public override void Accept(MatchExpression match)
{
bool hasCatchall = false;
bool hasTruePattern = false;
bool hasFalsePattern = false;
foreach (AstNode node in match.MatchCases)
{
var matchCase = node as CaseExpression;
if (matchCase != null)
{
var nameExpr = matchCase.Pattern as NameExpression;
if (nameExpr != null && nameExpr.Value == "_")
{
hasCatchall = true;
}
var trueExpr = matchCase.Pattern as TrueExpression;
if (trueExpr != null)
{
hasTruePattern = true;
}
var falseExpr = matchCase.Pattern as FalseExpression;
if (falseExpr != null)
{
hasFalsePattern = true;
}
}
}
bool isLegal = hasCatchall || (hasTruePattern && hasFalsePattern);
if (!isLegal)
{
errorLog.Add(Errors.MatchDoesNotAccountForAllConditions,
match.Location);
}
base.Accept(match);
}
Token NextToken()
{
var ch = source.Peek();
if (source.Peeks(2) == "0x")
{
return(ReadHexNumber());
}
if (char.IsDigit(ch))
{
return(ReadNumber());
}
if (char.IsLetter(ch) || ch == '_')
{
return(ReadIdentifier());
}
if (source.Peeks(3) == "/**")
{
ReadDocComment();
return(null);
}
if (source.Peeks(2) == "/*")
{
ReadLineComment();
return(null);
}
switch (ch)
{
case '\"':
case '\'':
return(ReadStringLiteral());
case '#':
source.SkipLine();
return(null);
}
var punctuators = new Dictionary <char, TokenClass> {
{ '{', TokenClass.OpenBrace },
{ '}', TokenClass.CloseBrace },
{ '(', TokenClass.OpenParan },
{ ')', TokenClass.CloseParan },
{ '[', TokenClass.OpenBracket },
{ ']', TokenClass.CloseBracket },
{ ';', TokenClass.SemiColon },
{ ':', TokenClass.Colon },
{ ',', TokenClass.Comma }
};
if (punctuators.ContainsKey(source.Peek()))
{
var punctuator = source.Read();
return(new Token(
punctuators [punctuator],
punctuator.ToString(),
lastDocStr,
source.Location
));
}
if (OperatorChars.Contains(source.Peek()))
{
return(ReadOperator());
}
if (char.IsLetter(ch))
{
return(ReadIdentifier());
}
errorLog.Add(Errors.UnexpectedToken, source.Location, source.Read());
return(null);
}