Trends in Functional Programming

This book constitutes revised selected papers from the 21st International Symposium on Trends in Functional Programming, TFP 2020, which was held in Krakow, Poland, during February 13-14, 2020. The 11 full papers presented in this volume were carefully reviewed and selected from 22 submissions. They were organized in topical sections named: domain-specific languages; debugging and testing; reasoning and effects; and parallelism.