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Mar 8, 2022
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Tighten unary op syntax and untupling language #14372

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6e84331
Tighten unary op syntax and untupling language
som-snytt Jan 28, 2022
60f85f4
Less blabbing per review
som-snytt Feb 25, 2022
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14 changes: 11 additions & 3 deletions docs/_docs/reference/changed-features/operators.md
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Expand Up @@ -6,9 +6,12 @@ movedTo: https://docs.scala-lang.org/scala3/reference/changed-features/operators

The rules for infix operators have changed in some parts:

First, an alphanumeric method can be used as an infix operator only if its definition carries an `infix` modifier. Second, it is recommended (but not enforced) to
augment definitions of symbolic operators with [`@targetName` annotations](../other-new-features/targetName.md). Finally,
a syntax change allows infix operators to be written on the left in a multi-line expression.
First, an alphanumeric method can be used as an infix operator only if its definition carries an `infix` modifier.

Second, it is recommended (but not enforced) to augment definitions of symbolic operators
with [`@targetName` annotations](../other-new-features/targetName.md).

Finally, a syntax change allows infix operators to be written on the left in a multi-line expression.

## The `infix` Modifier

Expand Down Expand Up @@ -163,3 +166,8 @@ Another example:

This code is recognized as three different statements. `???` is syntactically a symbolic identifier, but
neither of its occurrences is followed by a space and a token that can start an expression.

## Unary operators

A unary operator must not have explicit parameter lists even if they are empty.
A unary operator is a method named "unary_`op`" where `op` is one of `+`, `-`, `!`, or `~`.
6 changes: 3 additions & 3 deletions docs/_docs/reference/other-new-features/parameter-untupling.md
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Expand Up @@ -39,9 +39,9 @@ def combine(i: Int, j: Int) = i + j
xs.map(combine)
```

Generally, a function value with `n > 1` parameters is converted to a
pattern-matching closure using `case` if the expected type is a unary
function type of the form `((T_1, ..., T_n)) => U`.
Generally, a function value with `n > 1` parameters is wrapped in a
function type of the form `((T_1, ..., T_n)) => U` if that is the expected type.
The tuple parameter is decomposed and its elements are passed directly to the underlying function.

More specifically, the adaptation is applied to the mismatching formal
parameter list. In particular, the adaptation is not a conversion
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