Understanding Swift Functions (Arguments)

When Swift2 changed to Swift3, the calling convention of the function was changed.Swift2 omitted the argument name label by default for the first argument only (which was close to Objective-C naming convention), but Swift3 needed to label the first argument with an external argument name to prioritize grammatical consistency.

https://github.com/apple/swift-evolution/blob/master/proposals/0046-first-label.md

In other words, areaOfTrianableWithBase(3,andHeight:4) is correct on Swift2, but compilation error on Swift3.

Correctly label the first argument with an external argument name and call it as follows:

areaOfTribleWithBase(base:3, andHeight:4)