--- a/src/tokenizer.cpp	Thu May 22 20:39:52 2008 -0700
+++ b/src/tokenizer.cpp	Thu Jun 12 17:51:33 2008 -0700
@@ -287,7 +287,7 @@
 };
 
 
-TOKEN::TOKEN(char *fn, string_set *includes) {
+TOKEN::TOKEN(const char *fn, string_set *includes) {
     pushed = false;
     include_files = includes;
     include(fn);
@@ -301,7 +301,7 @@
 
 void TOKEN::pop() {
     ifstream *is = streams.front();
-    char *fn = filenames.front();
+    const char *fn = filenames.front();
     streams.pop_front();
     filenamess.erase(fn);
     if (filenames.size() > 1)   filenames.pop_front();
@@ -339,7 +339,7 @@
 }
 
 
-bool TOKEN::include(char *fn) {
+bool TOKEN::include(const char *fn) {
     string_set::iterator i = filenamess.find(fn);
     if (i != filenamess.end()) {
         token_error("redundant or recursive include file detected");
@@ -363,9 +363,9 @@
 }
 
 
-char *TOKEN::next() {
+const char *TOKEN::next() {
     if (!pending_tokens.empty()) {
-        char *t = pending_tokens.front();
+        const char *t = pending_tokens.front();
         pending_tokens.pop_front();
         return t;
     }
@@ -445,10 +445,10 @@
 
     buffer[count] = '\0';
     if (count == 0) return NULL;
-    char *t = register_string((char*)buffer);
+    const char *t = register_string((char*)buffer);
     if (t == token_include) {
-        char *f = next();   // should be file name
-        char *s = next();   // should be semicolon
+        const char *f = next();   // should be file name
+        const char *s = next();   // should be semicolon
         if (s == token_semi) {
             include(f);
             return next();
@@ -464,7 +464,7 @@
 
 
 int TOKEN::nextint() {
-    char *t = next();
+    const char *t = next();
     char *e;
     long i = strtol(t, &e, 10);
     if (*e != '\0') {
@@ -516,10 +516,10 @@
 void TOKEN::token_error() {
     token_error("syntax error at line %d in file %s -- ", cur_line(), cur_fn());
     line_list::iterator   j = linenumbers.begin();
-    string_list::iterator i = filenames.begin();
+    string_list::const_iterator i = filenames.begin();
     for (; i!=filenames.end(); i++,j++) {
         if (i != filenames.begin()) {
-            char *fn = (*i);
+            const char *fn = (*i);
             int   li = (*j);
             token_error("    included from line %d in file %s -- ", li, fn);
         }