The top-level of this repository contains the source code for various proposals and the generated/ directory contains the generated proposals (HTML or PDF).

This repository also includes a paper-writing framework using Pandoc.

• P1371: Pattern Matching
• P1469: Disallow _ Usage in C++20 for Pattern Matching in C++23
• P1260: Pattern Matching - Requested to unify with P1308
• P0655: visit<R>: Explicit Return Type for visit - Accepted in C++20
• D0080: Tweaks to the Kona Variant - Encouraged to return with P-papers
• P0080: Variant: Discriminated Union with Value Semantics - Not presented
• N3887: Consistent Metafunction Aliases - Accepted in C++14

make <paper>.pdf  # `<paper>.md` -> `generated/<paper>.pdf`
make <paper>.html # `<paper>.md` -> `generated/<paper>.html`

git submodule add https://github.com/mpark/wg21.git

echo "include wg21/Makefile" > Makefile

make <paper>.pdf  # `<paper>.md` -> `generated/<paper>.pdf`
make <paper>.html # `<paper>.md` -> `generated/<paper>.html`

This framework provides support for various common elements for C++ papers.

• Title
• Table of Contents
• Markdown
  • Within Code Blocks
• Tony Tables
• Proposed Wording
  • Paragraph Numbers
  • Code Changes
  • Wording Changes
  • Grammar Changes
• Citations
• References
  • Automatic References
  • Manual References
• Unicode Considerations

The title is specified in a YAML metadata block.

date: today will generate today's date in YYYY-MM-DD (ISO 8601) format.

YAML lists can be used to specify multiple audiences and authors:

---
title: Integration of chrono with text formatting
document: P1361R0
date: 2018-10-16
audience:
  - Library Evolution Working Group
  - Library Working Group
author:
  - name: Victor Zverovich
    email: <victor.zverovich@gmail.com>
  - name: Daniela Engert
    email: <dani@ngrt.de>
  - name: Howard E. Hinnant
    email: <howard.hinnant@gmail.com>
---

The default toc-depth is 3, but it can be specified to go deeper:

Refer to the full Pandoc Markdown spec for useful extensions!

Within ```, ```cpp, and ```diff code blocks, any text surrounded by the @ symbol is formatted as Markdown! This is useful for conventions such as see below, unspecified, and exposition-only variable names.

Tony Tables are fenced Div blocks that open with ::: tonytable and close with :::. Fenced code blocks are the only elements that actually get added to Tony Tables, except that the last header (if any) before a fenced code block is attached to the cell above. Each code block is pushed onto the current row.

::: tonytable

### Before
```cpp
switch (x) {
  case 0: std::cout << "got zero"; break;
  case 1: std::cout << "got one"; break;
  default: std::cout << "don't care";
}
```

### After
```cpp
inspect (x) {
  0: std::cout << "got zero";
  1: std::cout << "got one";
  _: std::cout << "don't care";
}
```

:::

Each fenced code block is pushed onto the current row, and horizontal rules (---) are used to move to the next row.

::: tonytable

### Before
```cpp
switch (x) {
  case 0: std::cout << "got zero"; break;
  case 1: std::cout << "got one"; break;
  default: std::cout << "don't care";
}
```

### After
```cpp
inspect (x) {
  0: std::cout << "got zero";
  1: std::cout << "got one";
  _: std::cout << "don't care";
}
```

---

```cpp
if (s == "foo") {
  std::cout << "got foo";
} else if (s == "bar") {
  std::cout << "got bar";
} else {
  std::cout << "don't care";
}
```

```cpp
inspect (s) {
  "foo": std::cout << "got foo";
  "bar": std::cout << "got bar";
  _: std::cout << "don't care";
}
```

:::

Paragraph numbers are bracketed Span elements that look like: [2]{.pnum} and [2.1]{.pnum}.

[2]{.pnum} An expression is _potentially evaluated_ unless it is an unevaluated
operand (7.2) or a subexpression thereof. The set of _potential results_ of
an expression `e` is defined as follows:

- [2.1]{.pnum} If `e` is an _id-expression_ (7.5.4), the set contains only `e`.
- [2.2]{.pnum} If `e` is a subscripting operation (7.6.1.1) with an array operand,
the set contains the potential results of that operand.

