Commit Graph
50 Commits
Author SHA1 Message Date
josh11bandJosh L efb78c593c Update design for proposal #6395: Type completeness in extend (#7315)
Assisted-by: Gemini via Antigravity

Co-authored-by: Josh L <josh11b@users.noreply.github.com>
2026-06-08 21:27:48 +00:00
Chandler CarruthandRichard Smith 94d2c1c6d4 Make proposal filenames use 6 digits and include the title (#7245)
We've talked about adding the title to the filename several times over
the years and it seems really valuable. This requires us to compute a
"slug" for the title spelling that can be part of the filename.

Beyond that, we crossed 7000 recently, and so it seems likely that we
will need to add digits sooner rather than later here, so this goes
ahead and moves us to 6 digits so we don't have to adjust again for a
reasonable length of time.

To implement this and ensure we can sustain it going forward this adds a
tool to our pre-commit that validates (and corrects if needed) the
filename.

In order to update everything and keep links working, there are a _lot_
of changes, but the most interesting for direct review are in
`proposals/scripts`.

Assisted-by: Antigravity with Gemini

---------

Co-authored-by: Richard Smith <richard@metafoo.co.uk>
2026-05-29 00:55:04 +00:00
Chandler Carruth 2047e08635 Update examples throughout the design for p7016 (#7200)
Also updates a few spots with some subtle aspects changed in
`lambdas.md` and `namespace_cleanliness.md`.

Assisted-by: Antigravity with Gemini
2026-05-13 18:42:55 +00:00
10b2b71847 Updating self syntax and adding static member variables (#7016)
Update the syntax for class (and interface/`impl`) methods to move
`self` into
the parameter parentheses `()` and make the type in its binding optional
(defaulting to `Self`). Introduce the `static` keyword for non-instance
member
variables to indicate static storage. Reflects the decision in leads
issue
[#6931](https://github.com/carbon-language/carbon-lang/issues/6931).

Updates the directly relevant design, but leaves a systematic update of
examples
to a future PR.

Assisted-by: Antigravity with Gemini

---------

Co-authored-by: Geoff Romer <gromer@google.com>
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
2026-05-13 01:30:44 +00:00
2d5e5e9692 Expression form basics (#5545)
This proposal introduces the concept of a _form_, which is a
generalization of
"type" that encompasses all of the information about an expression
that's
visible to the type system, including type and expression category.
Forms can be
composed into _tuple forms_ and _struct forms_, which lets us track the
categories of individual tuple and struct literal elements.

The proposal PR also adds `ref` bindings to the pattern matching
documentation,
but that is not part of the proposal itself; it's just bringing the
documentation
up to date with proposal
[#5434](https://github.com/carbon-language/carbon-lang/pull/5434).

---------

Co-authored-by: josh11b <15258583+josh11b@users.noreply.github.com>
Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Co-authored-by: Carbon Infra Bot <carbon-external-infra@google.com>
2026-02-10 17:44:50 +00:00
Calvin bd4d5805dd Replace addr with ref in design docs (#6141)
Updates the documentation under `docs/design/` to use `ref` instead of
`addr` after their removal in #5434. Care was taken to manually clean up
edge cases and, in a couple cases, surrounding text (see
3d72c49bb75c0f40ca7e8114b6a1369b941e1697). After this change, there are
no matches for `addr(?!ess)` in `docs/design/`.

Closes #6032
2025-10-06 18:44:24 +00:00
Geoff RomerandRichard Smith c713279a3d Keep design documents current (#5606)
Require language design proposals to either update the design documents
to
reflect the proposed changes, or add "TODO" comments to mark where those
changes
will be needed, with links back to the proposal. This is intended to
ensure that
the design documentation accurately informs readers about the current
language
design, without excessively burdening the proposal process.

---------

Co-authored-by: Richard Smith <richard@metafoo.co.uk>
2025-10-01 20:12:05 +00:00
Elliott KaltandRichard Smith f4bd6e42f9 Replace impl fn with override fn (#6008)
This proposal renames the syntax used to mark an overriding definition
of a virtual method from `impl fn` to `override fn` to avoid ambiguity:
besides indicating an overriding virtual function, it can be parsed as
an "impl" declaration when the construct following "impl" begins with a
lambda introduced by "fn".

