Represents an SCXML <foreach> action for iterating over collections.

The foreach action iterates over a collection (array), executing a block of actions for each item. It provides both the item value and optionally the index to the actions.

Attributes

• array - The expression that evaluates to the collection to iterate over (required)
• item - The variable name to assign each collection item to (required)
• index - The variable name to assign the current index to (optional)
• actions - List of executable actions to run for each iteration
• source_location - Location in the source SCXML for error reporting

Examples

<foreach array="myArray" item="currentItem" index="currentIndex">
    <assign location="sum" expr="sum + currentItem"/>
    <assign location="indexSum" expr="indexSum + currentIndex"/>
</foreach>

<foreach array="users" item="user">
    <log expr="user.name"/>
</foreach>

SCXML Specification

From the W3C SCXML specification:

• The foreach element must have 'array' and 'item' attributes
• The 'index' attribute is optional
• The processor must declare new variables if item/index don't exist
• Variables are restored to their previous values after foreach completes
• If 'array' doesn't evaluate to an iterable collection, error.execution is raised
• Iteration proceeds from first to last item in collection order

Variable Scoping

The foreach element implements proper variable scoping:

• Creates snapshot of current datamodel before execution
• Declares item/index variables if they don't exist
• Restores original variable values after foreach completion
• Inner foreach loops properly nest variable scopes