This was some quick research on something that I found interesting. Was trying to solve a problem, but this might be overkill. It is intersting though!

CPD

Duplicate code can be hard to find, especially in a large project. But PMD’s Copy/Paste Detector (CPD) can find it for you!

CPD works with Java, JSP, C/C++, C#, Go, Kotlin, Ruby, Swift and many more languages. It can be used via command-line, or via an Ant task. It can also be run with Maven by using the cpd-check goal on the Maven PMD Plugin.

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It says it support Python, EcmaScript(JavaScript), C/C++ and more, but these are what I would want, so ...

It seems to be a command-line tool, so should be easy to use.

• repo
• documentation

other solutions

• A Usable Copy-Paste Detector in A Few Lines of Python
  • a description on how to do this
  • they used some library (can't remember now) and did this with Python 2.x
  • was a hybrid system that used tokens rather than ASTs like many others
  • not sure if it would be doable with Python 3.x, but ... Would take some time to see.
• jscpd
  • it says it supports JavaScript, Python, C++, and others. Looks like it's a Node based tool, so ...
  • It also has a CLI.
  • looks like there is a VSCode plugin that can be added
• jsinspect
  • Ranga pointed me to this one, which started all of this. This tool seems to be only JavaScript though
  • apparently there is a browser plug-in for this
• lizard
  • homepage - can enter code here on browser for "Try Lizard in Your Browser"
  • released in 2020/10
  • Supports Python, JS, C/C++, and others.
  • Does more than copy/paste duplication detection.

Might be something to come back to at a later date.