Closes #5711

---------

Co-authored-by: Richard Smith <richard@metafoo.co.uk>
2025-09-12 23:27:02 +00:00
josh11bandJosh L e52b51e66a Forbid virtual methods with compile-time parameters in the design (#5365)
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
2025-04-26 03:30:25 +00:00
Jon Ross-PerkinsandChandler Carruth 10a87c045a Destructor syntax (#5017)
Fix destructor syntax ambiguity by switching to `fn destroy` mirroring
standard function syntax. This is a purely syntactic change, maintaining
destructor semantics.

This comes from leads question #4999

---------

Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
2025-03-05 16:38:44 +00:00
Jon Ross-Perkins d843cc53fb Small rephrasing of 'partial' interaction with final classes (#5000)
I believe this reflects the intent, but the phrasing of "even if
`MyBaseClass` is not" implies that `MyBaseClass` _can_ be final in
`partial MyBaseClass`. Also, make clear it's allowed on `abstract`
classes, not only `base` (this seems explicitly intended from the
`MyAbstractClass` example around line 1482).
2025-02-21 21:52:45 +00:00
Dana Jansens 88283bfc56 Make open question on class variables more explicit (#4988) 2025-02-20 18:56:10 +00:00
Geoff Romerandjosh11b 09b06b4234 Document grammar of field and associated constant decls (#4980)
Co-authored-by: josh11b <15258583+josh11b@users.noreply.github.com>
2025-02-20 01:28:01 +00:00
josh11bandJosh L 4994e13068 Document that extend base must appear early in a class definition (#4401)
Note: some of this is from the principle of information accumulation,
and some is from [proposal
#2760](https://github.com/carbon-language/carbon-lang/blob/trunk/proposals/p2760.md#class-inheritance).

Also: change terminology from "virtual override keywords" to "virtual
modifier keywords", to be consistent with our other modifier keywords.

---------

Co-authored-by: Josh L <josh11b@users.noreply.github.com>
2024-10-11 19:51:15 +00:00
josh11bandJosh L b0cde707f8 Rename "partial facet" and to "partial class type" (#4402)
See [2024-10-01 discussion on #typesystem in
Discord](https://discord.com/channels/655572317891461132/708431657849585705/1290774105498325122).

Co-authored-by: Josh L <josh11b@users.noreply.github.com>
2024-10-11 18:25:18 +00:00
Richard Smith 6bbbd4ec1f More consistent package syntax (#3927)
Change the syntax for `package` declarations from:

```carbon
[package Foo] [library "bar"] api;
[package Foo] [library "bar"] impl;
```

to

```carbon
[package Foo] [library "bar"];
impl [package Foo] [library "bar"];
```
2024-05-16 00:55:37 +00:00
Jon Ross-Perkins 0a117f6e73 Switch example code from Create to Make (#3705)
There's not explicit guidance about this, but there was an [old
discussion](https://discord.com/channels/655572317891461132/963846118964350976/998010464237785189)
that loosely settled on Make for now.
2024-02-21 16:43:52 +00:00
josh11bandChandler Carruth 58c106010c Updates to design docs to reflect accepted proposals (#3254)
Includes proposals:
- #990
- #2188
- #2138
- #2200
- #2360
- #2760
- #2964
- #3162

Also tries to use more precise language when talking about:
- implementations, to avoid confusing `impl` declaration and definitions
with the `impls` operator used in `where` clauses, an issue brought up
in #2495 and #2483;
- "binding patterns", like `x: i32`, and "bindings" like `x`.

---------

Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
2023-09-23 15:53:07 +00:00
josh11bandRichard Smith a8ca499450 Updates to generics design details, part 1 (#3231)
First step in updating `docs/design/generics/details.md`. It
incorporates changes from proposals: #989 #2138 #2173 #2200 #2360 #2964
#3162 , but there are still more changes from those proposals to be
made.

It also switches away from suggesting static-dispatch witness tables,
and creates an appendix to describe that decision.

