Write a code expression

Version

3.x

Updated

2 Aug 2026

View markdown

Audience: store admins · Scope: the Code calculation style · Last reviewed: 2026-07-21

What this does — Lets you type a pricing formula instead of assembling it from drag-and-drop chips. It is the same engine as the Formula style with a different way in: quicker for short arithmetic, and the only style that can read the running total of the configuration.

Despite the name, this is not programming. An expression is a line of school arithmetic — numbers, + - * /, brackets — where some of the numbers are written as keywords that CBX replaces with live values from the customer's configuration.

Before you start

• Read where prices come from and build a calculation — a code expression is one of the three calculation styles, and is created, saved and attached exactly like the others.
• Have the IDs of the questions and calculations you want to read. Question IDs appear next to the title in the placeholder drop-downs (Motor Power (ID: 2)) and in the questions list; calculation IDs are in the Calculations list.
• If the formula only reads questions the customer types into, you may not need any keyword at all — the A–D placeholders will do.

Steps

1. Go to Calculations, click Add, name the calculation, choose the product and pick the style Code.

2. Bind up to four questions to the placeholders A, B, C and D using Question for placeholder A … D. Leave the rest on Not used.

   

3. Type the expression in the Code box. The screenshot's formula is an area price in square metres: two questions in millimetres bound to A and B, then

   A * B / 1000000 * 65

4. Save, then attach it — nothing is calculated until the calculation is set as a question's or answer's Price Calculation (or Recurring Price / Weight Calculation), used as a calculated minimum/maximum, or referenced from a rule or another calculation. See build a calculation.

5. Open the configurator and check the number against a calculator. Always check a code expression live — it is accepted as typed, without a preview.

The three rules that break formulas

The editor's own Notes section states them, and almost every broken expression breaks one:

1. A dot is the decimal mark. 0.25, never 0,25.
2. No thousands separators. 1000000, never 1 000 000 or 1,000,000.
3. A space before and after every placeholder and keyword. A * B, not A*B. The values are substituted textually, so a missing space glues two numbers together.

Placeholders accept numbers only. Bind them to text-field questions with numbers-only validation, and an empty field counts as 0.

Keyword reference

Every keyword is replaced with a live value from the configuration the customer is building.

Keyword	Value it produces
Total	The running total of the configuration. Once per product only
TotalRecurring	The running recurring total. Once per product only
QuestionPrice(id)	The current price of that question
QuestionPriceRecurring(id)	The current recurring price of that question
QuestionSelection(id)	What the customer typed into that question — numbers only; empty counts as 0
QuestionProperty(id.path)	Any attribute of that question or its selected answer (see below)
Calculation(id)	The result of another calculation of this product

QuestionSelection(id) does exactly what an A–D placeholder does. Use the placeholders while you have four or fewer questions — they read better — and fall back to the keyword beyond that.

QuestionProperty paths

Write the question ID, a dot, then the attribute. Using question 22 as the example:

Path	What it reads
QuestionProperty(22.selectedAnswer.weight)	The weight of the answer the customer picked
QuestionProperty(22.question_custom_1) … _4	The question's own custom fields (question screen → Custom Fields)
QuestionProperty(22.selectedAnswer.assignment_custom_1) … _4	The selected answer's custom fields, from the answer screen
QuestionProperty(22.selectedAnswer.option_custom_1) … _4	The selected answer's global custom fields, from the answer screen

Custom fields are how you attach your own numbers — a material factor, a supplier code, a labour rate — to a question or an answer and price from them, without inventing a hidden question.

Reading the question you are attached to

RegardingQuestion means "whichever question or answer this calculation is attached to". A calculation written with it can be attached to many questions at once and always reads its own:

Keyword	What it reads
RegardingQuestion(question_custom_1)	Custom field 1 of the question using this calculation
RegardingQuestion(regardingAnswer.weight)	The weight of the answer using this calculation
RegardingQuestion(regardingAnswer.assignment_custom_1)	Custom field 1 of the answer using this calculation

This is what turns ten near-identical formulas into one.

Worked examples

Area price. Width and Height are text fields in millimetres, bound to A and B; the rate is €65 per square metre:

A * B / 1000000 * 65

A percentage of the whole configuration. Attach to the question that should carry the surcharge — an insurance or service option, for instance:

Total * .25

The demo store's Phone with Contract product does exactly this, and the recurring twin TotalRecurring * .25 for the monthly side. Remember the once-per-product limit: only one calculation in a product may read Total.

Price from a custom field. The material factor sits in custom field 1 of each answer of question 30, and the base rate comes from a text field bound to A:

A * QuestionProperty(30.selectedAnswer.assignment_custom_1)

Composing calculations. Keep pieces small and readable, then combine them:

Calculation(14) + Calculation(15)

Reusable per-question rate. One calculation attached to every answer that carries a rate in its custom field 1, multiplied by the entry in A:

A * RegardingQuestion(regardingAnswer.assignment_custom_1)

Good to know

• Code and Formula are equally powerful for arithmetic — pick whichever you will still understand in six months. The one thing only Code can do is read Total / TotalRecurring.
• Compose, don't inflate. Several small named calculations referencing each other with Calculation(id) stay debuggable; one long line does not.
• Watch the ID. Keywords address questions by number, so a formula that reads QuestionProperty(30…) breaks silently if question 30 is deleted. The calculation edit form lists where a calculation is in use; there is no equivalent warning in the other direction.
• Author in the base currency and ignore tax. Currency conversion, customer-group overrides and tax are applied on top of the result.
• Copying a product copies its code calculations and re-points every reference.

Troubleshooting

• The price is 0 or blank. A placeholder is bound to a question the customer hasn't reached, or to one that isn't numbers-only. Empty entries count as 0, and anything multiplied by 0 is 0.
• The result is wildly wrong. Look for a missing space around a placeholder, a comma used as a decimal mark, or a thousands separator.
• Total gives a strange number. Check that no second calculation in the same product also uses Total — it may be used only once per product. Also remember it is the total so far, so a percentage-of-total surcharge should sit on a late page.
• Nothing calculates at all. The calculation isn't attached yet. Creating it is only half the job — see step 4.