Add some debug prints to the C side

src/event.c

@@ -5,6 +5,8 @@
  * functions to lookup and execute events.
  */
 
+#include <stdarg.h>
+
 #include "unroff.h"
 
 #define NUM_VEC_EVENTS   6
@@ -42,6 +44,28 @@ static char *event_names[] = {
     "character event",
 };
 
+int debug_flag = 0;
+
+void debug_printf(const char *format, ...) {
+    va_list ap;
+
+    if (!debug_flag) return;
+    va_start(ap, format);
+    vfprintf(stderr, format, ap);
+    va_end(ap);
+}
+
+void debug_string(const char *bytes, int nbytes) {
+    char *string;
+
+    if (!debug_flag) return;
+    string = safe_malloc(nbytes + 1);
+    memcpy(string, bytes, nbytes);
+    string[nbytes] = '\0';
+    debug_printf("%s", string);
+    free(string);
+}
+
 static Object make_event_object(Object x) {
     switch (TYPE(x)) {
     case T_Null:
@@ -64,6 +88,9 @@ static Object store_event(Table *tp, char *key, int size, Object obj,
     Elem *oldp;
     Object ret = False;
 
+    debug_printf("store_event ");
+    debug_string(key, size);
+    debug_printf("\n");
     if ((oldp = table_lookup(tp, key, size)) != 0)
 	ret = get_object(oldp->obj);
     if (!Nullp(obj)) {
@@ -184,9 +211,35 @@ Object p_chardef(Object key) {
     return def_char_event(chars, key, Null);
 }
 
+const char *event_name(Event e) {
+    switch (e) {
+#define ENAME(x) case x: return #x;
+        ENAME(EV_REQUEST);
+        ENAME(EV_MACRO);
+        ENAME(EV_STRING);
+        ENAME(EV_NUMREG);
+        ENAME(EV_SPECIAL);
+        ENAME(EV_ESCAPE);
+        ENAME(EV_CHAR);
+        ENAME(EV_EQUATION);
+        ENAME(EV_SENTENCE);
+        ENAME(EV_LINE);
+        ENAME(EV_PROLOG);
+        ENAME(EV_EPILOG);
+        ENAME(EV_OPTION);
+        ENAME(EV_START);
+        ENAME(EV_EXIT);
+#undef ENAME
+    }
+    return "???";
+}
+
 Elem *event_lookup(Event e, char *key, int size) {
     Elem *p;
 
+    debug_printf("event_lookup %s ", event_name(e));
+    debug_string(key, size);
+    debug_printf("\n");
     if (key && size == 0) {
 	switch(e) {
 	case EV_REQUEST: