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Merged
merged 4 commits into from
Sep 5, 2025
Merged

Link out to the notation from grammar summary #1989

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62286c1
Link out to the notation from grammar summary
epage Sep 4, 2025
fd70409
Add rule identifiers to notation chapter
traviscross Sep 4, 2025
25a4588
Move `input.syntax` to the corresponding chapter
traviscross Sep 5, 2025
7da73b2
Revise link to grammar syntax in grammar summary
traviscross Sep 5, 2025
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2 changes: 1 addition & 1 deletion src/grammar.md
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# Grammar summary

The following is a summary of the grammar production rules.
The following is a summary of the grammar production rules. For details on the syntax of this grammar, see *[notation.grammar.syntax]*.

{{ grammar-summary }}
13 changes: 13 additions & 0 deletions src/input-format.md
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r[input]
# Input format

r[input.syntax]
```grammar,lexer
@root CHAR -> <a Unicode scalar value>

NUL -> U+0000

TAB -> U+0009

LF -> U+000A

CR -> U+000D
```
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This feels a bit odd to reference this as the input syntax (and put it here. I would have expected input.syntax to be something like

@root INPUT -> SHEBANG? (BLANK_LINES FRONTMATTER)? TOKEN*

BLANK_LINES might refer to part of this but not all of it.


r[input.intro]
This chapter describes how a source file is interpreted as a sequence of tokens.

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30 changes: 9 additions & 21 deletions src/notation.md
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r[notation]
# Notation

r[notation.grammar]
## Grammar

r[notation.grammar.syntax]

The following notations are used by the *Lexer* and *Syntax* grammar snippets:

| Notation | Examples | Meaning |
Expand All @@ -26,7 +30,8 @@ The following notations are used by the *Lexer* and *Syntax* grammar snippets:

Sequences have a higher precedence than `|` alternation.

## String table productions
r[notation.grammar.string-tables]
### String table productions

Some rules in the grammar &mdash; notably [unary operators], [binary
operators], and [keywords] &mdash; are given in a simplified form: as a listing
Expand All @@ -40,30 +45,13 @@ When such a string in `monospace` font occurs inside the grammar,
it is an implicit reference to a single member of such a string table
production. See [tokens] for more information.

## Grammar visualizations
r[notation.grammar.visualizations]
### Grammar visualizations

Below each grammar block is a button to toggle the display of a [syntax diagram]. A square element is a non-terminal rule, and a rounded rectangle is a terminal.

[syntax diagram]: https://en.wikipedia.org/wiki/Syntax_diagram

## Common productions

The following are common definitions used in the grammar.

r[input.syntax]
```grammar,lexer
@root CHAR -> <a Unicode scalar value>

NUL -> U+0000

TAB -> U+0009

LF -> U+000A

CR -> U+000D
```

[binary operators]: expressions/operator-expr.md#arithmetic-and-logical-binary-operators
[keywords]: keywords.md
[syntax diagram]: https://en.wikipedia.org/wiki/Syntax_diagram
[tokens]: tokens.md
[unary operators]: expressions/operator-expr.md#borrow-operators