> Say we agree on the syntax above
>> ($n) |$m| => $m * $n;
> What happens when my one liner function needs to do one more operation
> like checking the value of $n before multiplication?
As I stated before suggesting the syntax: It's only meant for a single
expression. It's purposefully NOT intended to cover multiple
expressions. In that case the current (verbose) syntax is better for
all criteria I care about. Additionally, neither Python nor Dart
allows multiple expressions in their short-syntax functions.