Formula Expression Engine

LotusGen allows custom column derivations and conditional filtering through a secure AST sandbox that evaluates expressions without unsafe eval() calls.

Intra-Table Dependencies

A function column can reference any column defined above it in the table schema. The intra-table DAG automatically validates column evaluation order and rejects circular references.

Supported Syntax & Functions

Arithmetic Operators

• Addition: +
• Subtraction: -
• Multiplication: *
• Division: /
• Floor Division: //
• Modulo: %
• Power: **

Comparison Operators

• Equality: ==, !=
• Inequality: <, <=, >, >=

Logical Operators

• Conjunction: and
• Disjunction: or
• Inversion: not

Built-in Mathematical Functions

• abs(x): Absolute value
• round(x, n): Round number to n decimal places
• min(a, b): Minimum of values
• max(a, b): Maximum of values
• sqrt(x): Square root

Ternary Conditionals

Python-style inline ternary expressions are fully supported:

value_if_true if condition else value_if_false

Formula Examples

Price Calculation with Tax

round(unit_price * (1 + tax_rate), 2)

Customer Tier Segmentation

'VIP' if total_spend > 1000 else 'Regular'

Full Name Concatenation

first_name + ' ' + last_name

Conditional Row Filtering (exclude_if)

Tables support an optional exclude_if formula. When generating data, if exclude_if evaluates to True for a given row, that row is omitted from the output stream:

# Example: Exclude inactive trial users with zero activity
status == 'trial' and login_count == 0