# How to define conditional rules
**URL:** https://discourse.dry-rb.org/t/how-to-define-conditional-rules/1292
**Category:** dry-validation
**Created:** [June 30, 2021, 1:54pm UTC](https://discourse.dry-rb.org/t/how-to-define-conditional-rules/1292 "2021-06-30T13:54:52Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@morgoth](https://discourse.dry-rb.org/u/morgoth)
#### Post date: [June 30, 2021, 1:54pm UTC](https://discourse.dry-rb.org/t/how-to-define-conditional-rules/1292/1 "2021-06-30T13:54:52Z")
I would like to “run” a rule only when the attribute/key is truthy, so something like:
```auto
class Search < Dry::Validation::Contract
params do
optional(:email).value(:string)
end
rule(:email) do
key? && SomeLogicForValidation(value)
end
end
```
Here I would like to get rid of “key?” somehow.
When I try with early return like `return unless key?` I’m getting an error: `LocalJumpError`.
Is it already possible somehow?
---
### Author:  [@alassek](https://discourse.dry-rb.org/u/alassek)
#### Post date: [June 30, 2021, 5:46pm UTC](https://discourse.dry-rb.org/t/how-to-define-conditional-rules/1292/2 "2021-06-30T17:46:51Z")
There’s [an open issue](https://github.com/dry-rb/dry-validation/issues/678) with a potential new API for this, but for now you will have to rely on guard clauses.
The LocalJumpError happened because Procs don’t trap `return`, and the code is not running inside a method. Inside a proc you may use `next` to achieve the same result:
```ruby
next unless key?
```
The difference between Proc and Lambda [can be confusing](https://medium.com/rubycademy/procs-and-lambdas-46433b93080d) but they each serve a different purpose, and work slightly differently because of that.
FWIW I usually write this kind of rule as
```ruby
rule :email do
SomeLogicForValidation(value) if key?
end
```
which honestly doesn’t seem that bad
---
### Author:  [@morgoth](https://discourse.dry-rb.org/u/morgoth)
#### Post date: [July 1, 2021, 6:42am UTC](https://discourse.dry-rb.org/t/how-to-define-conditional-rules/1292/3 "2021-07-01T06:42:05Z")
Thank you. `next` works fine.
I added a bit simplified example. In my case the validation is few lines of codes, so the early return makes it much nicer.
Proposition with adding a guard to DSL looks nice.