public override SValue Evaluate(ExecEnvironment env)
{
SValue v = varValue.Evaluate(env);
SValue ret = v;
if (!makeImmutable && v.Immutable)
{
ret = v.Clone();
ret.Immutable = false;
}
if (makeImmutable)
{
ret.Immutable = true;
}
ret.RefDict = null;
ret.RefList = null;
if (env.ContainsKey(varName) && env[varName].Immutable)
{
throw new VMException(varName + ": variable is immutable", headAtom);
}
env.NewVar(varName, ret);
return(ret);
}
public override SValue Evaluate(ExecEnvironment env)
{
SValue v = varValue.Evaluate(env);
SValue ret = v;
if (!makeImmutable && v.Immutable)
{
ret = v.Clone();
ret.Immutable = false;
}
if (makeImmutable)
{
ret.Immutable = true;
}
ret.RefDict = null;
ret.RefList = null;
if (nameExpr == null)
{
if (env.ContainsKey(varName) && env[varName].Immutable)
{
throw new VMException(varName + ": variable is immutable", headAtom);
}
if (makeImmutable)
{
env.NewVar(varName, ret);
}
else
{
env[varName] = ret;
}
}
else
{
var n = nameExpr.Evaluate(env);
if (n.RefDict?.Immutable == true || n.RefList?.Immutable == true)
{
throw new VMException(varName + ": variable is immutable", headAtom);
}
if (n.RefDict != null)
{
n.RefDict.Get <Dictionary <string, SValue> >()[n.RefDictKey] = ret;
}
else if (n.RefList != null)
{
n.RefList.Get <List <SValue> >()[n.RefListIndex] = ret;
}
else
{
throw new VMException("invalid variable setting", headAtom);
}
}
return(ret);
}