---------

Co-authored-by: Richard Smith <richard@metafoo.co.uk>
2023-09-19 19:06:47 +00:00
587ab64d1b Update Generics terminology document (#3048)
This reflects changes from a number of approved proposals:
- #920 : concrete statements about orphan and overlap in Carbon
- #2138 : "generic" -> "checked generic", "template" -> "template
generic"
- #2188 : binding patterns are forbidden in type position
- #2360 : "type", "facet type", "facet". Note: I am not using the term
"generic type" from #2360 since that meaning conflicts with the
generally accepted meaning of "generic type" of a type with a
compile-time parameter.
- #2760 / #2770 : internal/external impl -> extending impl
- #2964 : "symbolic constant" and "template constant"

---------

Co-authored-by: Geoff Romer <gromer@google.com>
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
2023-08-02 23:22:15 +00:00
Jon Ross-Perkins 9c74c5dba4 Narrow example addr pattern to self. (#2970)
Although discussed for other situations, `self` is the only concrete
use-case of `addr`.
2023-07-06 18:30:30 +00:00
josh11b 2ae8117d62 Update design docs with syntax changes from #2760 (#2866)
This includes:

- Syntax changes from this chart:

| Before                          | After                                   |
| ------------------------------- | --------------------------------------- |
| `class D extends B { ... }`     | `class D { extend base: B; ... }`       |
| `external impl C as Sub;`       | `impl C as Sub;`                        |
| `class C { impl as Sortable; }` | `class C { extend impl as Sortable; }`  |
| `adapter A for C { ... }`       | `class A { adapt C; ... }`              |
| `adapter A extends C { ... }`   | `class A { extend adapt C; ... }`       |
| `interface I { impl as J; }`    | `interface I { require Self impls J; }` |
| `interface I { extends J; }`    | `interface I { extend J; }`             |

- Dropping the syntax for conditionally implemented internal interfaces.

This does not include:

- terminology changes from #2760 ("internal" and "external")
- changes to code, such as explorer, toolchain, language grammars, or other tooling
2023-06-16 14:22:29 -07:00
Adrien Leravat 65578bd8db Documentation: fix typo (#2742) 2023-04-05 16:17:03 -07:00
642fcd3b77 Replace keyword is with impls (#2483)
Use the keyword `impls` instead of `is` when writing a `where` constraint that a type variable needs to implement an interface or named constraint.

What was previously (provisionally) written:
```
fn Sort[T:! Container where .ElementType is Ordered](x: T*);
```
will now be written:
```
fn Sort[T:! Container where .ElementType impls Ordered](x: T*);
```

---------

Co-authored-by: Geoff Romer <gromer@google.com>
Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
2023-03-22 21:45:32 -07:00
Jon Ross-Perkinsandjosh11b e9480e7dfe Clean up a couple non-proposal docs links that had access issues. (#2565)
The toolchain link just needed a resourcekey.

The open discussion link may just not work because it was pre-go-public, so it points at a doc that we probably copied.

Co-authored-by: josh11b <josh11b@users.noreply.github.com>
2023-01-30 11:33:18 -08:00
a89aba2698 Assignment statements (#2511)
Assignment is permitted only as a complete statement, not as a subexpression.
Assignment and compound assignment syntax follow C++ in all other respects.
Pre-increment is provided. Post-increment is not. Uses of all of these operators
are translated into calls to interface members.

Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
2023-01-27 19:03:47 -08:00
Richard Smith 4daaa4866f Rename Type -> type, per #2360. (#2507)
Also make minor updates to the skeletal design in
docs/design/name_lookup.md following #2113, as there are no longer any prelude names that are made available to unqualified name lookup by default.

Add `type` to the keyword list in
docs/design/lexical_conventions/words.md, following #2360.
2023-01-04 14:22:30 -08:00
josh11b 9c8fd6864e Implement rename me -> self (#2444)
Implements change proposed in #1382

Replaces #1624
2022-12-06 20:17:00 -08:00
Jon Ross-PerkinsandRichard Smith 14cc716ddc Allow unqualified name lookup for class members (#2287)
Allow unqualified name lookup in multiple situations:

-   For classes and interfaces, whether inside the class scope or within an
    out-of-line function definition.
-   For namespaces, when the namespace is used in a declaration.

