When should one use lambdas vs. top-level function...

# codingconventions

[Sam Stone]

When should one use lambdas vs. top-level functions vs. inner functions?

[ephemient]

do you mean top level vs nested classes, or nested classes vs inner classes?

[Sam Stone]

Yes, nested. Corrected.

[Klitos Kyriacou]

Responding to the main question:
• Use top-level functions by default.
• Use an inner function if it is:
◦ very short
◦ only makes sense when used by its enclosing function
◦ is used more than once in the enclosing function
• Use a lambda when it is:
◦ short
◦ only makes sense when used by its enclosing function
◦ is only used once
You can interpolate this principle to nested classes and anonymous classes.

[Sam Stone]

@Klitos Kyriacou are those your own conversations? Have you seen those conventions published anywhere?

[Sam Stone]

And what is the point of storing the lambda in a variable if it is only used once? Just inline the code.

[Klitos Kyriacou]

I haven't seen them published, but I was reporting my observations based on all the Kotlin code I've seen over the past couple of years and seeing what looks readable/unreadable and also seeing what the common idioms seem to be.