The Hidden DSL in Catalyst
How Spark’s internal rewriting framework, Catalyst, exposes an embedded DSL with a public extension surface, the same one Delta Lake and Iceberg use to plug into the optimizer pipeline.
Compilers
A Small Compiler for Explaining Delta Lake Pruning
How delta-explain turns one predicate and the Delta log into a trustworthy explanation of file pruning, through shared representation, safe rewrites, and conservative measurement.