Let() with multiple variable declarations

Beginner

Master multi-variable Let() to write complex calculations as readable, step-by-step derivations where each variable builds on the previous.

What you'll learn

How to declare multiple variables in a single Let()
How later variables can reference earlier ones in the list
How to stage a multi-step transformation using Let() variables
How to name variables for maximum readability

Let() can declare any number of named variables in its first argument, and each variable can reference variables declared before it in the list. This transforms even the most tangled calculation into a sequence of named, comprehensible steps -- the same pattern used in functional programming languages. Mastering multi-variable Let() is the single biggest improvement most FileMaker developers can make to their calculation quality.

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Multi-variable Let() syntax

Wrap multiple variable assignments in square brackets, separated by semicolons. Each assignment is name = expression.

FileMaker Script

Let ( [
  fullName    = Contacts::FirstName & " " & Contacts::LastName ;
  initials    = Left ( Contacts::FirstName ; 1 ) & Left ( Contacts::LastName ; 1 ) ;
  displayName = If ( Length ( fullName ) > 30 ; initials ; fullName )
] ;
  displayName
)

Middle(), Left(), Right() complex parsing GetValue() and ValueCount() patterns