private bool Match(char ch)
{
if (stream.Peek() == ch)
{
stream.Next();
return(true);
}
return(false);
}
private Lexeme RecognizeOperator(char current)
{
if (".,();".Contains(current))
{
return(lexemeFactory.Create(lexemeMapper.MapsToLexeme("" + current)));
}
if ("+-*/".Contains(current))
{
switch (current)
{
case '+': return(lexemeFactory.Create(LexemeType.AddOp, OperationType.Addition));
case '-': return(lexemeFactory.Create(LexemeType.AddOp, OperationType.Subtraction));
case '/': return(lexemeFactory.Create(LexemeType.MulOp, OperationType.Division));
default: return(lexemeFactory.Create(LexemeType.MulOp, OperationType.Multiplication));
}
}
if (current == ':')
{
if (inputStream.Peek() == '=')
{
inputStream.Next();
return(lexemeFactory.Create(LexemeType.Assign));
}
else
{
throw new CompilerException(": with out matching =");
}
}
if (current == '<')
{
char next = inputStream.Peek();
if (next == '=')
{
inputStream.Next();
return(lexemeFactory.Create(LexemeType.RelOp, OperationType.LessThanOrEquals));
}
if (next == '>')
{
inputStream.Next();
return(lexemeFactory.Create(LexemeType.RelOp, OperationType.NotEqual));
}
return(lexemeFactory.Create(LexemeType.RelOp, OperationType.LessThan));
}
if (current == '=')
{
return(lexemeFactory.Create(LexemeType.RelOp, OperationType.Equal));
}
// this has to be true
if (current == '>')
{
char next = inputStream.Peek();
if (next == '=')
{
inputStream.Next();
return(lexemeFactory.Create(LexemeType.RelOp, OperationType.GreaterThanOrEquals));
}
return(lexemeFactory.Create(LexemeType.RelOp, OperationType.GreaterThan));
}
// we really can't get here
return(null);
}
