private static ScannerResult ScanDotOperatorToken(SourceReader reader)
{
(var sourceChar, var nextReader) = reader.Read('.');
var extent = SourceExtent.From(sourceChar);
return(new ScannerResult(new DotOperatorToken(extent), nextReader));
}
private static ScannerResult ScanIdentifierToken(SourceReader reader)
{
var thisReader = reader;
var sourceChar = default(SourceChar);
var sourceChars = new List <SourceChar>();
var nameChars = new StringBuilder();
// firstIdentifierChar
(sourceChar, thisReader) = thisReader.Read(ArmStringValidator.IsFirstIdentifierChar);
sourceChars.Add(sourceChar);
nameChars.Append(sourceChar.Value);
// *( nextIdentifierChar )
while (!thisReader.Eof() && thisReader.Peek(ArmStringValidator.IsNextIdentifierChar))
{
(sourceChar, thisReader) = thisReader.Read();
sourceChars.Add(sourceChar);
nameChars.Append(sourceChar.Value);
}
// return the result
var extent = SourceExtent.From(sourceChars);
var name = nameChars.ToString();
return(new ScannerResult(
new IdentifierToken(extent, name), thisReader
));
}
private static ScannerResult ScanCloseParenToken(SourceReader reader)
{
(var sourceChar, var nextReader) = reader.Read(')');
var extent = SourceExtent.From(sourceChar);
return(new ScannerResult(new CloseParenToken(extent), nextReader));
}
private static ScannerResult ScanOpenBracketToken(SourceReader reader)
{
(var sourceChar, var nextReader) = reader.Read('[');
var extent = SourceExtent.From(sourceChar);
return(new ScannerResult(new OpenBracketToken(extent), nextReader));
}
private static ScannerResult ScanStringLiteralToken(SourceReader reader)
{
const char SINGLEQUOTE = '\'';
var thisReader = reader;
var sourceChar = default(SourceChar);
var sourceChars = new List <SourceChar>();
var stringChars = new StringBuilder();
// read the first single-quote
(sourceChar, thisReader) = thisReader.Read(SINGLEQUOTE);
sourceChars.Add(sourceChar);
// read the remaining characters
var isTerminated = false;
while (!thisReader.Eof())
{
var peek = thisReader.Peek();
sourceChars.Add(peek);
if (peek.Value == SINGLEQUOTE)
{
thisReader = thisReader.Next();
if (!thisReader.Eof() && (thisReader.Peek().Value == SINGLEQUOTE))
{
// an escaped single-quote (i.e. "''")
sourceChars.Add(peek);
stringChars.Append(SINGLEQUOTE);
thisReader = thisReader.Next();
}
else
{
// the closing single-quote character
isTerminated = true;
break;
}
}
else
{
// we just read a literal string character
stringChars.Append(peek.Value);
thisReader = thisReader.Next();
}
}
// make sure we found the end of the string
if (!isTerminated)
{
throw new InvalidOperationException("Unterminated string found.");
}
// return the result
var extent = SourceExtent.From(sourceChars);
var stringValue = stringChars.ToString();
return(new ScannerResult(
new StringLiteralToken(extent, stringValue), thisReader
));
}
public Lexer AddScanner(char value, Func <SourceExtent, SyntaxToken> factoryMethod)
{
return(this.AddScanner(
value,
(reader) => {
(var sourceChar, var nextReader) = reader.Read(value);
var extent = SourceExtent.From(sourceChar);
return new ScannerResult(
factoryMethod(extent), nextReader
);
}
));
}
private static ScannerResult ScanIntegerToken(SourceReader reader)
{
var thisReader = reader;
var sourceChar = default(SourceChar);
var sourceChars = new List <SourceChar>();
var sign = 1;
var value = 0;
// read the sign
switch (thisReader.Peek().Value)
{
case '-':
sign = -1;
(sourceChar, thisReader) = thisReader.Read('-');
sourceChars.Add(sourceChar);
break;
case '+':
sign = +1;
(sourceChar, thisReader) = thisReader.Read('+');
sourceChars.Add(sourceChar);
break;
}
// digit
(sourceChar, thisReader) = thisReader.Read(ArmStringValidator.IsDigit);
sourceChars.Add(sourceChar);
value = value * 10 + (sourceChar.Value - '0');
// *( digit )
while (!thisReader.Eof() && thisReader.Peek(ArmStringValidator.IsDigit))
{
(sourceChar, thisReader) = thisReader.Read();
sourceChars.Add(sourceChar);
value = value * 10 + (sourceChar.Value - '0');
}
// return the result
var extent = SourceExtent.From(sourceChars);
return(new ScannerResult(
new IntegerToken(extent, sign * value), thisReader
));
}
private static ScannerResult ScanWhitespaceToken(SourceReader reader)
{
var thisReader = reader;
var sourceChar = default(SourceChar);
var sourceChars = new List <SourceChar>();
// read the first whitespace character
(sourceChar, thisReader) = thisReader.Read(ArmStringValidator.IsWhitespace);
sourceChars.Add(sourceChar);
// read the remaining whitespace
while (!thisReader.Eof() && thisReader.Peek(ArmStringValidator.IsWhitespace))
{
(sourceChar, thisReader) = thisReader.Read();
sourceChars.Add(sourceChar);
}
// return the result
var extent = SourceExtent.From(sourceChars);
var value = extent.ToString();
return(new ScannerResult(
new WhitespaceToken(extent, value), thisReader
));
}