# Comments

# Table of contents

• Overview
• Details
• Alternatives considered
• References

# Overview

A comment is a lexical element beginning with the characters // and running to the end of the line. We have no mechanism for physical line continuation, so a trailing \ does not extend a comment to subsequent lines.

# Details

In the comments after the // a whitespace character is required to make the comment valid. Newline is a whitespace character, so a line containing only // is a valid comment. The end of the file also constitutes whitespace.

All comments are removed prior to formation of tokens.

Example:

// This is a comment and is ignored. \
This is not a comment.

var Int: x; // error, trailing comments not allowed

Currently no support for block comments is provided. Commenting out larger regions of human-readable text or code is accomplished by commenting out every line in the region.

# Alternatives considered

• Intra-line comments
• Multi-line text comments
• Block comments
• Documentation comments
• Code folding comments

# References

• Proposal #198: Comments