Co-authored-by: Richard Smith <richard@metafoo.co.uk>
2022-11-09 14:34:30 -08:00
Jon Ross-Perkins f1e36a50ca C/C++ -> C and C++ (#2340)
As requested at https://github.com/carbon-language/carbon-lang/pull/2332#discussion_r1002257672, "Very minor, but "C/C++" irritates some people in the C++ community so we may as well avoid it here."
2022-10-25 12:06:24 -07:00
Jon Ross-Perkins bd3e2bb24a Add alternatives considered to classes (#2332)
Extracting from #2287
2022-10-24 09:39:01 -07:00
Adrien Leravat 8e8e8ced60 docs: fix code sample typo (#2254)
Fix small typo in classes documentation
Added to a decicated PR to keep things orderly
2022-10-04 08:57:10 -07:00
josh11b e4595deb4b Clarify rules around Self and .Self (#2107)
A number of smaller changes grouped together in one proposal:

-   Make `Self` a keyword.
-   Clarify that `Self` refers to the current type in a base class and in impl declarations.
-   Clarify when `.Self` is legal, and what type it has.
-   Also specify that `where` is not an associative operator.
2022-09-08 13:04:58 -07:00
josh11b 4192ee42a6 Misc small fixes (#2123) 2022-08-30 08:25:24 -07:00
Richard Smith e26bc32343 Change remaining uses of Bool to bool, following #750. (#1901)
The most significant change here is that explorer now uses the chosen spelling
rather than the old `Bool` spelling. Also update a few documentation examples
and some skeletal design docs to use the chosen spelling.
2022-08-03 17:55:34 -07:00
josh11b 6210353dfe Update links to open discussion minutes archives (#1873) 2022-08-01 16:46:19 -07:00
josh11b 64f3284a19 Update links to visible copies of docs (#1786)
I've manually copied some Google docs that were referenced in our design .md files so they may be publicly viewable.
2022-07-27 17:45:05 -07:00
Josh Soref 066b103881 Spelling (#1580)
This PR corrects misspellings identified by the [check-spelling action](https://github.com/marketplace/actions/check-spelling).

The misspellings have been reported at https://github.com/jsoref/carbon-lang/commit/38a1c1640151899fd6da0442a92557f9543b6280#commitcomment-79197316

The action reports that the changes in this PR would make it happy: https://github.com/jsoref/carbon-lang/commit/173c8f9083a68aa61f7cfe94f720f1e5dc7f1ea3

Note: this PR does not include the action. If you're interested in running a spell check on every PR and push, that can be offered separately.

Signed-off-by: Josh Soref <2119212+jsoref@users.noreply.github.com>
2022-07-22 16:14:21 -07:00
Ryan Russell aa4ce80907 docs(design): improve readability (#1431)
Readability improvements focused on `docs/design/.md`

Signed-off-by: Ryan Russell <git@ryanrussell.org>
2022-07-19 17:45:45 -04:00
Jonathan Ross-Perkins a97276bcf7 TODO -> FIXME (#1316)
This is for https://google.github.io/styleguide/cppguide.html#TODO_Comments; FIXME seems to be getting used for the same purpose, and we should probably only have one so that it's easier to scan for.
2022-06-07 10:49:17 -07:00
josh11b 9b028bb743 Destructors (#1154)
Add a way for classes to add custom destructor code:
```
class Class1 {
  // forward declaration
  destructor [me: Self] { ... }
}
// out-of-line definition
destructor Class1 [me: Self] { ... }

class Class2 {
  // can modify `me` as part of destruction
  destructor [addr me: Self*] { ... }
}
base class MyBaseClass {
  virtual destructor [addr me: Self*] { ... }
}
class MyDerivedClass extend MyBaseClass {
  impl destructor [addr me: Self*] { ... }
}
```
and constraints `Concrete`, `Deletable`, `Destructible`, and `TrivialDestructor`.
2022-04-18 17:39:33 -07:00
db66a4350e Generic details 11: operator overloading (#1144)
Operators rewrite to calls of specific operator interface functions, so you overload an operator for a type by implementing an interface for it. There is a `like` operator for defining a set if implementations for supporting implicit conversions more conveniently.

