github.com/avenga/couper@v1.12.2/docs/website/content/2.configuration/2.expressions.md (about) 1 --- 2 title: 'Expressions' 3 description: 'Basic explanation of how to use hcl expressions.' 4 --- 5 6 # Expressions 7 8 Since we use [HCL 2.0](https://github.com/hashicorp/hcl/tree/hcl2#information-model-and-syntax) for our configuration, we are able to use attribute values as expression. 9 10 ```hcl 11 // Arithmetic with literals and application-provided variables. 12 sum = 1 + addend 13 14 // String interpolation and templates. 15 message = "Hello, ${name}!" 16 17 // Application-provided functions. 18 shouty_message = upper(message) 19 ``` 20 21 See [functions](/configuration/functions).