public void Initialize()
{
foreach (var v in modSet)
{
varDefs[v] = Expr.Ident(v);
}
foreach (var cmd in cmds)
{
if (cmd.Item2 == null)
{
varDefs[cmd.Item1] = null;
}
else
{
var s = new SubstitutionDuplicator(varDefs);
var r = (Expr)s.Visit(cmd.Item2);
varDefs[cmd.Item1] = s.isSubstitutable ? r : null;
}
}
}
void UpdateAssignment(Variable variable, Expr rhs, Dictionary <Variable, Expr> newVarDefs)
{
if ((varDefs.ContainsKey(variable) && varDefs[variable] == null) ||
rhs == null)
{
newVarDefs[variable] = null;
return;
}
var s = new SubstitutionDuplicator(newVarDefs);
var r = (Expr)s.Visit(rhs);
if (s.isSubstitutable)
{
newVarDefs[variable] = r;
}
else
{
newVarDefs[variable] = null;
}
}