Chez: runtime eval / load-string / defmacro on the zero-Janet spine

The compiler image is already resident at runtime on the Chez spine, so eval
and load-string are just wiring: make them clojure.core functions instead of
analyzer special forms.

- eval / load-string are now functions, not special forms. Dropped "eval" from
  the host-contract special-symbol lists so it resolves as an ordinary var, and
  def-var! both in compile-eval.ss. eval takes an already-read form (e.g. from
  quote/list) and compiles+evals it in the current ns; load-string reads every
  form from a source string and evals each, returning the last.
- Runtime defmacro: jolt-compile-eval-form intercepts a (defmacro ...) form
  before analysis, defs the expander fn + mark-macro!s the var, exactly as
  emit-image.ss does at build time. The two helpers (macro-form? / defmacro->fn)
  move to compile-eval.ss and emit-image.ss reuses them.
- Top-level (do ...) is now unrolled form-by-form, like Clojure, so a defmacro
  or def in an earlier subform is visible (macro flag set / var interned) before
  a later subform is analyzed. This is what makes multi-form -e with a macro work.

Seed is byte-identical (no source references eval), so no re-mint; bootstrap-test
still passes. Zero-Janet corpus 2534 -> 2544 (eval/load-string cases now run),
0 new divergences; floor raised. Prelude corpus, JVM cert, full Janet gate green.

jolt-r8ku

host/chez/compile-eval.ss

@@ -54,17 +54,97 @@
                        (if (pair? (cdr items)) (cddr items) '())))
             (else (for-each (lambda (x) (ce-scan-requires! x ns)) items))))))))
 
-;; Source string -> Scheme source string (read -> analyze -> emit, all on Chez).
+;; Already-read FORM -> Scheme source string (analyze -> emit on Chez).
 ;; `ns` is the compile namespace unqualified symbols resolve against.
-(define (jolt-analyze-emit src ns)
-  (let* ((form (jolt-ce-read src)))
-    (ce-scan-requires! form ns)
-    (let* ((ctx (make-analyze-ctx ns))
-           (ir (jolt-ce-analyze ctx form)))
-      (jolt-ce-emit ir))))
+(define (jolt-analyze-emit-form form ns)
+  (ce-scan-requires! form ns)
+  (let* ((ctx (make-analyze-ctx ns))
+         (ir (jolt-ce-analyze ctx form)))
+    (jolt-ce-emit ir)))
 
