introduce make_boolean_expr

This is a type-safe drop-in replacement for exprt::make_bool(value).

Author: kroening

src/util/expr_util.cpp

@@ -281,3 +281,11 @@ bool is_constantt::is_constant_address_of(const exprt &expr) const
 
   return false;
 }
+
+constant_exprt make_boolean_expr(bool value)
+{
+  if(value)
+    return true_exprt();
+  else
+    return false_exprt();
+}

src/util/expr_util.h

@@ -21,6 +21,7 @@ Author: Daniel Kroening, kroening@kroening.com
 
 #include <functional>
 
+class constant_exprt;
 class exprt;
 class symbol_exprt;
 class update_exprt;
@@ -96,4 +97,7 @@ class is_constantt
   virtual bool is_constant_address_of(const exprt &) const;
 };
 
+/// returns true_exprt if given true and false_exprt otherwise
+constant_exprt make_boolean_expr(bool);
+
 #endif // CPROVER_UTIL_EXPR_UTIL_H