Authoring guidelines: preloaded

content/recipes/authoring/kata-snippets/preloaded.md

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 # Writing Preloaded Code
 
-_This page is a stub._
+The preloaded code snippet, created by the kata author or translator, can be used to reduce boilerplate code, but when used incorrectly, it can cause lots of problems. To ensure the quality of the kata, it should conform to a set of guidelines presented below.
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+This article contains a set of guidelines for kata authors and translators to create good code snippets for their kata. They were collected to help ensure that kata and translations are of sufficient quality and kata maintenance will be as easy as possible.
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+The guidelines should be used by kata authors, translators and reviewers to verify whether new content about to be introduced to Codewars is of sufficient quality. Conformance with them should be verified before a kata or translation is published by its author and approved by a reviewer.
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+Failure to comply with the below guidelines should be considered an issue to be addressed and reported as such. In case of severe violations, the affected kata or translation may be retired, moved back to beta or rejected.
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+
+## Accessibility of Preloaded Code
+
+- Preloaded Code snippet is a code, and, as such, should conform to [Codewars General Coding Guidelines](/recipes/authoring/general/).
+- **Do not put in preloaded any code which should not be called by submitted solution.** Code placed in this snippet can be called (and for some languages even modified or redefined) by submitted solution, and any data stored here can be read or modified programatically. It should not contain anything critical what would be used by tests to validate correctness of the solution.
+- **Be aware that user solution is able to read the file with preloaded snippet**. It should not contain any information which would reveal details on solution or tests, which should not be visible to the user.
+- **Do not hide useful information in preloaded.** Preloaded snippet can be use to reduce boilerplate, and its code is available to all other parts of solution. It can be tempting to put there some data or types which should be shared among user solution, sample tests, and submission tests. But remember that contents of preloaded code are not displayed anywhere in user interface and users cannot see it. This is especially problematic for users who would like to work on the kata in their local IDE, but now are missing some pieces necessary to set up their local environment. If you use preloaded part to reduce bolerplate code, consider adding necessary information also to kata description, preferrably in [language conditional block](/references/markdown/extensions/).