-;; Source string -> value (compile on Chez, then eval the emitted Scheme in the
+;; Source string -> Scheme source string (read then analyze -> emit, all on Chez).
+(define (jolt-analyze-emit src ns)
+  (jolt-analyze-emit-form (jolt-ce-read src) ns))
+
+;; --- runtime defmacro (jolt-r8ku) -------------------------------------------
+;; Shared with emit-image.ss (loaded after this). A defmacro lowers to a def of
+;; its expander fn + a macro flag, exactly as the prelude emits build-time macros.
+
+;; Is `f` a (defmacro ...) / (definline ...) form?
+(define (ce-macro-form? f)
+  (and (cseq? f) (cseq-list? f)
+       (let ((items (seq->list f)))
+         (and (pair? items) (symbol-t? (car items))
+              (let ((h (symbol-t-name (car items))))
+                (or (string=? h "defmacro") (string=? h "definline")))))))
+
+;; (defmacro NAME [docstring] [attr-map] params body...) -> (values "NAME" (fn ...)).
+;; Strips a leading docstring (native string) + attr-map (a non-symbol pmap), then
+;; re-heads the rest with `fn` so a destructured macro arglist desugars. Emits the
+;; BARE fn (the caller wraps it in def-var! + mark-macro!), never a (def NAME ...) —
+;; interning NAME would make require skip the real macro (jolt-r9lm).
+(define (ce-defmacro->fn f)
+  (let* ((items (seq->list f))
+         (name-sym (cadr items))
+         (after-name (cddr items))
+         (a1 (if (and (pair? after-name) (string? (car after-name)))
+                 (cdr after-name) after-name))
+         (after-meta (if (and (pair? a1) (pmap? (car a1)))
+                         (cdr a1) a1))
+         (fn-sym (jolt-symbol #f "fn")))
+    (values (symbol-t-name name-sym)
+            (apply jolt-list (cons fn-sym after-meta)))))
+
+;; A bare top-level (do ...) form — head is the unqualified `do` symbol.
+(define (ce-top-do? form)
+  (and (cseq? form) (cseq-list? form)
+       (let ((h (seq-first form)))
+         (and (symbol-t? h) (jolt-nil? (hc-sym-ns h))
+              (string=? (symbol-t-name h) "do")))))
+
+;; Compile + eval ONE already-read form in compile ns `ns`; returns the value.
+;; A top-level (do ...) is UNROLLED — each subform compiled+eval'd in turn, like
+;; Clojure's top-level do — so a runtime defmacro/def in an earlier subform is
+;; visible (macro flag set, var interned) before a later subform is analyzed.
+(define (jolt-compile-eval-form form ns)
+  (cond
+    ((ce-top-do? form)
+     (let loop ((fs (cdr (seq->list form))) (result jolt-nil))
+       (if (null? fs)
+           result
+           (loop (cdr fs) (jolt-compile-eval-form (car fs) ns)))))
+    ;; runtime defmacro: def the expander fn + mark the var a macro so subsequent
+    ;; forms expand it (hc-macro? reads var-macro-table). Mirrors emit-image.ss
+    ;; ei-emit-ns and the Janet seed eval-defmacro.
+    ((ce-macro-form? form)
+     (let-values (((nm fn-form) (ce-defmacro->fn form)))
+       (def-var! ns nm (jolt-compile-eval-form fn-form ns))
+       (mark-macro! ns nm)
+       jolt-nil))
+    (else
+     (eval (read (open-input-string (jolt-analyze-emit-form form ns)))
+           (interaction-environment)))))
+
+;; Source string -> value (read one form, compile + eval on Chez, in the
 ;; top-level environment where rt.ss's runtime procedures live).
 (define (jolt-compile-eval src ns)
-  (eval (read (open-input-string (jolt-analyze-emit src ns)))
-        (interaction-environment)))
+  (jolt-compile-eval-form (jolt-ce-read src) ns))
+
+;; clojure.core/load-string: read every form from the source string and compile+
+;; eval each in the current ns, returning the last value (nil for blank input).
+;; Mirrors src/jolt/api.janet load-string (the parse-next loop). jolt-r8ku.
+(define (jolt-load-string s)
+  (let loop ((src s) (result jolt-nil))
+    (let ((pn (jolt-parse-next src)))
+      (if (jolt-nil? pn)
+          result
+          (loop (jolt-nth pn 1)
+                (jolt-compile-eval-form (jolt-nth pn 0) (chez-current-ns)))))))
+
+;; eval / load-string are FUNCTIONS on the spine (the compiler image is resident
+;; at runtime). eval takes an already-read FORM (e.g. from quote / list); it and
+;; load-string compile+eval in the current ns. eval is removed from the analyzer's
+;; special-symbol lists (host-contract.ss) so it resolves as an ordinary core var.
+(def-var! "clojure.core" "eval"
+  (lambda (form) (jolt-compile-eval-form form (chez-current-ns))))
+(def-var! "clojure.core" "load-string" jolt-load-string)

host/chez/emit-image.ss

@@ -30,31 +30,8 @@
          (and (pair? items) (symbol-t? (car items))
               (string=? (symbol-t-name (car items)) "ns")))))
 
