fix: make print variadic to match println behavior

print was registered as a unary function (single argument), while
println was variadic. This meant (print "%" expr) only received "%"
as its argument — the second expression was evaluated separately.

Changed print from register_unary to register_vary with the same
format-string interpolation and multi-arg spacing as println, just
without the trailing newline. Moved implementation from system.c to
builtins.c alongside println/show to share fmt_interpolate.

Author: singaraiona

src/lang/eval.c

@@ -2038,7 +2038,7 @@ static void ray_register_builtins(void) {
     /* Eval, parse, print, meta */
     register_unary("eval",       RAY_FN_NONE, ray_eval_builtin_fn);
     register_unary("parse",      RAY_FN_NONE, ray_parse_builtin_fn);
-    register_unary("print",      RAY_FN_NONE, ray_print_fn);
+    register_vary("print",       RAY_FN_NONE, ray_print_fn);
     register_unary("meta",       RAY_FN_NONE, ray_meta_fn);
 
     /* System builtins */

src/lang/internal.h

@@ -410,7 +410,7 @@ void   ray_dl_reset_rules(void);
 /* System builtins (formerly static in eval.c, now in system.c) */
 ray_t* ray_eval_builtin_fn(ray_t* x);
 ray_t* ray_parse_builtin_fn(ray_t* x);
-ray_t* ray_print_fn(ray_t* x);
+ray_t* ray_print_fn(ray_t** args, int64_t n);
 ray_t* ray_meta_fn(ray_t* x);
 ray_t* ray_gc_fn(ray_t* x);
 ray_t* ray_system_fn(ray_t* x);

src/ops/builtins.c

@@ -242,6 +242,33 @@ ray_t* ray_println_fn(ray_t** args, int64_t n) {
     return RAY_NULL_OBJ;
 }
 
+/* (print val1 val2 ...) — like println but without trailing newline */
+ray_t* ray_print_fn(ray_t** args, int64_t n) {
+    for (int64_t i = 0; i < n; i++)
+        if (ray_is_lazy(args[i])) args[i] = ray_lazy_materialize(args[i]);
+
+    /* Format string mode: first arg is a string with % placeholders */
+    if (n >= 2 && args[0] && args[0]->type == -RAY_STR) {
+        const char* fmt = ray_str_ptr(args[0]);
+        size_t flen = ray_str_len(args[0]);
+        size_t out_len = 0;
+        char* result = fmt_interpolate(fmt, flen, args, n, 1, &out_len);
+        if (result) {
+            fwrite(result, 1, out_len, stdout);
+            fflush(stdout);
+            ray_sys_free(result);
+            return RAY_NULL_OBJ;
+        }
+    }
+
+    for (int64_t i = 0; i < n; i++) {
+        if (i > 0) fputc(' ', stdout);
+        ray_lang_print(stdout, args[i]);
+    }
+    fflush(stdout);
+    return RAY_NULL_OBJ;
+}
+
 /* (show val1 val2 ...) — print values to stdout using ray_fmt, newline at end */
 ray_t* ray_show_fn(ray_t** args, int64_t n) {
     for (int64_t i = 0; i < n; i++) {

src/ops/system.c

@@ -169,11 +169,7 @@ ray_t* ray_parse_builtin_fn(ray_t* x) {
 }
 
 /* (print val) -- print without newline, return the value */
-ray_t* ray_print_fn(ray_t* x) {
-    ray_fmt_print(stdout, x, 0);
-    fflush(stdout);
-    return x;
-}
+/* print moved to builtins.c alongside println/show */
 
 /* (meta x) -- return metadata about an object as a dict */
 ray_t* ray_meta_fn(ray_t* x) {