public override void Visit(AST_kary node)
{
printTag(node);
f.WriteLine();
int arity = node.NumChildren;
indent++;
for (int i = 0; i < arity; i++)
{
AST ch = node[i];
if (ch != null)
{
ch.Accept(this);
}
else
{
f.WriteLine("{0}-- missing child --", indentString(indent));
}
}
if (arity == 0)
{
f.WriteLine("{0}-- no children --", indentString(indent));
}
indent--;
}
public override void Visit(AST_kary node)
{
printTag(node);
f.WriteLine();
int arity = node.NumChildren;
indent++;
for( int i = 0; i < arity; i++ ) {
AST ch = node[i];
if (ch != null)
ch.Accept(this);
else
f.WriteLine("{0}-- missing child --", indentString(indent));
}
if (arity == 0)
f.WriteLine("{0}-- no children --", indentString(indent));
indent--;
}
public override void Visit(AST_kary node)
{
int children = node.NumChildren;
switch(node.Tag) {
case NodeType.UsingList:
for (int i = 0; i < children; i++)
{
if (((AST_leaf)node[i]).Sval != "CbRuntime")
ReportError(node[0].LineNumber, "Invalid using identifier: '{0}' (only allowed identifier is CbRuntime)", ((AST_leaf)node[i]).Sval);
}
break;
case NodeType.DeclList:
for (int i = 0; i < children; i++)
{
node[i].Accept(this);
}
break;
case NodeType.FieldList:
// already handled by prePass
break;
case NodeType.IdList:
// already handled in NodeType.LocalDecl
break;
case NodeType.Formals:
// visit all statements
for (int i = 0; i < children; i++)
node[i].Accept(this);
break;
case NodeType.Block:
// change scope
localSymbols.Enter();
// accept all statements
for (int i = 0; i < children; i++)
{
node[i].Accept(this);
}
// change scope
localSymbols.Exit();
break;
case NodeType.Actuals:
node.Type = CbType.Void;
// visit all parameters
for (int i = 0; i < children; i++)
{
node[i].Accept(this);
if (node[i].Type == CbType.Error)
node.Type = CbType.Error;
}
break;
case NodeType.Return:
node.Type = CbType.Void;
if (node.NumChildren > 0)
{
node[0].Accept(this);
node.Type = node[0].Type;
}
break;
default:
throw new Exception("{0} is not a tag compatible with an AST_kary node");
}
}
// Makes two shallow passes over the declarations inside a class to obtain
// the names and types of all consts, methods and structs declared at the
// top level; without this info, typechecking cannot begin.
private void prePass(AST node)
{
addPredeclared();
AST_kary decls = node as AST_kary;
if (decls == null || decls.Tag != NodeType.DeclList)
{
throw new Exception("Bad argument passed to prePass");
}
// make one pass over the declarations just to enter the names of structs into
// the Structs table
int arity = decls.NumChildren;
for (int i = 0; i < arity; i++)
{
AST ch = decls[i];
if (ch.Tag != NodeType.Struct)
{
continue; // it was not a struct declaration
}
string name = ((AST_leaf)(ch[0])).Sval;
if (Structs.ContainsKey(name))
{
ReportError(ch[0].LineNumber, "Duplicate declaration of struct {0}", name);
}
else
{
Structs.Add(name, new CbStruct(name));
}
}
// now make a second pass over the declarations to
// 1. add const declarations to the Consts table
// 2. add method declarations to the Methods table
// 3. fill in the field details for each struct in the Structs table
for (int i = 0; i < arity; i++)
{
AST ch = decls[i];
string name;
CbType typ;
int argsize;
switch (ch.Tag)
{
case NodeType.Struct:
CbStruct str;
name = ((AST_leaf)(ch[0])).Sval;
// find existing struct
Structs.TryGetValue(name, out str); // do error checking
AST fldlst = ch[1];
AST fld;
AST idlst;
argsize = fldlst.NumChildren;
int idsize;
// iterate through the field list
for (int j = 0; j < argsize; j++)
{
// get field declaration
fld = fldlst[j];
// find declaration type
typ = lookUpType(fld[0]);
// get list of variables declared
idlst = fld[1];
idsize = idlst.NumChildren;
// add all declared variables to the struct
for (int k = 0; k < idsize; k++)
{
str.AddField(((AST_leaf)(idlst[k])).Sval, typ);
}
}
break;
case NodeType.Const:
// Add the name and type of this constant to the Consts table
name = ((AST_leaf)(ch[1])).Sval;
typ = lookUpType(ch[0]);
if (Consts.ContainsKey(name))
{
ReportError(ch[0].LineNumber, "Duplicate declaration of const {0}", name);
}
else
{
Consts.Add(name, typ);
}
break;
case NodeType.Method:
name = ((AST_leaf)(ch[1])).Sval;
ch[2].Accept(this);
// check for duplicate method
CbMethod existing = getMethod(name, ch[2], false);
if (existing != null)
{
ReportError(ch[0].LineNumber, "Duplicate declaration of method {0}", name);
break;
}
CbType typm = CbType.Void;
// create new CbMethod
if (ch[0] != null)
{
typm = lookUpType(ch[0]);
}
CbMethod method = new CbMethod(name, typm);
// add argument list (full signature) to CbMethod
AST args = ch[2];
for (int j = 0; j < args.NumChildren; j++)
{
method.ArgType.Add(lookUpType(args[j][0]));
}
// get list of overloaded methods sharing same name
List <CbMethod> methods;
if (!Methods.TryGetValue(name, out methods)) // if none exist create new list
{
methods = new List <CbMethod>();
}
// add method to list
methods.Add(method);
// replace old list of methods with this name with new list
Methods[name] = methods;
break;
default:
throw new Exception("Unexpected node type " + ch.Tag);
}
}
}
public override void Visit(AST_kary node)
{
int children = node.NumChildren;
switch (node.Tag)
{
case NodeType.UsingList:
for (int i = 0; i < children; i++)
{
if (((AST_leaf)node[i]).Sval != "CbRuntime")
{
ReportError(node[0].LineNumber, "Invalid using identifier: '{0}' (only allowed identifier is CbRuntime)", ((AST_leaf)node[i]).Sval);
}
}
break;
case NodeType.DeclList:
for (int i = 0; i < children; i++)
{
node[i].Accept(this);
}
break;
case NodeType.FieldList:
// already handled by prePass
break;
case NodeType.IdList:
// already handled in NodeType.LocalDecl
break;
case NodeType.Formals:
// visit all statements
for (int i = 0; i < children; i++)
{
node[i].Accept(this);
}
break;
case NodeType.Block:
// change scope
localSymbols.Enter();
// accept all statements
for (int i = 0; i < children; i++)
{
node[i].Accept(this);
}
// change scope
localSymbols.Exit();
break;
case NodeType.Actuals:
node.Type = CbType.Void;
// visit all parameters
for (int i = 0; i < children; i++)
{
node[i].Accept(this);
if (node[i].Type == CbType.Error)
{
node.Type = CbType.Error;
}
}
break;
case NodeType.Return:
node.Type = CbType.Void;
if (node.NumChildren > 0)
{
node[0].Accept(this);
node.Type = node[0].Type;
}
break;
default:
throw new Exception("{0} is not a tag compatible with an AST_kary node");
}
}
public virtual void Visit(AST_kary n)
{
Console.WriteLine("Internal compiler error! This method should have been overridden");
}
public virtual void Visit(AST_kary n)
{
Console.WriteLine("Internal compiler error! This method should have been overridden");
}