Co-authored-by: Geoff Romer <gromer@google.com>
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
2022-04-08 14:51:49 -07:00
josh11b 5238a8d37a Work around prettier bug (#1150)
Looks like this might be related to prettier/prettier#6112 , but the observed behavior is more broken than that bug indicates.
2022-03-23 13:49:48 -07:00
josh11bandRichard Smith c08cbdb0bd Clarify class declaration syntax (#1026)
Clarify class declaration syntax

Co-authored-by: Richard Smith <richard@metafoo.co.uk>
2022-01-14 14:23:43 -08:00
josh11bandRichard Smith 1534970146 Implicit conversions for aggregates (#981)
Define initialization, assignment, comparison, and implicit conversion between data classes with different field orders and/or types.

Implements the decision made in #710 .

Co-authored-by: Richard Smith <richard@metafoo.co.uk>
2022-01-06 11:16:41 -08:00
Jon Meowandjosh11b 24b763c7e8 Fix or remove invalid anchor links, adding pre-commit (#997)
Co-authored-by: josh11b <josh11b@users.noreply.github.com>
2022-01-05 15:00:02 -08:00
josh11b cfb36b85e5 Merge overview sections (#899) 2021-10-19 11:58:48 -07:00
3610325c38 Inheritance (#777)
This proposal adds inheritance to classes, following this syntax:
```
// Abstract classes may not be instantiated, but
// may have abstract methods and be extended.
abstract class AbstractBaseClass {
  virtual fn CanBeOverridden[me: Self]() -> i32 {
    return me.data;
  }
  abstract fn PureVirtual[me: Self]() -> i32;
  fn Create(data: i32) -> partial Self {
    return {.data = data};
  }
  protected var data: i32;
}

// Classes are final by default
class FinalClass extends AbstractBaseClass {
  impl fn PureVirtual[me: Self]() -> i32 {
    return me.x;
  }
  fn Create(data: i32) -> Self {
    return {.base = AbstractBaseClass.Create(data), .x = 2 * data};
  }
  private var x: i32;
}

// Can be instantiated and extended
base class ExtensibleClass {
  // May optionally use partial types in factory functions
  protected fn CreateAsBase(data: i32) -> partial Self { ... }
  fn Create(data: i32) -> Self { ... }
}
```

Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
2021-09-08 17:37:35 -07:00
josh11bandChandler Carruth 0820dec01f Nominal classes and methods (#722)
Add support for nominal (or "named") classes with encapsulation. Inheritance will be in a later proposal. Here is an example of the proposed syntax:

```
class Circle {
  fn Create(c: Point, r: f32) -> Self {
    return {.center = c, .radius = r};
  }
  fn Diameter[me: Self]() -> f32 {
    return me.radius * 2;
  }
  fn Expand[addr me: Self*](distance: f32);

  private var center: Point;
  private var radius: f32;
}

fn Circle.Expand[addr me: Self*](distance: f32) {
  me->radius += distance;
}
```

Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
2021-08-23 15:45:41 -07:00
36764ff1af Basic classes: use cases, struct literals, struct types, and future work (#561)
This proposal defines the very basics of `class` types, primarily focused on:

-   use cases including: data classes, encapsulated types, inheritance with and without `virtual`, interfaces as base classes, and mixins for code reuse;
-   anonymous data types for called _structural data classes_ or _struct types_. Struct literals are used to initialize class values and ad-hoc parameter and return types with named components; and
-   future work, including the provisional syntax already in use for features that have not been decided.

The intent is to both make some small incremental progress and get agreement on direction. As such it doesn't include things like nominal types, methods, access control, inheritance, etc.

It proposes this struct type and literal syntax:
```
var p: {.x: Int, .y: Int} = {.x = 0, .y = 1};
```
Note that it uses commas (`,`) between fields instead of semicolons (`;`), and no introducer for types or literal values.

Incorporates decisions from #665 , #653 , #651


Co-authored-by: Geoff Romer <gromer@google.com>
Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
2021-08-09 12:28:36 -07:00