ document.
deepCopy
--------
`=deepCopy` is a builtin that is invoked whenever data is passed to
a `spawn`'ed proc to ensure memory safety. The programmer can override its
behaviour for a specific `ref` or `ptr` type `T`. (Later versions of the
language may weaken this restriction.)
The signature has to be:
.. code-block:: nim
proc `=deepCopy`(x: T): T proc `=deepCopy`(x: T): T
This mechanism will be used by most data structures that support shared memory, This mechanism will be used by most data structures that support shared memory,
like channels, to implement thread safe automatic memory management. like channels, to implement thread safe automatic memory management.
The builtin `deepCopy` can even clone closures and their environments. See The builtin `deepCopy` can even clone closures and their environments. See
the documentation of `spawn <#parallel-amp-spawn-spawn-statement>`_ for details. the documentation of `spawn <#parallel-amp-spawn-spawn-statement>`_ for details.
Dynamic arguments for bindSym Dynamic arguments for bindSym