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kotlinlang

Is the Visitor pattern still considered the best approach for processing multiple separate annotations to build one or more files?

My personal opinion is that people run into trouble using the visitor pattern (example here:  <https://kotlinlang.slack.com/archives/C013BA8EQSE/p1739901958510509?thread_ts=1739890854.058929&amp;cid=C013BA8EQSE>). I think a find-transform-write style pipeline works better.

One of the best things you can do when you write a processor is checkout some of the code for the famous ones and base your implementation on those, at least at a very high level. Often these will forgo using the visitor pattern.

<https://github.com/square/moshi/blob/master/moshi-kotlin-codegen/src/main/java/com/squareup/moshi/kotlin/codegen/ksp/JsonClassSymbolProcessorProvider.kt|https://github.com/square/moshi/blob/master/moshi-kotlin-codegen/src/main/java/com[…]up/moshi/kotlin/codegen/ksp/JsonClassSymbolProcessorProvider.kt>

<https://github.com/evant/kotlin-inject/blob/main/kotlin-inject-compiler/ksp/src/main/kotlin/me/tatarka/inject/compiler/ksp/InjectProcessor.kt>