ivl_type_s: Add get_scalar() method

Currently only the netvector_t type implements the get_scalar() method. To
check whether a type is scalar it is first cast to netvector_t and then the
method is called.

But there are other types, such as areal that can also be scalar. To
support indicating that a real type is scalar add a virtual get_scalar()
method to ivl_type_s, which is the base class for all types.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>

netlist.cc

@@ -715,10 +715,8 @@ bool NetNet::get_signed() const
 
 bool NetNet::get_scalar() const
 {
-      if (const netvector_t*vec = dynamic_cast<const netvector_t*> (net_type_))
-	    return vec->get_scalar();
-      else
-	    return false;
+      ivl_assert(*this, net_type_);
+      return net_type_->get_scalar();
 }
 
 const netenum_t*NetNet::enumeration(void) const

nettypes.cc

@@ -56,6 +56,11 @@ bool ivl_type_s::get_signed() const
       return false;
 }
 
+bool ivl_type_s::get_scalar() const
+{
+      return false;
+}
+
 bool ivl_type_s::type_compatible(ivl_type_t that) const
 {
       if (this == that)

nettypes.h

@@ -45,6 +45,7 @@ class ivl_type_s {
 	// those specific types.
       virtual ivl_variable_type_t base_type() const;
       virtual bool get_signed() const;
+      virtual bool get_scalar() const;
 
 	// Return true if "that" type is compatible with this
 	// type. Compatible means the types are essentially the same.