static void Designator(out DesType des)
{
string name;
int indexType;
Ident(out name);
Entry entry = Table.Find(name);
if (!entry.declared)
{
SemError("undeclared identifier");
}
des = new DesType(entry);
if (entry.kind == Kinds.Var)
{
CodeGen.LoadAddress(entry);
}
if (la.kind == lbrack_Sym)
{
Get();
if (IsArray(des.type))
{
des.type--;
}
else
{
SemError("unexpected subscript");
}
if (des.entry.kind != Kinds.Var)
{
SemError("unexpected subscript");
}
CodeGen.Dereference();
Expression(out indexType);
if (!IsArith(indexType))
{
SemError("invalid subscript type");
}
CodeGen.Index();
Expect(rbrack_Sym);
}
}
static void Factor(out int type)
{
type = Types.noType;
int size;
DesType des;
ConstRec con;
if (la.kind == identifier_Sym)
{
Designator(out des);
type = des.type;
switch (des.entry.kind)
{
case Kinds.Var:
CodeGen.Dereference();
break;
case Kinds.Con:
CodeGen.LoadConstant(des.entry.value);
break;
default:
SemError("wrong kind of identifier");
break;
}
}
else if (StartOf(15))
{
Constant(out con);
type = con.type;
CodeGen.LoadConstant(con.value);
}
else if (la.kind == new_Sym)
{
Get();
BasicType(out type);
type++;
Expect(lbrack_Sym);
Expression(out size);
if (!IsArith(size))
{
SemError("array size must be integer");
}
CodeGen.Allocate();
Expect(rbrack_Sym);
}
else if (la.kind == bang_Sym)
{
Get();
Factor(out type);
if (!IsBool(type))
{
SemError("boolean operand needed");
}
else
{
CodeGen.NegateBoolean();
}
type = Types.boolType;
}
else if (la.kind == lparen_Sym)
{
Get();
Expression(out type);
Expect(rparen_Sym);
}
else
{
SynErr(58);
}
}