Formula language

This page is the reference for Quotometry’s formula language, which you use for the few pricing rules that a number in a form cannot express: “double the setup charge under five pieces”, “add a handling fee that scales with the bounding box”, “send anything over 400 mm tall to review”.

Formulas are written in the configuration editor, type-checked when you save, and compiled once when the configuration is published. A configuration that refers to a variable that does not exist cannot be published, so the mistake is caught at your desk, not in front of a buyer.

Before you begin

• A plan that includes formulas.
• A draft configuration to edit, and a part to try it on in the sample-quote panel.

The language

A subset of CEL and nothing more. There are no loops, no I/O, no clock and no randomness. An expression is at most 4 KiB, nests at most 32 levels deep, and runs on a budget of 10 000 operations; a formula that would not finish is refused rather than run.

• Arithmetic + - * / %, comparison < <= > >= == !=, logic && || ! and the ternary cond ? a : b.
• Membership: sel.material in ["petg", "asa"]. in is an operator, not a function.
• Numbers are exact, and equality on them is exact. Strings have no escape sequences.
• Division by zero, NaN and infinity are errors, not values.

Functions

Function	Returns
min(a, b, …), max(a, b, …)	The smallest or largest argument.
abs(x)	The absolute value.
ceil(x), floor(x)	x rounded up or down to a whole number.
round(x[, places])	x rounded to a whole number, or to places decimal places.
sqrt(x), ln(x), exp(x), pow(a, b)	Square root, natural logarithm, e to the power x, a to the power b.
clamp(x, low, high)	x, limited to the range from low to high.
interp(x, table.name)	Linear interpolation between the rows of a table you defined in the configuration.
tier(x, table.name)	Step lookup: the value of the last row whose threshold x has reached.

Variables

Every variable below is available to every line-level formula:

Group	Variables
Quantity	qty
Geometry	part.volume_cm3 part.area_cm2 part.bbox.x part.bbox.y part.bbox.z (mm) part.bbox_volume_cm3 part.hull_volume_cm3 part.complexity part.mass_g
Estimate	est.material_g est.support_g est.machine_h est.labour_h est.batches est.parts_per_batch est.confidence
Cost	cost.material cost.machine cost.labour cost.subtotal
Price	price.before: the computed unit price, in the hooks that adjust it

Each configuration adds its own:

• sel.<option id>: what the buyer chose. A dropdown is text, a toggle is a boolean, and a count or a slider is a number, so sel.infill > 40 and sel.material == "petg" type-check only where they make sense.
• const.<name> and table.<name>: your own constants and lookup tables.

cost.* variables are costs, not prices. They exist so you can write a rule about your own economics; nothing computed from them reaches a buyer except as part of the final price.

Where formulas hook in

Hook	Type	What it does
adjust_unit_price	number	Multiplies the computed unit price. 1 changes nothing.
override_unit_price	number	Replaces the unit price outright. Use it sparingly: everything before it still runs.
extra_lines.<id>	number	Adds a priced line with that id, for the whole line rather than per piece. The buyer sees it if your visibility settings allow.
Option charges	number	A charge computed instead of a fixed amount.
Review rules	boolean	true sends the line to a person at the shop.

Cookbook

A setup surcharge that fades out with quantity

adjust_unit_price:  qty < 5 ? 1.35 : qty < 20 ? 1.15 : 1.0

A handling fee that depends on the part’s footprint

extra_lines.handling:  max(2.50, part.bbox.x * part.bbox.y / 10000 * 3.00)

Charge more for a material you dislike running

adjust_unit_price:  sel.material in ["tpu", "pc"] ? 1.25 : 1.0

A discount table you can edit without touching the formula

Define a table volume_discount with the rows (10, 0.95), (50, 0.90) and (200, 0.85), then:

adjust_unit_price:  tier(qty, table.volume_discount)

tier steps: 49 pieces get 0.95 and 50 get 0.90. Use interp when you want the value to slide smoothly between rows instead.

Send tall, thin parts to a person

review rule:  part.bbox.z > 400 && part.bbox.x < 60 && part.bbox.y < 60

Recover a fixed cost per batch rather than per part

An extra line is an amount for the whole line, so charge the batch cost once per batch:

extra_lines.batch_setup:  est.batches * 8.00

Refuse to price a part automatically when the estimate is uncertain

review rule:  est.confidence < 0.6

Test a formula before anyone sees it

The configuration editor’s sample-quote panel prices a real part against your draft on every change. On plans that include it, the backtest re-prices up to your last 500 quote lines with the draft and shows which ones move and by how much. Write the formula, watch the number, then publish.

Next steps

• Simulator and golden parts: check a draft against the prices you know are right.
• Drafts, versions and publishing: what happens when you publish.
• Errors: formula_error and the other line-state reasons.