/// <summary>
/// Compiles the sub routine.
/// </summary>
/// <param name="parentElement">The parent element.</param>
private void CompileSubRoutine(XElement parentElement)
{
// seems that labels only need to be unique inside functions / methods
this.whileStatementCount = -1;
this.ifStatementCount = -1;
string subroutineName = string.Empty;
this.symbolTable.StartNewSubroutine();
XElement subRoutineElement = new XElement("subroutineDec");
parentElement.Add(subRoutineElement);
bool isConstructor = false;
bool isMethod = false;
// while not the opening bracked of the method/constructor/function params
while (this.classTokens.Peek().Value2 != "(")
{
Pair <string, string> token = this.classTokens.Pop();
if (isConstructor == false)
{
isConstructor = token.Value2 == "constructor";
}
if (isMethod == false)
{
isMethod = token.Value2 == "method";
}
// finds method name i.e. if the next token is an opening bracket
// we must be on the method name
if (this.classTokens.Peek().Value2 == "(")
{
subroutineName = token.Value2;
// see page 238 - don't bother adding method or class names to symbol table
subRoutineElement.Add(new XElement(token.Value1, token.Value2,
new XAttribute("category", "Subroutine")));
}
else
{
subRoutineElement.Add(new XElement(token.Value1, token.Value2));
}
}
// add the opening braket of param list
this.CompileTerminal();
// add the param list
this.CompileParameterList(isMethod);
// add closing bracket of params
this.CompileTerminal();
// add opening curley of methodBody
this.CompileTerminal();
// compile sub routine var declarations (they're always first);
this.CompileSubRoutineVariableDeclarations();
int numberOfLocals = symbolTable.VarCount(Kind.Var);
this.vmWriter.WriteFunction(this.className + "." + subroutineName, symbolTable.VarCount(Kind.Var));
if (isConstructor)
{
this.vmWriter.WritePush(Segment.Constant, this.symbolTable.VarCount(Kind.Field));
this.vmWriter.WriteCall("Memory.alloc", 1);
this.vmWriter.WritePop(Segment.Pointer, 0);
}
else if (isMethod)
{
this.vmWriter.WritePush(Segment.Argument, 0);
this.vmWriter.WritePop(Segment.Pointer, 0);
}
this.CompileSubroutineStatments();
// compile closing curley
this.CompileTerminal();
}
