/**
* Breaks up the given `template` string into a tree of tokens. If the `tags`
* argument is given here it must be an array with two string values: the
* opening and closing tags used in the template (e.g. [ "<%", "%>" ]). Of
* course, the default is to use mustaches (i.e. mustache.tags).
*
* A token is an array with at least 4 elements. The first element is the
* mustache symbol that was used inside the tag, e.g. "#" or "&". If the tag
* did not contain a symbol (i.e. {{myValue}}) this element is "Name". For
* all text that appears outside a symbol this element is "text".
*
* The second element of a token is its "Value". For mustache tags this is
* whatever else was inside the tag besides the opening symbol. For text tokens
* this is the text itself.
*
* The third and fourth elements of the token are the Start and End indices,
* respectively, of the token in the original template.
*
* Tokens that are the root node of a subtree contain two more elements: 1) an
* array of tokens in the subtree and 2) the index in the original template at
* which the closing tag for that section begins.
*/
private static List<Token> ParseTemplate(string template, Tags tags = null)
{
if (!template.Any())
return new List<Token>();
var sections = new Stack<Token>(); // Stack to hold section tokens
var tokens = new List<Token>(); // Buffer to hold the tokens
var spaces = new Stack<int>(); // Indices of whitespace tokens on the current line
var hasTag = false; // Is there a {{tag}} on the current line?
var nonSpace = false; // Is there a non-space char on the current line?
// Strips all whitespace tokens array for the current line
// if there was a {{#tag}} on it and otherwise only space.
Action stripSpace = () =>
{
if (hasTag && !nonSpace)
{
while (spaces.Any())
tokens.RemoveAt(spaces.Pop());
}
else
{
spaces.Clear();
}
hasTag = false;
nonSpace = false;
};
// TODO: this `= null` is to avoid "Use of unassigned local variable" C# compiler error.
Regex openingTagRe = null;
Regex closingTagRe = null;
Regex closingCurlyRe = null;
Action<Tags> compileTags = delegate(Tags tagsToCompile)
{
openingTagRe = new Regex(Regex.Escape(tagsToCompile.Opener) + "\\s*");
closingTagRe = new Regex("\\s*" + Regex.Escape(tagsToCompile.Closer));
closingCurlyRe = new Regex("\\s*" + Regex.Escape('}' + tagsToCompile.Closer));
};
if (tags == null)
compileTags(MustacheTags);
else
compileTags(tags);
//var Start, Type, Value, chr, token, openSection;
var scanner = new Scanner(template);
Token openSection = null;
while (!scanner.Eos())
{
var start = scanner._pos;
var value = scanner.ScanUntil(openingTagRe);
var valueLength = value.Length;
if (valueLength > 0)
{
for (var i = 0; i < valueLength; ++i)
{
string chr = "" + value[i];
if (IsWhitespace(chr))
{
spaces.Push(tokens.Count);
}
else
{
nonSpace = true;
}
tokens.Add(new Token {Type = "text", Value = chr, Start = start, End = start + 1});
start += 1;
// Check for whitespace on the current line.
if (chr == "\n")
stripSpace();
}
}
// Match the opening tag.
if (!scanner.Scan(openingTagRe).Any())
break;
hasTag = true;
// Get the tag Type.
var scanTag = scanner.Scan(_tagRe);
string type;
if (!scanTag.Any())
type = "Name";
else
type = scanTag;
scanner.Scan(_whiteRe);
// Get the tag Value.
switch (type)
{
case "=":
value = scanner.ScanUntil(_equalsRe);
scanner.Scan(_equalsRe);
scanner.ScanUntil(closingTagRe);
break;
case "{":
value = scanner.ScanUntil(closingCurlyRe);
scanner.Scan(_curlyRe);
scanner.ScanUntil(closingTagRe);
type = "&";
break;
default:
value = scanner.ScanUntil(closingTagRe);
break;
}
// Match the closing tag.
if (!scanner.Scan(closingTagRe).Any())
throw new Exception("Unclosed tag at " + scanner._pos);
var arr = value.Split('|');
string format = null;
if (arr.Length == 2)
{
value = arr[0];
format = arr[1];
}
var token = new Token {Type = type, Value = value, Format = format, Start = start, End = scanner._pos};
tokens.Add(token);
switch (type)
{
case "#":
case "^":
sections.Push(token);
break;
case "/":
// Check section nesting.
openSection = sections.Pop();
if (openSection == null)
throw new Exception("Unopened section \"" + value + "\" at " + start);
if (openSection.Value != value)
throw new Exception("Unclosed section \"" + openSection.Value + "\" at " + start);
break;
case "Name":
case "{":
case "&":
nonSpace = true;
break;
case "=":
// Set the tags for the next time around.
var newTags = _spaceRe.Split(value, 2);
compileTags(new Tags {Opener = newTags[0], Closer = newTags[1]});
break;
}
}
// Make sure there are no open sections when we're done.
if (sections.Any())
{
openSection = sections.Pop();
throw new Exception("Unclosed section \"" + openSection.Value + "\" at " + scanner._pos);
}
return NestTokens(SquashTokens(tokens));
}