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https://github.com/carbon-language/carbon-lang.git
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Aswin Shailajan
33f26bd37b
The [Comments #198](https://github.com/carbon-language/carbon-lang/pull/198) got accepted but the details were not updated in the design docs. Added `comments.md` file to add the details of the proposal and its discussion. Closes #1994
59 lines
1.7 KiB
Markdown
59 lines
1.7 KiB
Markdown
# Comments
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<!--
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Part of the Carbon Language project, under the Apache License v2.0 with LLVM
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Exceptions. See /LICENSE for license information.
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SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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-->
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<!-- toc -->
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## Table of contents
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- [Overview](#overview)
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- [Details](#details)
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- [Alternatives considered](#alternatives-considered)
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- [References](#references)
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<!-- tocstop -->
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## Overview
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A comment is a lexical element beginning with the characters `//` and running to
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the end of the line. We have no mechanism for physical line continuation, so a
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trailing `\` does not extend a comment to subsequent lines.
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## Details
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In the comments after the `//` a whitespace character is required to make the
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comment valid. Newline is a whitespace character, so a line containing only `//`
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is a valid comment. The end of the file also constitutes whitespace.
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All comments are removed prior to formation of tokens.
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Example:
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```
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// This is a comment and is ignored. \
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This is not a comment.
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var Int: x; // error, trailing comments not allowed
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```
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Currently no support for block comments is provided. Commenting out larger
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regions of human-readable text or code is accomplished by commenting out every
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line in the region.
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## Alternatives considered
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- [Intra-line comments](/proposals/p0198.md#intra-line-comments)
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- [Multi-line text comments](/proposals/p0198.md#multi-line-text-comments)
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- [Block comments](/proposals/p0198.md#block-comments-2)
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- [Documentation comments](/proposals/p0198.md#documentation-comments)
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- [Code folding comments](/proposals/p0198.md#code-folding-comments)
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## References
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- Proposal
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[#198: Comments](https://github.com/carbon-language/carbon-lang/pull/198)
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