FlexiRule Docs

Assignment

Perform sequential batch state mutations on document fields and context variables.

Assignment Action#

The Assignment action (formerly Set Value) is the primary mechanism for state mutation in FlexiRule. It allows you to define a sequence of mutations—Batch Assignments—that are executed in order to update document fields or manage internal rule state.

Purpose#

Use the Assignment action when you need to:

Update fields on the triggering document (e.g., change status to “Approved”).
Initialize or update context variables (vars) to store intermediate calculation results.
Perform mathematical operations (Increment, Decrement) on numeric fields.
Manage collections (Append to lists, Merge dictionaries).

Action Capabilities#

Capability	Support	Notes
Batch Execution	✅ Yes	Execute multiple assignments in a single node.
Conditional Rows	✅ Yes	Each assignment row can have its own `when` condition.
Multi-Operator	✅ Yes	Supports Set, Clear, Increment, Decrement, Append, Merge, and Toggle.
Data Normalization	✅ Yes	Integrated pipelines for cleaning and transforming data.
Value Resolution	✅ Yes	Unified resolver for static values, formulas, and complex lookups.

Configuration#

The Assignment action uses a grid-based interface where each row represents one mutation.

1. Target Path#

Defines where the value will be stored.

doc.field_name: Updates a field on the current document.
vars.variable_name: Sets a temporary variable available for the rest of the rule execution.

2. Operator#

Defines how the value is applied:

Set: Replaces the current value with the new value.
Clear: Removes the value (sets to None or empty).
Increment / Decrement: Adds or subtracts from the current numeric value.
Append: Adds a value to the end of a list/array.
Merge: Merges a dictionary into the target dictionary.
Toggle: Swaps a boolean value between true and false.

3. Value#

The new value or operand. This can be:

Static Value: A hardcoded string, number, or date.
Variable Path: A reference to another field (e.g., doc.base_amount).
Formula: A Python-based expression for calculations.
Data Pipeline: A sequence of normalization steps (e.g., Trim → Uppercase).

4. Condition (When)#

An optional expression that must evaluate to true for this specific assignment to run. This allows for complex “If-Else” logic within a single Assignment block.

Best Practices#

Use Variables for Clarity: Instead of repeating a complex formula in multiple nodes, calculate it once and store it in a vars.total_price variable.
Sequential Logic: Remember that assignments run from top to bottom. If row 2 depends on the result of row 1, it will work correctly.
Event Awareness: FlexiRule prevents you from mutating doc.* fields during “After Save” or “On Submit” events to prevent database inconsistencies. Use “Before Save” for field updates.

Common Mistakes#

Incorrect Path: Forgetting the doc. or vars. prefix. status will fail; doc.status will succeed.
Type Mismatch: Trying to Increment a text field or Append to a number.
Infinite Loops: Setting a field that triggers the same rule again (though FlexiRule has built-in cycle detection to catch this).

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