static IEnumerable <TemplateToken> Parse(string text)
{
var scanner = new TextScanner(text);
while (true)
{
// Find the next start tag
var endOfLastToken = scanner.Position;
var startTag = scanner.ScanTo(StartTag);
if (!startTag.HasValue)
{
// No more start tags found, emit remaining text token
yield return(new TemplateText(text, endOfLastToken, scanner.End));
yield break;
}
// Otherwise emit text between end of last token and the start tag
yield return(new TemplateText(text, endOfLastToken, startTag.Value));
// Find the next end tag
var afterStartTag = scanner.Position;
var endTag = scanner.ScanTo(EndTag);
if (!endTag.HasValue)
{
throw new TemplateParseError("Couldn't find closing '" + EndTag + "'", startTag.Value.ToPosition(text));
}
// emit the text between the start and end tag
yield return(new TemplateVariable(text.Substring(afterStartTag, endTag.Value - afterStartTag)));
}
}