Evaluation order and nontermination in query languages

https://www.rntz.net/post/2026-06-11-datalog-nontermination.html

by luu • 21 days ago

44 6 21 days ago

veqq2• 16 days ago

https://codeberg.org/veqq/declarative-dsls is built around a query language working on tables/dataframes, hashmaps, arrays, strings etc. in the same way. I ended up allowing things like :where :group-by etc. in `select` go in any order and then allowing you to use ->> macros to micromanage the execution order.

bruce343434• 16 days ago

    :set {:job "Engineer"}
    :where |(= ($ :job) "Developer")

What is going on there in that where syntax?

veqq2• 12 days ago

|(...) is the same as (fn ...) making an anonymous function. $ is an argument (in a 1 arity anonymous function.) $ is getting the whole row which is a hashmap and e.g. ({:key "value"} :key) is a way of retrieving from a hashmap. So it's "where value in column job is "Developer".

_alternator_• 16 days ago

A quick skim of the article suggests it's a study of the implications of allowing query planning in programs which are notionally finite but may have unbounded computation. Interesting.

eru• 16 days ago

Evaluation order and nontermination in query languages

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