-;; Is `f` a (defmacro ...) / (definline ...) form?
-(define (ei-macro-form? f)
-  (and (cseq? f) (cseq-list? f)
-       (let ((items (seq->list f)))
-         (and (pair? items) (symbol-t? (car items))
-              (let ((h (symbol-t-name (car items))))
-                (or (string=? h "defmacro") (string=? h "definline")))))))
-
-;; (defmacro NAME [docstring] [attr-map] params body...) -> (values "NAME" (fn ...)).
-;; Mirrors driver.janet defmacro->fn: strip a leading docstring (native string) and
-;; an attr-map (a pmap that isn't a symbol), then re-head the rest with `fn` so a
-;; destructured macro arglist desugars before lowering. We emit the BARE fn (the
-;; caller wraps it in def-var! + mark-macro!), never a (def NAME ...) — interning
-;; NAME would make require skip the real macro (jolt-r9lm).
-(define (ei-defmacro->fn f)
-  (let* ((items (seq->list f))
-         (name-sym (cadr items))
-         (after-name (cddr items))
-         (a1 (if (and (pair? after-name) (string? (car after-name)))
-                 (cdr after-name) after-name))
-         (after-meta (if (and (pair? a1) (pmap? (car a1)))
-                         (cdr a1) a1))
-         (fn-sym (jolt-symbol #f "fn")))
-    (values (symbol-t-name name-sym)
-            (apply jolt-list (cons fn-sym after-meta)))))
+;; ei-macro-form? / ei-defmacro->fn moved to compile-eval.ss (ce-macro-form? /
+;; ce-defmacro->fn, loaded before this) — shared with the runtime defmacro spine.
 
 ;; Cross-compile one namespace's source to a list of guard-wrapped Scheme strings.
 ;; Mirrors driver.janet emit-ns-forms-list/emit-core-prelude + emit-form-scheme.
@@ -70,8 +47,8 @@
           (ce-scan-requires! f ns-name)
           (cond
             ((ei-ns-form? f) (loop (cdr forms) acc))
-            ((ei-macro-form? f)
-             (let-values (((nm fn-form) (ei-defmacro->fn f)))
+            ((ce-macro-form? f)
+             (let-values (((nm fn-form) (ce-defmacro->fn f)))
                (let ((scm (guard (e (#t #f))
                             (let ((ctx (make-analyze-ctx ns-name)))
                               (jolt-ce-emit (jolt-ce-analyze ctx fn-form))))))

host/chez/host-contract.ss

@@ -105,9 +105,12 @@
 ;; --- special forms ----------------------------------------------------------
 ;; Mirrors host_iface special-names + interop-head? — forms the analyzer marks
 ;; uncompilable (the handled specials are dispatched in analyze-list BEFORE this).
+;; `eval` is NOT here: it is a clojure.core FUNCTION on the spine (compile-eval.ss
+;; def-var!s it), so it must resolve as an ordinary var, not punt (jolt-r8ku).
+;; `defmacro` stays special — the spine intercepts it before analysis.
 (define hc-special-names
   '("quote" "syntax-quote" "unquote" "unquote-splicing" "do" "if" "def"
-    "defmacro" "fn*" "let*" "loop*" "recur" "throw" "try" "set!" "eval" "new"
+    "defmacro" "fn*" "let*" "loop*" "recur" "throw" "try" "set!" "new"
     "." "gen-class" "monitor-enter" "monitor-exit" "letfn"))
 (define (hc-interop-head? name)
   (let ((n (string-length name)))
@@ -180,7 +183,7 @@
 ;; clojure.core / the compile ns; a foo# auto-gensym is stable within one `.
 (define hc-special-symbols
   '("quote" "syntax-quote" "unquote" "unquote-splicing" "do" "if" "def"
-    "defmacro" "fn*" "let*" "loop*" "recur" "throw" "try" "set!" "var" "eval"
+    "defmacro" "fn*" "let*" "loop*" "recur" "throw" "try" "set!" "var"
     "new" "."))
 (define (hc-special-symbol? nm) (and (member nm hc-special-symbols) #t))