(:field rec) / (get rec :field) lowers to (jolt-get rec kw), which walked the
get-arm list to reach the jrec arm, then did jrec-has? + jrec-lookup — TWO linear
scans, each comparing keys through the generic jolt=2 equality dispatcher. Field
keys are interned keywords, so:
- jrec-key=? compares a keyword query by eq? (jolt=2 only for non-keyword keys),
- jrec-ref does ONE scan (vs has?+lookup) and runs a deftype's ILookup valAt only
when the field is genuinely absent (present-nil still returns nil, not default),
- jolt-get-dispatch checks jrec? first, skipping the get-arm walk for the hottest
get target. jrec-lookup/jrec-has? (used by =, contains?, etc.) get the fast
compare too.
binary-trees 135x->18.9x, dispatch 121x->26.4x, mono-dispatch 327x->108x vs JVM.
Runtime .ss (collections.ss + records.ss), no re-mint; make test + shakesmoke +
buildsmoke green, record get/assoc/keys/=/count semantics unchanged.