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Global State and Clocks Reference

Global State

The <GlobalState> element declares variables that persist throughout the entire lifecycle of the automaton instance. These variables form the automaton's working memory.

<GlobalState>
  <Variable Name="orderId" Type="string"/>
  <Variable Name="retryCount" Type="int" Value="0"/>
  <Variable Name="shopifyApiEndpoint" Type="string" Desc="Shopify API endpoint"/>
</GlobalState>

Variable attributes

Attribute Required Description
Name Yes Identifier used to reference the variable throughout the automaton
Type No Data type hint. Common values: string, int, boolean, list, object, ArrayList, map[string,int]
Value No Default value assigned when the automaton is instantiated
Desc No Human-readable description. Used as documentation only.
IO No Indicates whether the variable is an input (I), output (O), or both (I/O) for parameter passing purposes
Starred No Marks the variable as starred. Behavior is platform-dependent.

Referencing variables

Global state variables are referenced by name in:

  • <Parameter LocalVariable="..."> elements in Input and Output blocks
  • Clock constraint expressions when a variable stores a threshold value
  • TransitionNew target selection when Type references a global state variable

When the designer serializes a variable reference that matches a global state variable name, it automatically prepends this.GLOBALSTATE_ to the value in the XAL output. This prefix is handled transparently — you do not need to type it manually in the designer.

Clocks

The <Clocks> element declares timer variables used in transition conditions.

<Clocks>
  <Variable Name="clk_retry"/>
  <Variable Name="clk_handshake"/>
</Clocks>

Clock variable attributes

Attribute Required Description
Name Yes Identifier used in ClockConstraint and ClockReset elements

Clocks have no type, value, or description — they are pure timers. A clock starts counting from zero when it is reset by a <ClockReset> element on a transition.

Clock constraint syntax

<ClockConstraint ClockExp="clk_retry &lt; T_max_wait"/>
<ClockConstraint ClockExp="clk_auth &gt;= T_auth_timeout"/>

The ClockExp attribute contains the comparison expression. Use XML-escaped operators:

Operator XML encoding
< &lt;
<= &lt;=
> &gt;
>= &gt;=

The right-hand side of the expression is typically a named constant (e.g. T_max_wait) whose value is configured at the platform level, or a literal number with a unit suffix (e.g. 5 min, 30 min).

Clock reset

<ClockReset ClockVar="clk_retry"/>

Resets the specified clock to zero when the transition fires. Multiple <ClockReset> elements can appear on a single transition.