Rules / Operators / junctive and

& Skeleton

infix &

&
infixjunctive and 11/27list-assocRaku++ runs this — matches Rakudo on all 7docs.raku.org ↗

The rules for & have not been written yet. Everything below is extracted rather than authored: the official documentation supplies the classification, and the interpreters were asked directly about the rest.

What is established #

Classification #

& is parsed as an infix at the junctive and precedence level, list-associative.

That is level 11 of 27 on the ladder, counting from the tightest. Operators sharing a level bind equally; grouping among them is decided by associativity alone.

Shares its precedence level with #

, .

These all bind equally tightly, so an expression mixing them groups by associativity alone.

What the interpreter said #

Raku++ parses this spelling. Asked to compile:

my $a = 6; my $b = 3; sink($a & $b)

…it got through the parser. On its own that establishes very little: it says nothing about whether the construct executes, let alone whether the result is right. Where the behaviour table below exists, that is the stronger evidence — those expressions were actually run.

Covered upstream #

The official documentation has a section for this construct: docs.raku.org. Until the rules here are written, that is the better reference.

Observed behaviour #

Each expression below was executed by both interpreters when this page was built; the results are recorded, not written. The operands are chosen to cross the boundaries that catch people out: string against number, a list where a scalar was meant, a boolean, an undefined value, and an exact rational.

Raku++ and Rakudo agree on every row below.

ExpressionRaku++Rakudo
1 & 2Junction | all(1, 2)
"a" & "b"Junction | all(a, b)
1 & "2"Junction | all(1, 2)
(1, 2) & (3, 4, 5)Junction | all((1 2), (3 4 5))
True & FalseJunction | all(True, False)
Nil & 1Junction | all(Nil, 1)
1/2 & 1/3Junction | all(0.5, 0.333333)