// This code is pretty hairy - the problem is
// distinguishing between:
// 1. a floating point number, which may be
// in scientific notification, and might simply begin
// with "."
// 2. A symbol with a dot in it
// 3. Just a lone "." used for separating lists
// It's doubtful that it's entirely correct - but if you find a bug,
// add it as a test to ScannerTest and amend this logic.
private static TokenType?matchNumber(Scanner s)
{
if (s.peek() == '.')
{
return(leadingFloat(s));
}
if (s.isOneOf("+-"))
{
s.readChar();
if (s.peek() == '.')
{
return(leadingFloat(s));
}
var num = unsignedNumber(s);
if (num != null)
{
return(num);
}
matchSymbol(s);
return(TokenType.Symbol);
}
return(unsignedNumber(s));
}
// TODO:
// WE should implement actual reader macros for this part of things.
private static TokenType?matchHash(Scanner s)
{
if (s.peek() != '#')
{
return(null);
}
s.readChar();
if (s.peek() == '(')
{
s.readChar();
return(TokenType.VectorOpen);
}
if (s.isOneOf("tfTF"))
{
s.readChar();
return(TokenType.Boolean);
}
throw s.fail("Unrecognized token");
}
private static TokenType?readExponent(Scanner s)
{
s.readChar(); // Skip exponent market
var read = false;
if (s.isOneOf("+-"))
{
s.readChar();
read = true;
}
while (s.isDigit())
{
read = true;
s.readChar();
}
if (read)
{
return(TokenType.Double);
}
// It's not a floating point number in exponent format.
// Read it as a symbol instead.
matchSymbol(s);
return(TokenType.Symbol);
}
// TODO:
// WE should implement actual reader macros for this part of things.
private static TokenType? matchHash(Scanner s)
{
if (s.peek() != '#')
return null;
s.readChar();
if(s.peek() == '(')
{
s.readChar();
return TokenType.VectorOpen;
}
if(s.isOneOf("tfTF"))
{
s.readChar();
return TokenType.Boolean;
}
throw s.fail("Unrecognized token");
}
// This code is pretty hairy - the problem is
// distinguishing between:
// 1. a floating point number, which may be
// in scientific notification, and might simply begin
// with "."
// 2. A symbol with a dot in it
// 3. Just a lone "." used for separating lists
// It's doubtful that it's entirely correct - but if you find a bug,
// add it as a test to ScannerTest and amend this logic.
private static TokenType? matchNumber(Scanner s)
{
if(s.peek() == '.')
return leadingFloat(s);
if(s.isOneOf("+-"))
{
s.readChar();
if(s.peek() == '.')
return leadingFloat(s);
var num = unsignedNumber(s);
if (num != null)
return num;
matchSymbol(s);
return TokenType.Symbol;
}
return unsignedNumber(s);
}
private static TokenType? readExponent(Scanner s)
{
s.readChar(); // Skip exponent market
var read = false;
if (s.isOneOf("+-"))
{
s.readChar();
read = true;
}
while (s.isDigit())
{
read = true;
s.readChar();
}
if(read)
return TokenType.Double;
// It's not a floating point number in exponent format.
// Read it as a symbol instead.
matchSymbol(s);
return TokenType.Symbol;
}
