diff --git a/Source/DOH/base.c b/Source/DOH/base.c
index ac1b33666..c17f32824 100644
--- a/Source/DOH/base.c
+++ b/Source/DOH/base.c
@@ -829,3 +829,28 @@ DohGetmark(DOH *ho) {
   DohBase *h = (DohBase *) ho;
   return h->flag_usermark;
 }
+
+/* -----------------------------------------------------------------------------
+ * DohCall()
+ *
+ * Invokes a function via DOH.  A Function is represented by a hash table with
+ * the following attributes:
+ *
+ *       "builtin"    -  Pointer to built-in function (if any)
+ *
+ * (Additional attributes may be added later)
+ * 
+ * Returns a DOH object with result on success. Returns NULL on error
+ * ----------------------------------------------------------------------------- */
+
+DOH *
+DohCall(DOH *func, DOH *args) {
+  DOH *result;
+  DOH *(*builtin)(DOH *);
+
+  builtin = (DOH *(*)(DOH *)) GetVoid(func,"builtin");
+  if (!builtin) return 0;
+  result = (*builtin)(args);
+  return result;
+}
+
diff --git a/Source/DOH/doh.h b/Source/DOH/doh.h
index 4c22739d8..b807a4bd5 100644
--- a/Source/DOH/doh.h
+++ b/Source/DOH/doh.h
@@ -104,7 +104,7 @@
 #define DohNewVoid         DOH_NAMESPACE(NewVoid)
 #define DohSplit           DOH_NAMESPACE(Split)
 #define DohNone            DOH_NAMESPACE(None)
-
+#define DohCall            DOH_NAMESPACE(Call)
 #define DohObjMalloc       DOH_NAMESPACE(ObjMalloc)
 #define DohObjFree         DOH_NAMESPACE(ObjFree)
 #define DohMemoryDebug     DOH_NAMESPACE(MemoryDebug)
@@ -377,6 +377,7 @@ extern void      DohMemoryDebug(void);
 #define Setmark            DohSetmark
 #define Getmark            DohGetmark
 #define None               DohNone
+#define Call               DohCall
 #endif
 
 #ifdef NIL
diff --git a/Source/DOH/fio.c b/Source/DOH/fio.c
index db7e5eb1c..d42be5fa4 100644
--- a/Source/DOH/fio.c
+++ b/Source/DOH/fio.c
@@ -123,7 +123,7 @@ DohvPrintf(DOH *so, const char *format, va_list ap)
       }
       break;
     case 10: /* Look for a width and precision */
-      if (isdigit(*p) && (*p != '0')) {
+      if (isdigit((int)*p) && (*p != '0')) {
 	w = temp;
 	*(w++) = *p;
 	*(fmt++) = *p;
@@ -154,7 +154,7 @@ DohvPrintf(DOH *so, const char *format, va_list ap)
       break;
       
     case 20: /* Hmmm. At the start of a width field */
-      if (isdigit(*p)) {
+      if (isdigit((int)*p)) {
 	*(w++) = *p;
 	*(fmt++) = *p;
       } else if (strchr(fmt_codes,*p)) {
@@ -196,7 +196,7 @@ DohvPrintf(DOH *so, const char *format, va_list ap)
 
     case 40:
       /* Start of precision expected */
-      if (isdigit(*p) && (*p != '0')) {
+      if (isdigit((int)*p) && (*p != '0')) {
 	*(fmt++) = *p;
 	*(w++) = *p;
 	state = 41;
@@ -217,7 +217,7 @@ DohvPrintf(DOH *so, const char *format, va_list ap)
       }
       break;
     case 41:
-      if (isdigit(*p)) {
+      if (isdigit((int)*p)) {
 	*(fmt++) = *p;
 	*(w++) = *p;
       } else if (strchr(fmt_codes,*p)) {
diff --git a/Source/DOH/string.c b/Source/DOH/string.c
index d48b82ca4..7b87acbfe 100644
--- a/Source/DOH/string.c
+++ b/Source/DOH/string.c
@@ -529,11 +529,11 @@ match_identifier(char *base, char *s, char *token, int tokenlen)
   while (s) {
     s = strstr(s,token);
     if (!s) return 0;
-    if ((s > base) && (isalnum(*(s-1)) || (*(s-1) == '_'))) {
+    if ((s > base) && (isalnum((int) *(s-1)) || (*(s-1) == '_'))) {
       s += tokenlen;
       continue;
     }
-    if (isalnum(*(s+tokenlen)) || (*(s+tokenlen) == '_')) {
+    if (isalnum((int)*(s+tokenlen)) || (*(s+tokenlen) == '_')) {
       s += tokenlen;
       continue;
     }
@@ -549,7 +549,7 @@ match_identifier_begin(char *base, char *s, char *token, int tokenlen)
   while (s) {
     s = strstr(s,token);
     if (!s) return 0;
-    if ((s > base) && (isalnum(*(s-1)) || (*(s-1) == '_'))) {
+    if ((s > base) && (isalnum((int)*(s-1)) || (*(s-1) == '_'))) {
       s += tokenlen;
       continue;
     }
@@ -564,7 +564,7 @@ match_identifier_end(char *base, char *s, char *token, int tokenlen)
   while (s) {
     s = strstr(s,token);
     if (!s) return 0;
-    if (isalnum(*(s+tokenlen)) || (*(s+tokenlen) == '_')) {
+    if (isalnum((int)*(s+tokenlen)) || (*(s+tokenlen) == '_')) {
       s += tokenlen;
       continue;
     }
@@ -819,7 +819,7 @@ String_chop(DOH *so)
   String *str = (String *) ObjData(so);
   /* Replace trailing whitespace */
   c = str->str + str->len - 1;
-  while ((str->len > 0) && (isspace(*c))) {
+  while ((str->len > 0) && (isspace((int)*c))) {
     if (str->sp >= str->len) {
       str->sp--;
       if (*c == '\n') str->line--;