public ThreeAddressCode(MethodDefinition method, Triplet root, List <Triplet> rawTriplets, List <VariableDefinition> temporaryVariables)
{
this.method = method;
this.root = root;
this.rawTriplets = rawTriplets;
this.temporaryVariables = temporaryVariables;
}
/// <summary>
/// return ident | digit
/// </summary>
/// <returns><c>true</c> if this instance is return triplet the specified triplet; otherwise, <c>false</c>.</returns>
/// <param name="triplet">Triplet.</param>
bool IsReturnTriplet(out Triplet triplet)
{
triplet = new Triplet(TripletOpCode.Return);
consumeToken();
// Support only return ident
if (Tok().kind == Token.TokenKind.Ident)
{
// FIXME: Here we should keep a list of active variables and the we should use it,
// because this is not a variable definition but a variable reference.
triplet.Operand1 = new VariableDefinition(Tok().data, /*TypeReference*/ null);
return(true);
}
return(false);
}
/// <summary>
/// result = operand1 [operator] [operand2]
/// </summary>
/// <returns><c>true</c> if this instance is assignment triplet the specified triplet; otherwise, <c>false</c>.</returns>
/// <param name="triplet">Triplet.</param>
bool IsAssignmentTriplet(out Triplet triplet)
{
triplet = new Triplet(TripletOpCode.Assignment);
triplet.Result = new VariableDefinition(Tok().data, /*TypeReference*/ null);
consumeToken();
// consume the =
consumeToken();
if (Tok().kind != Token.TokenKind.Ident && Tok().kind != Token.TokenKind.Digit)
{
errors.AppendLine("identifier or digit expected");
return(false);
}
if (Tok().kind == Token.TokenKind.Ident)
{
triplet.Operand1 = new VariableDefinition(Tok().data, /*TypeReference*/ null);
}
else if (Tok().kind == Token.TokenKind.Digit)
{
triplet.Operand1 = Int64.Parse(Tok().data);
}
return(true);
}
/// <summary>
/// The triplets have the form
/// triplet := [label] ident operator ident [operator] [ident]
/// </summary>
/// <returns><c>true</c> if this instance is triplet; otherwise, <c>false</c>.</returns>
bool IsTriplet(out Triplet triplet)
{
triplet = null;
if (Tok().kind != Token.TokenKind.Ident)
{
errors.AppendLine("Triplet must begin with an ident.");
return(false);
}
Token nextTok = lookAhead();
//FIXME: Skip the label for now: L1:
if (nextTok.kind == Token.TokenKind.Colon)
{
consumeToken();
consumeToken();
nextTok = lookAhead();
}
if (Tok().data == "return")
{
IsReturnTriplet(out triplet);
}
else if (nextTok.kind == Token.TokenKind.Equals)
{
IsAssignmentTriplet(out triplet);
}
consumeToken();
if (Tok().kind == Token.TokenKind.Semicolon)
{
errors.AppendLine("; expected");
return(false);
}
return(true);
}