Question 1

How do I use PPrint to pretty-print a case class in Scala REPL?

Accepted Answer

Add the PPrint dependency to your project, import pprint._, and use pprint.pprintln(yourCaseClass). It will automatically format the output with proper indentation and structure for better readability in the REPL.

Question 2

PPrint vs Scala's default toString: which is better for debugging nested data?

Accepted Answer

PPrint provides structured, readable output for nested collections and case classes, while toString often produces messy strings. For complex debugging, PPrint is superior, but for simple values, toString is faster and sufficient.

Question 3

Can PPrint format JSON strings directly or do I need a parser?

Accepted Answer

PPrint does not parse JSON; it's designed for Scala values. You should first convert JSON to a Scala data structure using a library like uPickle or Circe, then use PPrint to format it for display.

Question 4

How to customize output width and colors in PPrint?

Accepted Answer

Use the pprint.Config object to set parameters like width, height, and color. For example, pprint.pprintln(value, width=100) adjusts the width, and colors can be enabled via configuration for terminal output.

Question 5

Is PPrint compatible with Scala 3 and new type system features?

Accepted Answer

PPrint is maintained and generally compatible with Scala 3, but check the latest documentation for updates. It supports pretty-printing of new types, though custom printers might require adjustments for Scala 3 specifics.

Question 6

How to add a custom printer for my own classes in PPrint?

Accepted Answer

Define an implicit pprint.PPrinter instance for your type by implementing the render method. Once defined, PPrint will automatically use it when formatting instances of that type, as per the extensible API.

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