+> Skeleton
infix +>
+>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 multiplicative precedence level, left-associative.
That is level 7 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 #
*, /, div, %, %%, mod, +&, +<, ~&, ~<, ~>, ?&, gcd, lcm.
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.
1 of 7 of these disagree between Raku++ and Rakudo — shown side by side below. A disagreement here is a defect report waiting to be written, not a documented rule.
| Expression | Raku++ | Rakudo |
|---|---|---|
1 +> 2 | Int | 0 | |
"a" +> "b" | Int | 0 | ERR Cannot convert string to number: base-10 number must begin with valid digits or '.' in '<HERE>a' (indicated by <HERE>) |
1 +> "2" | Int | 0 | |
(1, 2) +> (3, 4, 5) | Int | 0 | |
True +> False | Int | 1 | |
Nil +> 1 | Int | 0 | |
1/2 +> 1/3 | Rat | 0 | |