--- a
+++ b/src/include/function/ScalarLogDensity.h
@@ -0,0 +1,24 @@
+#ifndef SCALAR_LOG_DENSITY_H_
+#define SCALAR_LOG_DENSITY_H_
+
+#include <function/ScalarFunction.h>
+
+namespace jags {
+
+    class ScalarDist;
+
+    /**
+     * @short Log density function for a scalar-valued Distribution
+     */
+    class ScalarLogDensity : public ScalarFunction
+    {
+	ScalarDist const *_dist;
+    public:
+	ScalarLogDensity(ScalarDist const *dist);
+	bool checkParameterValue(std::vector<double const *> const &args) const;
+	double evaluate(std::vector <double const *> const &args) const;
+    };
+
+}
+
+#endif /* SCALAR_LOG_DENSITY_H_ */