cl-debugger-hook: mutable global (fn (c hook) result); cl-invoke-debugger
calls it with infinite-recursion guard (sets hook nil during call).
cl-error now routes unhandled errors through cl-invoke-debugger instead of
bare host error — allows the hook to invoke a restart and resume.
cl-break-on-signals: when set to a type name, cl-signal fires the debugger
hook before walking handlers if the condition matches.
cl-invoke-restart-interactively: calls the restart fn with no args (no
terminal protocol — equivalent to (invoke-restart name)).
4 new tests in conditions.sx covering all three; Phase 3 fully complete.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
define-condition with 15-type ANSI hierarchy (condition/error/warning/
simple-error/simple-warning/type-error/arithmetic-error/division-by-zero/
cell-error/unbound-variable/undefined-function/program-error/storage-condition).
cl-condition-of-type? walks the hierarchy; cl-make-condition builds tagged
dicts {:cl-type "cl-condition" :class name :slots {...}}. cl-signal-obj
walks cl-handler-stack for non-unwinding dispatch. cl-handler-case and
cl-restart-case use call/cc escape continuations for unwinding. All stacks
are mutable SX globals (the built-in handler-bind/restart-case only accept
literal AST specs — not computed lists). Key fix: cl-condition-of-type?
captures cl-condition-classes at define-time via let-closure to avoid
free-variable failure through env_merge parent chain.
55 tests in lib/common-lisp/tests/conditions.sx, wired into test.sh.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Type predicates, arithmetic, chars (inline α/digit/case),
format, gensym, values, sets, radix, list utilities.
cl-empty? guards all list traversal against () vs nil in sx_server.
Load spec/stdlib.sx in test.sh to expose format.
Fix lib/r7rs.sx number->string to use (= (len r) 0) not (nil? r).
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
