# Functions & Operators

Documint uses an enhanced version of [Handlebars](https://handlebarsjs.com/guide/#what-is-handlebars) as its templating engine. This means all valid Handlebars syntax is valid Documint syntax. Below is a list of custom functions that can be used in your Documint templates. 

#### Combining Functions

You can combine functions by wrapping the inner function in parenthesis.

```handlebars
//Example
{{$multiply ($add amount_1 amount_2) ($add amount_3 amount_4)}}
```

Here we're using the `$add` function to sum two sets of values then multiplying them together. Functions in parenthesis will be evaluated first and returned to its parent function. 

## General

### $calc

The $calc function is a powerful expression evaluator that enables complex calculations, string manipulations, array operations, and provides a secure sandbox environment within your templates.

{% content-ref url="../../legacy-documentation/data-and-variables/functions/calc" %}
[calc](https://docs.documint.me/legacy-documentation/data-and-variables/functions/calc)
{% endcontent-ref %}

## Math

{% content-ref url="functions-and-operators/math/usdadd" %}
[usdadd](https://docs.documint.me/templates/working-with-dynamic-data/functions-and-operators/math/usdadd)
{% endcontent-ref %}

{% content-ref url="functions-and-operators/math/usdsubtract" %}
[usdsubtract](https://docs.documint.me/templates/working-with-dynamic-data/functions-and-operators/math/usdsubtract)
{% endcontent-ref %}

{% content-ref url="functions-and-operators/math/usdmultiply" %}
[usdmultiply](https://docs.documint.me/templates/working-with-dynamic-data/functions-and-operators/math/usdmultiply)
{% endcontent-ref %}

{% content-ref url="functions-and-operators/math/usddivide" %}
[usddivide](https://docs.documint.me/templates/working-with-dynamic-data/functions-and-operators/math/usddivide)
{% endcontent-ref %}

{% content-ref url="functions-and-operators/math/usdsum" %}
[usdsum](https://docs.documint.me/templates/working-with-dynamic-data/functions-and-operators/math/usdsum)
{% endcontent-ref %}

{% content-ref url="functions-and-operators/math/usdmin" %}
[usdmin](https://docs.documint.me/templates/working-with-dynamic-data/functions-and-operators/math/usdmin)
{% endcontent-ref %}

{% content-ref url="functions-and-operators/math/usdmax" %}
[usdmax](https://docs.documint.me/templates/working-with-dynamic-data/functions-and-operators/math/usdmax)
{% endcontent-ref %}

{% content-ref url="functions-and-operators/math/usdmean" %}
[usdmean](https://docs.documint.me/templates/working-with-dynamic-data/functions-and-operators/math/usdmean)
{% endcontent-ref %}

{% content-ref url="functions-and-operators/math/usdround" %}
[usdround](https://docs.documint.me/templates/working-with-dynamic-data/functions-and-operators/math/usdround)
{% endcontent-ref %}

{% content-ref url="functions-and-operators/math/usdfloor" %}
[usdfloor](https://docs.documint.me/templates/working-with-dynamic-data/functions-and-operators/math/usdfloor)
{% endcontent-ref %}

{% content-ref url="functions-and-operators/math/usdceil" %}
[usdceil](https://docs.documint.me/templates/working-with-dynamic-data/functions-and-operators/math/usdceil)
{% endcontent-ref %}

## List/Arrays

{% content-ref url="functions-and-operators/list-arrays/each" %}
[each](https://docs.documint.me/templates/working-with-dynamic-data/functions-and-operators/list-arrays/each)
{% endcontent-ref %}

{% content-ref url="functions-and-operators/list-arrays/usdfilter" %}
[usdfilter](https://docs.documint.me/templates/working-with-dynamic-data/functions-and-operators/list-arrays/usdfilter)
{% endcontent-ref %}

{% content-ref url="functions-and-operators/list-arrays/usdgroup" %}
[usdgroup](https://docs.documint.me/templates/working-with-dynamic-data/functions-and-operators/list-arrays/usdgroup)
{% endcontent-ref %}

{% content-ref url="functions-and-operators/list-arrays/usdjoin" %}
[usdjoin](https://docs.documint.me/templates/working-with-dynamic-data/functions-and-operators/list-arrays/usdjoin)
{% endcontent-ref %}

## Helpers

{% content-ref url="functions-and-operators/helpers/usdextname" %}
[usdextname](https://docs.documint.me/templates/working-with-dynamic-data/functions-and-operators/helpers/usdextname)
{% endcontent-ref %}

{% content-ref url="functions-and-operators/helpers/usdinspect" %}
[usdinspect](https://docs.documint.me/templates/working-with-dynamic-data/functions-and-operators/helpers/usdinspect)
{% endcontent-ref %}

## Content

{% content-ref url="functions-and-operators/content/usdlink" %}
[usdlink](https://docs.documint.me/templates/working-with-dynamic-data/functions-and-operators/content/usdlink)
{% endcontent-ref %}

{% content-ref url="functions-and-operators/content/usdmd" %}
[usdmd](https://docs.documint.me/templates/working-with-dynamic-data/functions-and-operators/content/usdmd)
{% endcontent-ref %}