public bool ExpectRegister(out Registers register)
{
register = Registers.RegA;
if (this.IsAtEnd())
{
return(false);
}
else if (!this.ExpectLetter())
{
return(false);
}
string word = this.ScanWord();
if (!RegisterToken.IsKeywordValid(word))
{
return(false);
}
register = RegisterToken.GetTypeFromKeyword(word);
return(true);
}
private void Tokenize()
{
this.tokenStartLine = this.line;
this.tokenStartCol = this.col - 1;
while (!this.IsAtEnd())
{
char c = this.ReadNext();
tokenStartLine = this.line;
tokenStartCol = this.col - 1; // because `current` points to the next char
if (this.IsLetter(c))
{
Token tok;
string word = this.ScanWord(c);
if (InstructionToken.IsKeywordValid(word))
{
Instructions instr = InstructionToken.GetTypeFromKeyword(word);
tok = new InstructionToken(this.tokenStartLine, this.tokenStartCol, instr);
}
else if (RegisterToken.IsKeywordValid(word))
{
Registers reg = RegisterToken.GetTypeFromKeyword(word);
tok = new RegisterToken(this.tokenStartLine, this.tokenStartCol, reg);
}
else
{
this.LogUnknownKeywordError(word);
continue;
}
this.tokens.Add(tok);
}
else if (c == '#')
{
byte nb;
if (this.ExpectNumber(out nb))
{
var tok = new NumericalValueToken(this.tokenStartLine, this.tokenStartCol, nb);
this.tokens.Add(tok);
}
else
{
this.LogExpectedNumberError();
}
}
else if (c == '&')
{
Registers reg;
byte nb;
if (this.ExpectRegister(out reg))
{
var tok = new AddressRegisterToken(this.tokenStartLine, this.tokenStartCol, reg);
this.tokens.Add(tok);
}
else if (this.ExpectNumber(out nb))
{
var tok = new AddressValueToken(this.tokenStartLine, this.tokenStartCol, nb);
this.tokens.Add(tok);
}
else
{
this.LogUnexpectedTokenForAddressError();
}
}
else if (c != '\0')
{
this.LogUnexpectedCharError(c);
//continue;
}
}
if (this.errorsCount != 0)
{
Console.WriteLine(this.errorsCount + " errors found.");
Console.WriteLine("---");
throw new SyntaxErrorsException();
}
}