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Comment by cosmic_quanta | Hacker News Reader

To be fair, you can printf debug anywhere (Debug.Trace module). I'm the "print to debug" kind of guy, and I can debug in Haskell just like in Python using this.

I think the issue you have stems from the fact that people can't transfer the knowledge from C/C++/Python/wtv directly. One of the standard way to build programs in Haskell (mtl-style) allows you to perform IO actions almost anywhere, provided you're willing to play with monads. But this is so different from anything most people have ever seen that I understand why it can be frustrating.

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"Haskell's trace function is a refreshing desert in the oasis of referential transparency." --Audrey Tang

Any idea when this was added? I am relatively certain that it was not possible in Haskell 98, and admittedly most of my Haskell experience is a decade old.

I have picked up three well-regarded Haskell books over the past decade trying to get back into the language, and don't recall any mention of this capability.

That's another issue, the dearth of anything like tutorials or books on how to do something practical with Haskell, rather than the whirlwind tour of language features. I keep being told that serious software is being built in Haskell, but the knowledge of how to get from university-grade code to production-grade code is an unmarked wilderness that everyone must apparently navigate on their own.

Looking back on historical GHC releases, the earliest one available on the web page is version 0.29, released in July 1995, and it already has the trace function. I would guess has been there for a long time.

The license on the Debug.Trace module says 2001... That's all I know.

I'm a big fan of the "Haskell Programming from First Principles" book. I read it on-and-off over the course of 2 years, and I think I'm an intermediate Haskell user at this point.

The most production-grade Haskell software I've ever played with would be Pandoc (document conversion) and the Yesod family of webdev libraries. Playing with Yesod is a bit scarier because it uses some Template Haskell magic. On the flip side, there's a great user guide (the "Yesod book").

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