Large changes are fenced Div blocks with ::: add for additions, ::: rm for removals.

Small, inline changes are bracketed Span elements that looks like [<new text>]{.add} or [<old text>]{.rm}.

Use line blocks (|) in order to preserve the leading spaces.

> | _selection-statement:_
> |     `if constexpr`_~opt~_ `(` _init-statement~opt~_ _condition_ `)` _statement_
> |     `if constexpr`_~opt~_ `(` _init-statement~opt~_ _condition_ `)` _statement_ `else` _statement_
> |     `switch (` _init-statement~opt~_ _condition_ `)` _statement_
> |     [`inspect` `constexpr`~_opt_~ `(` _init-statement~opt~_ _condition_ `)` `{`
>            _inspect-case-seq_
>        `}`]{.add}
>
> ::: add
> | _inspect-case-seq:_
> |     _inspect-case_
> |     _inspect-case-seq_ _inspect-case_
>
> | _inspect-case:_
> |     _attribute-specifier-seq~opt~_ _inspect-pattern_ _inspect-guard~opt~_ `:` _statement_
>
> | _inspect-pattern:_
> |     _wildcard-pattern_
> |     _identifier-pattern_
> |     _constant-pattern_
> |     _structured-binding-pattern_
> |     _alternative-pattern_
> |     _binding-pattern_
> |     _extractor-pattern_
>
> | _inspect-guard:_
> |     `if (` _expression_ `)`
> :::

In-text citations look like this: [@<id>]

The bibliography is automatically generated from https://wg21.link/index.yaml for citations of the following types.

The [@N3546] example from Citations generates:

Use make update to update the local cache of index.yaml.

Manual references are specified in a YAML metadata block similar to Title, typically at the bottom of the document.

The `id` field is for in-text citations (e.g., [@PAT]),
and `citation-label` is the label for the reference.

Typically `id` and `citation-label` are kept the same.

---
references:
  - id: PAT
    citation-label: Patterns
    title: "Pattern Matching in C++"
    author:
      - family: Park
        given: Michael
    URL: https://github.com/mpark/patterns
---

If you build for LaTeX output, and you have Unicode characters in any of your paper's source code, you may have problems. First of all, the default pdf engine simply does not support Unicode characters at all. You can add --pdf-engine=xelatex to the call to pandoc in the Makefile to use xelatex as your engine instead. That gives you access to some font selections for different parts of your paper (see the Fonts section of the Pandoc manual at https://pandoc.org/MANUAL.html#fonts). The option that controls your source code fonts is monofont. You can add a line with your monofont choice to your YAML metadata block. Here, it's "DejaVu Sans Mono" which provides glyphs for a large amount of the Unicode characters:

---
title: Integration of chrono with text formatting
document: P1361R0
date: 2018-10-16
audience:
  - Library Evolution Working Group
  - Library Working Group
author:
  - name: Victor Zverovich
    email: <victor.zverovich@gmail.com>
  - name: Daniela Engert
    email: <dani@ngrt.de>
  - name: Howard E. Hinnant
    email: <howard.hinnant@gmail.com>
monofont: "DejaVu Sans Mono"
---

If you want the list of available fonts on your system, most supported systems will produce a list via the command-line tool fc-list.

• P1361: Integration of chrono with text formatting
• P1390: Suggested Reflection TS NB Resolutions

• pdflatex
• pandoc (>= 2.7.3)
• pandoc-citeproc
• python3
• panflute

brew cask install mactex
brew install pandoc pandoc-citeproc python
pip3 install panflute

Manually install the latest pandoc release following their instructions.

sudo apt-get install texlive-latex-base
pip3 install panflute

Debian installation may require these additional packages:

• texlive-fonts-recommended
• texlive-latex-recommended
• texlive-latex-extra

• Blog Post: How I format my C++ papers
• Lightning Talk @ C++Now 2019: WG21 Paper in Markdown