Ast.SyntaxNode _GetExpression(FtlParserStream ps)
{
ps.SkipInlineWs();
var selector = GetSelectorExpression(ps);
ps.SkipInlineWs();
if (ps.CurrentIs('-'))
{
ps.Peek();
if (!ps.CurrentPeekIs('>'))
{
ps.ResetPeek();
return(selector);
}
if (selector is Ast.MessageReference)
{
throw new ParseException("E0016");
}
if (selector is Ast.AttributeExpression ae &&
ae.Ref is Ast.MessageReference)
{
throw new ParseException("E0018");
}
if (selector is Ast.VariantExpression)
{
throw new ParseException("E0017");
}
ps.Next();
ps.Next();
ps.SkipInlineWs();
var variants = GetVariants(ps);
if (variants.Count == 0)
{
throw new ParseException("E0011");
}
// VariantLists are only allowed in other VariantLists.
if (variants.Any(v => v.Value is Ast.VariantList))
{
throw new ParseException("E0023");
}
ps.ExpectIndent();
return(new Ast.SelectExpression(selector, variants));
}
else if (selector is Ast.AttributeExpression ae &&
ae.Ref is Ast.TermReference)
{
throw new ParseException("E0019");
}
return(selector);
}