internal static IEnumerable<Token> GetTokens(string template, string open = "{{", string close = "}}")
{
var index = 0;
while (index < template.Length)
{
var offset = index;
var brace = ScanBrace(template, open, ref index);
Token? text = null;
if (offset != brace)
{
text = new Token
{
Offset = offset,
Length = brace - offset,
Type = TagType.Text
};
}
var token = new Token();
index = SkipWhitespace(template, index);
if (index == template.Length)
{
if (text != null)
yield return (Token)text;
yield break;
}
if (template[index] != '!')
{
switch (template[index])
{
case '&':
token.Type = TagType.Escaped;
index = SkipWhitespace(template, index + 1);
break;
case '#':
token.Type = TagType.Loop;
index = SkipWhitespace(template, index + 1);
break;
case '/':
token.Type = TagType.End;
index = SkipWhitespace(template, index + 1);
break;
case '^':
token.Type = TagType.Inverted;
index = SkipWhitespace(template, index + 1);
break;
case '>':
token.Type = TagType.Partial;
index = SkipWhitespace(template, index + 1);
break;
default:
token.Type = TagType.Attribute;
break;
}
var start = index;
var end = ScanWord(template, start);
token.Offset = start;
token.Length = end - start;
ScanBrace(template, close, ref index);
if (token.Type == TagType.Loop || token.Type == TagType.Inverted || token.Type == TagType.End || token.Type == TagType.Partial)
{
Standalone(template, ref text, ref index);
}
if (text != null)
yield return (Token)text;
yield return token;
}
else
{
ScanBrace(template, close, ref index);
Standalone(template, ref text, ref index);
if (text != null)
yield return (Token)text;
}
}
}
private static void Standalone(string template, ref Token? text, ref int index)
{
int end = index;
while (end < template.Length)
{
if (template[end] == '\r')
{
end++;
if (end < template.Length && template[end] == '\n')
{
end++;
}
break;
}
if (template[end] == '\n')
{
end++;
break;
}
if (!char.IsWhiteSpace(template[end]))
return;
end++;
}
if (text != null)
{
var tok = (Token)text;
int start = tok.Offset + tok.Length - 1;
while (start >= 0)
{
if (template[start] == '\r' || template[start] == '\n')
break;
if (!char.IsWhiteSpace(template[start]))
return;
start--;
}
tok.Length = start < tok.Offset ? 0 : start - tok.Offset + 1;
text = tok.Length > 0 ? (Token?)tok : null;
}
index = end;
}