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Grammar for tuple and tuple indexing expressions #263

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Mar 12, 2018
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Grammar for tuple and tuple indexing expressions #263

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Grammar for tuple and tuple indexing expressions
brauliobz Mar 10, 2018
a9d6907
Adjustments after review:
brauliobz Mar 11, 2018
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14 changes: 14 additions & 0 deletions src/expressions/tuple-expr.md
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Expand Up @@ -2,6 +2,13 @@

## Tuple expressions

> **<sup>Syntax</sup>**
> _TupleExpression_ :
> &nbsp;&nbsp; &nbsp;&nbsp; `(` `)`
> &nbsp;&nbsp; | `(` [_Expression_] `,` `)`
> &nbsp;&nbsp; | `(` [_Expression_] (`,` [_Expression_] )<sup>\+</sup>
> `,`<sup>?</sup> `)`
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These two can be merged into `(` [_Expression_] `,` `)` <sup>\+</sup> [_Expression_]<sup>?</sup> `)`


Tuples are written by enclosing zero or more comma-separated expressions in
parentheses. They are used to create [tuple-typed](types.html#tuple-types)
values.
Expand All @@ -22,6 +29,10 @@ comma:

## Tuple indexing expressions

> **<sup>Syntax</sup>**
> _TupleIndexingExpression_ :
> &nbsp;&nbsp; [_Expression_] `.` [INTEGER_LITERAL]
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This can be TUPLE_INDEX

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Fixed. That's correct, but it's like the lexer is aware of context... which is strange. But yeah, the parser is the one that disallows prefixes, suffixes and nonzero numbers beginning in zero.


[Tuples](types.html#tuple-types) and [struct tuples](items/structs.html) can be
indexed using the number corresponding to the position of the field. The index
must be written as a [decimal literal](tokens.html#integer-literals) with no
Expand All @@ -36,3 +47,6 @@ assert_eq!(pair.1, 2);
let unit_x = Point(1.0, 0.0);
assert_eq!(unit_x.0, 1.0);
```

[INTEGER_LITERAL]: tokens.html#integer-literals
[_Expression_]: expressions.html