/// <summary>
/// Check if a function declaration is incoming
/// </summary>
/// <returns></returns>
public Boolean CheckFunctionIncoming()
{
//Starting with a type can mean a function
if (!Database.CheckType(CurrentToken.Value))
return false;
//Record the index of the present token so we look forward and come back again
Int32 currentIndex = TokenIndex;
NextToken();
//Skip the *s
//while (CurrentToken.Value.Equals("*"))
//NextToken();
NextToken();
//A '(' after a type name mean's the function's parameter list is incoming, so this is a function
//declaration
Boolean retVal;
retVal = CurrentToken.Value.Equals("(");
//Reset the tokenIndex
TokenIndex = currentIndex;
CurrentToken = Tokens[currentIndex];
return retVal;
}
/// <summary>
/// Resets the tokens
/// </summary>
protected void ResetToken()
{
TokenIndex = 0;
CurrentToken = Tokens[TokenIndex];
}
protected void PreviousToken()
{
TokenIndex--;
CurrentToken = Tokens[TokenIndex];
}
/// <summary>
/// Moves onto the next token
/// </summary>
protected void NextToken()
{
TokenIndex++;
try
{
CurrentToken = Tokens[TokenIndex];
}
catch
{
CurrentToken = new Token();
CurrentToken.LineStart = Int32.MaxValue;
CurrentToken.Type = TokenType.Symbol;
}
}
/// <summary>
/// Reads the next token in the program
/// </summary>
TokenType GetNextToken()
{
CurrentToken = new Token();
SkipWhitespace();
//Setup the base of the token
CurrentToken.LineStart = LineStart;
CurrentToken.CharacterPosition = CharacterPosition - LineStart + 1;
//EOL token
if (Program[CharacterPosition].Equals('\n'))
{
CurrentToken.Type = TokenType.EOL;
return TokenType.EOL;
}
//Number token
if ((char.IsDigit(Program[CharacterPosition])) ||
(Program[CharacterPosition].Equals('.') && char.IsDigit(Program[CharacterPosition + 1])))
return GetNumber();
//Identifier token
if ((char.IsLetterOrDigit(Program[CharacterPosition])) ||
(Program[CharacterPosition].Equals('_') && char.IsLetterOrDigit(Program[CharacterPosition + 1])))
return GetIdentifier();
//Character token
if (Program[CharacterPosition].Equals('\"'))
return GetString();
//Symbol token
if ("!\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~".Contains(Program[CharacterPosition]))
return GetSymbol();
Error("Unrecognised Token", LineStart, CharacterPosition - LineStart + 1);
return TokenType.Unknown;
}
/// <summary>
/// Does all the preparsing of the three sections
/// </summary>
public void Preparse()
{
ResetToken();
ParseTypesDeclarations();
ResetToken();
ParseGlobalVariableDeclarations();
//Wrap in void main
Token v = new Token(TokenType.Identifier, "VOID");
Token m = new Token(TokenType.Identifier, "MAIN");
Token pl = new Token(TokenType.Symbol, "(");
Token pr = new Token(TokenType.Symbol, ")");
Token bl = new Token(TokenType.Symbol, "{");
Token br = new Token(TokenType.Symbol, "}");
Tokens.Insert(0, bl);
Tokens.Insert(0, pr);
Tokens.Insert(0, pl);
Tokens.Insert(0, m);
Tokens.Insert(0, v);
Tokens.Add(br);
ResetToken();
ParseFunctionDeclarations();
}
