The method io.cequence.openaiscala.service.GuiceContainer.terminate has return type Unit but is declared without parentheses. The Scala style guide states that methods without parentheses should only be used when the method has no side effects. Here the terminate method calls terminate() on the ActorSystem and thus it has side effect.
In general, methods which have Unit return type should always declared with parentheses (since if they do not have side effects they are not doing anything at all).
"However, this syntax (leaving off parentheses) should only be used when the method in question has no side-effects (purely-functional). In other words, it would be acceptable to omit parentheses when calling queue.size, but not when calling println() (or openGarageDoor()). This convention mirrors the method declaration convention given above.”
“Religiously observing this convention will dramatically improve code readability and will make it much easier to understand at a glance the most basic operation of any given method. Resist the urge to omit parentheses simply to save two characters!”
I am using JetBrains IntelliJ as an IDE, and it reports this is a warning in the editor:
Warning:(21, 17) Method with Unit result type is parameterless
The method
io.cequence.openaiscala.service.GuiceContainer.terminatehas return typeUnitbut is declared without parentheses. The Scala style guide states that methods without parentheses should only be used when the method has no side effects. Here the terminate method callsterminate()on the ActorSystem and thus it has side effect.In general, methods which have Unit return type should always declared with parentheses (since if they do not have side effects they are not doing anything at all).
See https://alvinalexander.com/source-code/scala-style-use-parentheses-methods-side-effects/:
"However, this syntax (leaving off parentheses) should only be used when the method in question has no side-effects (purely-functional). In other words, it would be acceptable to omit parentheses when calling queue.size, but not when calling println() (or openGarageDoor()). This convention mirrors the method declaration convention given above.”
“Religiously observing this convention will dramatically improve code readability and will make it much easier to understand at a glance the most basic operation of any given method. Resist the urge to omit parentheses simply to save two characters!”
I am using JetBrains IntelliJ as an IDE, and it reports this is a warning in the editor:
See first example here: https://blog.jetbrains.com/scala/2011/03/10/signature-matters/
Also note that in source of ActorSystem.terminate() it is declared with parantheses.
See also #22.