/// <summary>Parse a template description into tokens</summary>
private static IEnumerable <Token> Parse(Src src, bool root = false)
{
// Recursively build the token tree
for (; Extract.AdvanceToNonDelim(src, " \t\r\n");)
{
switch (src)
{
case TemplateMark:
{
src.Next(); // Skip the '*'
var flags = ETemplateFlags.Recursive;
if (!root)
{
flags |= ETemplateFlags.Hidden;
flags &= ~ETemplateFlags.Recursive;
}
if (src == HiddenMark)
{
src.Next();
flags |= ETemplateFlags.Hidden;
flags &= ~ETemplateFlags.Recursive;
}
if (src == RootLevelOnlyMark)
{
src.Next();
flags |= ETemplateFlags.RootLevelOnly;
flags &= ~ETemplateFlags.Recursive;
}
// Read the template keyword
var keyword = Extract.Identifier(out var kw, src) ? kw : throw new ScriptException(Script.EResult.InvalidValue, src.Location, $"Invalid template keyword");
// Buffer the remaining template description
var len = BufferTemplateDeclaration(src);
// Create the template instance
var remaining = src.Limit - len;
using (var limit = Scope.Create(() => src.Limit = len, () => src.Limit = remaining))
yield return(new Template(keyword, flags, Parse(src)));
break;
}
case ReferenceMark:
case ExpandMark:
{
// Skip the '@' or '$'
var expand = src == ExpandMark;
src.Next();
// Read the keyword of the referenced template
var keyword = Extract.Identifier(out var kw, src) ? kw : throw new ScriptException(Script.EResult.InvalidValue, src.Location, $"Invalid template keyword");
yield return(new TemplateRef(keyword, expand));
break;
}
case '{':
case '}':
{
if (src == '{')
{
src.Next();
}
else
{
throw new ScriptException(Script.EResult.TokenNotFound, src.Location, "Unmatched '}' token");
}
// Buffer the content within the section
int len = 0;
for (var nest = 1; src[len] != 0 && nest != 0; ++len)
{
nest += src[len] == '{' ? 1 : 0;
nest -= src[len] == '}' ? 1 : 0;
}
if (src[len - 1] != '}')
{
throw new ScriptException(Script.EResult.TokenNotFound, src.Location, "Unmatched '{' token");
}
var remaining = src.Limit - (len - 1);
using (var limit = Scope.Create(() => src.Limit = len - 1, () => src.Limit = remaining))
yield return(new Section(Parse(src)));
src.Next();
break;
}
case '[':
case ']':
{
if (src == '[')
{
src.Next();
}
else
{
throw new ScriptException(Script.EResult.TokenNotFound, src.Location, "Unmatched ']' token");
}
// Buffer the content within the optional
int len = 0;
for (var nest = 1; src[len] != 0 && nest != 0; ++len)
{
nest += src[len] == '[' ? 1 : 0;
nest -= src[len] == ']' ? 1 : 0;
}
if (src[len - 1] != ']')
{
throw new ScriptException(Script.EResult.TokenNotFound, src.Location, "Unmatched '[' token");
}
var remaining = src.Limit - (len - 1);
using (var limit = Scope.Create(() => src.Limit = len - 1, () => src.Limit = remaining))
yield return(new Optional(Parse(src)));
src.Next();
break;
}
case '(':
case ')':
{
if (src == '(')
{
src.Next();
}
else
{
throw new ScriptException(Script.EResult.TokenNotFound, src.Location, "Unmatched ')' token");
}
// Buffer the content within the repeat
int len = 0;
for (var nest = 1; src[len] != 0 && nest != 0; ++len)
{
nest += src[len] == '(' ? 1 : 0;
nest -= src[len] == ')' ? 1 : 0;
}
if (src[len - 1] != ')')
{
throw new ScriptException(Script.EResult.TokenNotFound, src.Location, $"Unmatched '(' token");
}
var remaining = src.Limit - (len - 1);
using (var limit = Scope.Create(() => src.Limit = len - 1, () => src.Limit = remaining))
yield return(new Repeat(Parse(src)));
src.Next();
break;
}
case '<':
case '>':
{
if (src == '<')
{
src.Next();
}
else
{
throw new ScriptException(Script.EResult.TokenNotFound, src.Location, $"Unmatched '>' token");
}
var name = Extract.Identifier(out var kw, src) ? kw : throw new ScriptException(Script.EResult.InvalidValue, src.Location, $"Invalid field identifier");
if (src != '>')
{
throw new ScriptException(Script.EResult.TokenNotFound, src.Location, $"Unmatched '<' token");
}
yield return(new Field(name));
src.Next();
break;
}
case '|':
{
yield return(new Select());
src.Next();
break;
}
case ';':
{
yield return(new LineBreak());
src.Next();
break;
}
default:
{
// Literal text
Extract.BufferWhile(src, (s, i) => !" \n*@{}[]()<>|".Contains(s[i]) ? 1 : 0, 0, out var len);
yield return(new Literal(src.Buffer.ToString(0, len)));
src.Next(len);
break;
}
}
}
}