kUML Desktop

The inspector lists the transitions that leave the active states, innermost state first, followed by the transitions inherited from composite parents ("inherited from …​"). Each row shows the result of its guard as a glyph and a word (✓ true, ✗ false, ⚠ error: …​), never by colour alone, and its trigger or "(completion)".

Every variable of the instance is shown with an editor for its type: a switch for booleans, a field for numbers (decimal numbers, 64-bit integers; NaN, Infinity and similar are rejected) and a field for text (at most 1000 characters). Enter or leaving the field applies, Esc discards, a bad value shows an inline message and changes nothing. Lists, objects and null are shown read-only, as are variables whose name the editor would not accept. Variables that guards read but nobody has set appear as "not set" with a Set action that prefills the add row; + Add variable creates new ones (names [A-Za-z_][A-Za-z0-9_]*, at most 64 characters, at most 64 variables).

While you scrub the trace, variables are read-only and show their values as of that position; the inspector then evaluates the guards with the current (possibly edited) guards, and says so. Sending an event from a scrub position forks the history there and the fork starts with those variables. A position in the middle of a step shows the variables from the start of that step, because changes made by effects are not part of the trace.

More…​ in the simulation bar opens the free event row. Its payload field takes a JSON object whose keys guards read as event.<key>. The payload is validated before anything is sent: at most 16 KiB, at most 8 levels of nesting, a JSON object at the top level, and no top-level key named name, id or timestamp. An invalid payload shows a message and disables Send; nothing is sent. ⌘+Enter or Ctrl+Enter in the payload field sends. The event buttons always send an empty payload.

The pencil in an inspector row edits that guard with a syntax-highlighted, type-checked editor (at most 4096 characters). Editing a protected transition asks for confirmation first. An edited guard carries an "edited" chip with the original struck through and a Restore button; a band above the list counts the edits. Edits live only in the running simulation: Reset restores every guard, variable and the trace to the script’s state. While you scrub, guard editing is disabled.