Render an expr if expr_t::text() has no string

src/expr.cc

@@ -78,6 +78,16 @@ expr_t::ptr_op_t expr_t::get_op() throw()
   return ptr;
 }
 
+string expr_t::text()
+{
+  if (str.empty()) {
+    std::ostringstream out;
+    ptr->print(out);
+    set_text(out.str());
+  }
+  return str;
+}
+
 expr_t& expr_t::operator=(const expr_t& _expr)
 {
   if (this != &_expr) {

src/expr.h

@@ -116,10 +116,7 @@ public:
   }
 
   ptr_op_t get_op() throw();
-
-  string text() const throw() {
-    return str;
-  }
+  string   text();
 
   // This has special use in the textual parser
   void set_text(const string& txt) {