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Markup Formatting Reference

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Add an Invariant callout to the description of a symbol using the Invariant delimiter. Multiple Invariant callouts appear in the description section in the same order as they do in the markup.

Use the callout to display a condition that is guaranteed to be true during the execution of the documented symbol.

Works with:

  •     Playgrounds

  • ✓ Symbol documentation


  • * | + | - Invariant: description
  • optional continuation of description

The description displayed in Quick Help for the invariant callout is created as described in Parameters Section.


  1. /**
  2.  An example of using the invariant field
  3.  - Invariant:
  4.  The person reference will not change during the execution of this method
  5. */
image: ../Art/MFR_symbol_field_invariant_2x.png