The cond special form misclassified Clojure-style as scheme-style when
the first test was a 2-element list like (nil? x) — treating it as a
scheme clause ((test body)) instead of a function call. Define
cond-scheme? using every? to check ALL clauses, fix eval.sx sf-cond and
render.sx eval-cond, rewrite engine.sx parse-time/filter-params as
nested if to avoid the ambiguity, add regression tests across eval/
render/aser specs. 378/378 tests pass.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>