# Defining a pattern as string for use in hydra
**URL:** https://uzu.lurk.org/t/defining-a-pattern-as-string-for-use-in-hydra/6045
**Category:** Strudel
**Tags:** questions
**Created:** [26 December 2025 13:18 UTC](https://uzu.lurk.org/t/defining-a-pattern-as-string-for-use-in-hydra/6045 "2025-12-26T13:18:52Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@nscott32](https://uzu.lurk.org/u/nscott32)
#### Post date: [26 December 2025 13:18 UTC](https://uzu.lurk.org/t/defining-a-pattern-as-string-for-use-in-hydra/6045/1 "2025-12-26T13:18:52Z")
I would like to be able to define a pattern as a string in one of the format accepted by tidal (note, struct, etc) so that I can then process it and reuse it in hydra.
For example I have a note pattern with silences:
```haskell
"[0 - - 0] [- 3] [- 3 - -] [-2]"
```
I want to use it in hydra `kaleid` function using `H`, however the `-` aren’t correct values for `kaleid` and this triggers errors in the console.I would like to programatically replace values like `-` =\> `0` before feeding it to `H` in hydra.
Is that possible?
The problem I am facing currently is that I can’t call `.replaceAll` on the string as they seem to all be preprocessed and converted to an object.
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### Author:  [@firolightfog](https://uzu.lurk.org/u/firolightfog)
#### Post date: [26 January 2026 08:30 UTC](https://uzu.lurk.org/t/defining-a-pattern-as-string-for-use-in-hydra/6045/2 "2026-01-26T08:30:32Z")
Have you managed to find a way? I’m also interested…