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Agree.

I'm writing Scheme R5RS in Kotlin (https://github.com/kovrik/scheme-in-kotlin) and have implemented everything except macros (6).

Have no idea how to beat them.

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Just think of them as defining functions that take s expressions in and spit s expressions out before “normal” runtime evaluation and which hence only see built in symbols.

Yes, I get that (in general).

But then there are things like hygiene, performance and some tricky edge-cases.

And I couldn't find any standard (and simple) algorithm to implement macros (preferably written in something other than Scheme itself).

Still trying to wrap my head around.

"This paper describes a modified form of Kohlbecker’s algo- rithm for reliably hygienic (capture-free) macro expansion in block-structured languages, where macros are source-to- source transformations specified using a high-level pattern language."

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.464...

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