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'OF' expected

Velox reports 'OF' expected when a supported construct has reached the point where of must connect its selector or container declaration to the following type or branch list.

Example​

procedure ScriptEvent(var Value: Variant);
begin
  case Value
    1: Value := 'one'; // Error: 'OF' expected
  end;
end;

Add of after the completed selector expression:

case Value of
  1: Value := 'one';
else
  Value := 'other';
end;

Compiler contexts​

The current modified PascalScript compiler emits the same diagnostic in four syntax families:

  • case Expression of before the first case label;
  • set of ElementType;
  • array[IndexRange] of ElementType and dynamic array of ElementType; and
  • array of ElementType in an open-array parameter declaration parsed by the routine-declaration helper.

The token following array, set or the case selector is not interchangeable across these forms. For example, a static array must close its ] before of.

Correction procedure​

  1. Identify whether the parser is in a case, set, array or parameter declaration.
  2. Complete the expression, range or closing bracket immediately before of.
  3. Insert the keyword at that grammar boundary.
  4. Check the following type or case label; a malformed preceding construct can make the reported token misleading.

Edge cases and quirks​

  • The message does not identify which of the four parser contexts emitted it.
  • In case, an error inside the selector expression can consume tokens up to the expected of; correct the earliest expression error first.
  • In an array declaration, a missing ] normally reports Closing square bracket expected before this message.
  • of in exception-handler syntax is handled by a different parser path and does not use this emission family.
  • case - selector types, labels and else behaviour.
  • Closing square bracket (']') expected - an unfinished array range.
  • Unknown type - of is present but the element type is unavailable.

External references​