We saw that you can calculate simple number expressions with operators like
For Booleans we have operators
You can also concatenate a value to a String with
But in real programs you "don't invent the wheel", you rely on existing code. We need to "store" that code somewhere, and parametrize it with variables. That is what functions are for!
FlowRun provides lots of useful function out of the box. You can probably guess what some of them do. Try to output these expressions:
The syntax is simple: you write a function name, and in parens you write its arguments separated by commas. Of course, you can have a function with zero arguments.
In the expressions above, we say that we call or invoke a function.