-- Closure-bind: HOFs (srt, map, flt, fld) accept an optional ctx arg
-- that is passed to every invocation of the fn.
--
-- Pattern shown: sort symbols by an external priority lookup map.
-- Without closure-bind, you'd have to zip the priority into each element
-- (records of {sym, pri}) before sorting, then unzip after — recurring
-- per-program tax that closure-bind removes.
-- Key fn: takes element + ctx (the lookup map). Missing keys sort last.
pri sym:t m:M t n>n;r=mget m sym;?r{n v:v;_:99999}
-- 3-arg srt: srt key-fn ctx xs
top pri-map:M t n syms:L t>L t;srt pri pri-map syms
-- Build a small priority map and sort by it.
main>L t;m=mset mmap "a" 2;m=mset m "b" 3;m=mset m "c" 1;top m ["a","b","c"]
-- map closure-bind: enrich each symbol with its price via lookup
look sym:t pm:M t n>n;r=mget pm sym;?r{n v:v;_:0}
prices pm:M t n syms:L t>L n;map look pm syms
prices-demo>L n;m=mset mmap "a" 10;m=mset m "b" 20;prices m ["a","b","a"]
-- jit lacks HOF dispatch entirely (see regression_builtins_as_hof.rs).
-- vm + cranelift route closure-bind through the tree-bridge from PR 3c.
-- engine-skip: jit
-- run: main
-- out: [c, a, b]
-- run: prices-demo
-- out: [10, 20, 10]