public List <TemplateSection> Parse(string text)
{
this.text = text;
var stack = new Stack <ParserStackEntry>();
while (!IsEOF())
{
if (LookingAt("{{"))
{
CaptureLiteralText();
if (LookingAt("{{#"))
{
position += 3;
string key = ExtractKey();
stack.Push(new ParserStackEntry {
key = key, sections = sections
});
sections = new List <TemplateSection>();
}
else if (LookingAt("{{/"))
{
position += 3;
string key = ExtractKey();
if (stack.Count == 0)
{
throw Error($"Found a close for '{key}', but no section is open.");
}
ParserStackEntry top = stack.Pop();
if (top.key != key)
{
throw Error($"Mismatched close; expected a close for '{top.key}' but got '{key}'.");
}
BlockTemplateSection section = new BlockTemplateSection(key, sections);
sections = top.sections;
sections.Add(section);
}
else
{
position += 2;
string key = ExtractKey();
sections.Add(new VariableReferenceTemplateSection(key));
}
literalStart = position;
}
else
{
position++;
}
}
CaptureLiteralText();
if (stack.Count > 0)
{
throw Error($"Unexpected end of template; did not find a close for section '{stack.Peek().key}'.");
}
return(sections);
}
static List <TemplateSection> ParseTemplate(string text)
{
int position = 0;
int literalStart = 0;
Stack <ParserStackEntry> stack = new Stack <ParserStackEntry>();
var sections = new List <TemplateSection>();
while (!IsEOF())
{
if (LookingAt("{{"))
{
CaptureLiteralText();
if (LookingAt("{{#"))
{
position += 3;
string key = ExtractKey();
stack.Push(new ParserStackEntry {
key = key, sections = sections
});
sections = new List <TemplateSection>();
}
else if (LookingAt("{{/"))
{
position += 3;
string key = ExtractKey();
if (stack.Count == 0)
{
throw Error($"Found a close for '{key}', but no section is open.");
}
ParserStackEntry top = stack.Pop();
if (top.key != key)
{
throw Error($"Mismatched close; expected a close for '{top.key}' but got '{key}'.");
}
NestedSection section = new NestedSection(key, sections);
sections = top.sections;
sections.Add(section);
}
else
{
position += 2;
string key = ExtractKey();
sections.Add(new VariableSection(key));
}
literalStart = position;
}
else
{
position++;
}
}
CaptureLiteralText();
if (stack.Count > 0)
{
throw Error($"Unexpected end of template; did not find a close for section '{stack.Peek().key}'.");
}
return(sections);
void CaptureLiteralText()
{
if (position != literalStart)
{
string literal = text.Substring(literalStart, position - literalStart);
sections.Add(new LiteralSection(literal));
}
}
bool IsEOF()
{
return(position >= text.Length);
}
Exception Error(string v)
{
throw new InvalidDataException($"{v} (at position {position}");
}
string ExtractKey()
{
if (IsEOF())
{
throw Error("Unexpected end of template; did not find '}}'");
}
int end = text.IndexOf("}}", position);
if (end < 0)
{
throw Error("Unexpected end of template; did not find '}}'");
}
string key = text.Substring(position, end - position);
position = end + 2;
return(key);
}
bool LookingAt(string token)
{
int i = position;
int j = 0;
while (i < text.Length)
{
if (j == token.Length)
{
return(true);
}
if (text[i] != token[j])
{
break;
}
i++; j++;
}
return(false);
}
}