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Opening square brackets ('[') expected

In the current Velox compiler, Opening square brackets ('[') expected has one emission site: an interface type declaration has completed interface(AncestorInterface) and must begin its GUID clause.

Example​

type
  IExample = interface(IInterface)
    '{11111111-1111-1111-1111-111111111111}' // Error: opening [ expected
  end;

Put the single-quoted GUID inside square brackets:

type
  IExample = interface(IInterface)
    ['{11111111-1111-1111-1111-111111111111}']
  end;

The GUID above is fictional and used only as a syntax example.

How Velox detects it​

The modified PascalScript type parser performs these checks in sequence:

  1. interface must be followed by (AncestorInterface).
  2. The next token must be [.
  3. The next token must be a string literal containing the GUID text.
  4. The GUID is converted to a Delphi TGUID.
  5. The parser requires the closing ] before interface members.

Failure at step 2 emits ecOpenBlockExpected. An invalid string value reaches the Delphi GUID conversion and produces that conversion exception as a custom compiler error instead.

Edge cases and quirks​

  • This message is not emitted for an array/index expression missing [. Those grammar paths usually produce another expression or parameter diagnostic.
  • The brackets are required by the current compiled path unless the PascalScript library is built with PS_NOINTERFACEGUIDBRACKETS; the current Velox project configuration does not define that symbol.
  • Delphi can declare some non-COM interfaces without an explicit ancestor or GUID. This embedded parser path is stricter and requires both.
  • Interface declarations are an advanced compiler feature; most Velox scripts consume registered class/interface types rather than declare new ones.
  • String Expected - the opening bracket exists but the GUID string token does not.
  • Closing square bracket (']') expected - the GUID clause is not closed.
  • Opening parenthesis ('(') expected - the interface ancestor clause is missing.

External references​