Debuggin single lines in Scala

Question

A single of code can achieve a lot in Scala.

def -(that: Nat) = if (that.isZero) this else throw new Error("negative number")

However, it is difficult to debug. Any tips?

om-nom-nom · Answer 1 · 2013-04-18T21:05:39.980

4

Use scala worksheet. That's it: you'll get multiline REPL with your environment in which you can play with your code.

enter image description here Alternatively, just use REPL bundled with sbt (sbt console) with proper imports

edited Apr 18 '13 at 21:05

answered Apr 18 '13 at 21:00

om-nom-nom

Thanks but what about for tonnes of existing code that is in scala objects / classes? – More Than Five Apr 18 '13 at 21:27
1

@MoreThanFive nothing special: use debugger & logging output, just like usually. – om-nom-nom Apr 18 '13 at 21:43

score -1 · Answer 2 · edited Jun 20 '20 at 09:12

-1

you can see output of compiler phases, i.e. the AST after desugarings with

scalac -Xprint:typer

scalac -Xprint-types (note hyphen, not colon)

The man page is a little confusing, there's no "typer" phase listed, but it works:

edited Jun 20 '20 at 09:12

Community

answered Apr 19 '13 at 00:16

Gene T

2 Answers2