the authors wrote a paper compraing it to sicp. https://users.cs.northwestern.edu/~robby/pubs/papers/htdp-si...

There is another book that is usually mentioned when comparing these two. Concepts, Techniques and Models of Computer Programming. I don't know how they all compare to each other, I just mention it for completeness sake.

https://www.info.ucl.ac.be/~pvr/book.html

i havent read this book but i skimmed the toc and i have to say its probably even harder than sicp. http://www.info.ucl.ac.be/people/PVR/booktoc.pdf

There is another book which isn't often mentioned, which I like to consider "SICP-lite", Concrete Abstractions: https://gustavus.edu/mcs/max/concrete-abstractions.html

This is a great book and uses a back then obscure, today defunct programming language Oz.

https://en.m.wikipedia.org/wiki/Oz_(programming_language)

an updated version that uses a current language would be nice, but the book isnt even open source (i.e. under the Creative Commons license)

Would it be easy to follow the book using Mercury language?

Years ago, the author taught a MOOC covering parts of the book[0]. The course is archived on edX, and the videos are on YouTube[1]. It was fun starting from a super simple functional language and building to a dataflow functional language by the end.

[0] https://www.edx.org/course/paradigms-of-computer-programming...

[1] https://www.youtube.com/playlist?list=PLw454N-VXALSIzIe_eL5U...

much easier to read, less tedious math/engineering stuff.