// {{else if a=b}} {{else}} {{/name}}
// ^
// returns ^ ^
static ReadOnlyMemory <char> ParseElseStatement(this ReadOnlyMemory <char> literal, string blockName, out PageElseBlock statement)
{
var inStatements = 0;
var pos = 0;
statement = null;
var statementPos = -1;
var elseExpr = default(ReadOnlyMemory <char>);
while (true)
{
pos = literal.IndexOf("{{", pos);
if (pos == -1)
{
throw new SyntaxErrorException($"End block for 'else' not found.");
}
var c = literal.SafeGetChar(pos + 2);
if (c == '#')
{
inStatements++;
pos = literal.IndexOf("}}", pos) + 2; //end of expression
}
else if (c == '/')
{
if (inStatements == 0)
{
literal.Slice(pos + 2 + 1).ParseVarName(out var name);
if (name.EqualsOrdinal(blockName))
{
var body = ParseTemplatePage(literal.Slice(statementPos, pos - statementPos).TrimFirstNewLine());
statement = new PageElseBlock(elseExpr, body);
return(literal.Slice(pos));
}
}
inStatements--;
}
else if (literal.Slice(pos + 2).StartsWith("else"))
{
if (inStatements == 0)
{
if (statementPos >= 0)
{
var bodyText = literal.Slice(statementPos, pos - statementPos).TrimFirstNewLine();
var body = ParseTemplatePage(bodyText);
statement = new PageElseBlock(elseExpr, body);
return(literal.Slice(pos));
}
var endExprPos = literal.IndexOf("}}", pos);
if (endExprPos == -1)
{
throw new SyntaxErrorException($"End expression for 'else' not found.");
}
var exprStartPos = pos + 2 + 4; //= {{else...
elseExpr = literal.Slice(exprStartPos, endExprPos - exprStartPos).Trim();
statementPos = endExprPos + 2;
}
}
pos += 2;
}
}
/// <summary>
/// Gets the else call trace.
/// </summary>
/// <param name="fragment">The fragment.</param>
/// <returns>System.String.</returns>
protected virtual string GetElseCallTrace(PageElseBlock fragment) => "Block: " + Name + " > Else" +
(fragment.Argument.IsNullOrEmpty() ? "" : " (" + fragment.Argument + ")");
protected bool Equals(PageElseBlock other)
{
return(Argument.Span.SequenceEqual(other.Argument.Span) &&
Body.EquivalentTo(other.Body) &&
Equals(BodyStatement, other.BodyStatement));
}
/// <summary>
/// Write else as an asynchronous operation.
/// </summary>
/// <param name="scope">The scope.</param>
/// <param name="fragment">The fragment.</param>
/// <param name="token">The cancellation token that can be used by other objects or threads to receive notice of cancellation.</param>
/// <returns>A Task representing the asynchronous operation.</returns>
protected virtual async Task WriteElseAsync(ScriptScopeContext scope, PageElseBlock fragment, CancellationToken token)
{
await WriteAsync(scope, fragment.Body, GetElseCallTrace(fragment), token).ConfigAwait();
}
