[tredontho]

We use a bit of a dated version of Gosu where I work (something I never thought I'd get to claim on HN...), but I believe that curly braces are perfectly fine to use, and actually required if you have a multi-statement block (essentially starting to look like anonymous functions in Javascript).

[lboasso]

Exactly if you want to return just an expression you can avoid them, otherwise if you use statements in the body of the lambda you need curly braces.

[perlgeek]

OK, thank you both for the explanation. That does sound sane :-).