Evaluate() for dynamic expressions

Expert

Use Evaluate() to execute a FileMaker expression stored as text, enabling runtime-configurable calculations and formula fields.

What you'll learn

How Evaluate() executes a text string as a calculation
How to pass current field values into an evaluated expression
When Evaluate() is appropriate and when to avoid it

Evaluate() takes a text string and executes it as a FileMaker calculation expression, returning the result. This enables user-defined formulas stored in fields, formula-driven conditional formatting, and highly generic utility scripts — but comes with security and performance tradeoffs.

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Basic Evaluate() usage

Pass any valid FileMaker expression as a text string. Evaluate() returns the result as if the expression were in a calculation field.

FileMaker Script

// Simple example
Evaluate ( "1 + 1" )  // → 2

// Referencing a field stored in another field
Evaluate ( FormulaTable::FormulaText )

// Example formula stored in field:
// "Contacts::FirstName & " " & Contacts::LastName"

GetNthRecord: accessing other records in a calculation Text parsing: Position, Middle, Left, Right, Filter