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refined
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Make Invalid States Unrepresentable
Scala has quite good support for refined types across multiple libraries. A solution using the refined library might look something like
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Does the fthomas/refined library work differently in Scala 3?
Does the Refined library for Scala (at https://github.com/fthomas/refined; "eu.timepit" %% "refined") work in Scala 3? Does it work differently?
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Type erased on implicit evidence check
I'm trying to create a poor man version of refined types implementation with a simple validation of string content and check the return type via Implicit evidence on another function. It seems that the type got erased after it got returned from the check
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Design by contract - Preconditions and Postconditions - I'm really amazed with Scala.
Scala likes to do design-by-contract on the type level. You encode your pre- and post- conditions into types. Libraries like iron (scala 3) https://github.com/Iltotore/iron and refined (scala 2) https://github.com/fthomas/refined allow you to do all that without throwing any exceptions and they can even enforce some simple predicates at compile time.
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Restrict uses of annotation in Scala
Annotation is not the only way (and probably not the best IMHO) to do refined types. You might be interested in Iron in Scala 3 or Refined in Scala 2/3.
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Cross-Training to Ada - which are the best languages to begin from?
I think the way you model problems in Ada is superficially similar to refined types you find in some functional languages (e.g. Scala).
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Can types replace validation?
In one respect, nothing. You’re right. Even given refinement types as in Haskell or Scala, there is indeed a necessarily-partial function (refineV in Scala) to refine a value to its refinement type.
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Help me break the fourth wall
Perhaps refined would help you? It lets you set constraints (i.e. "rules") for values / types. You get compile-time enforcement for constants and fallible methods for runtime values (i.e. Either[Error, RefinedValue]).
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Simple, Naïve, and Wrong: More than you wanted to know about Scala Case Classes
This is more or less how derivation works when you want to use something like Refined types (it exposes Validate[Type, Refinement] typeclass if I remember correctly). Enumeratum exposes Enum[A], and newtypes expose Coercible[From, To].
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Opinions on implementing traits for validation with the help of a companion object
You will probably be interested into Iron or Refined.
Rapture
We haven't tracked posts mentioning Rapture yet.
Tracking mentions began in Dec 2020.
What are some alternatives?
Shapeless - Generic programming for Scala
better-files - Simple, safe and intuitive Scala I/O
Records for Scala - Labeled records for Scala based on structural refinement types and macros.
Play monadic actions - A simple scala DSL to allow clean and monadic style for Play! Actions
Cassovary - Cassovary is a simple big graph processing library for the JVM
scribe - The fastest logging library in the world. Built from scratch in Scala and programmatically configurable.
Hamsters - A mini Scala utility library
Scalaz - Principled Functional Programming in Scala
ScalaTest - A testing tool for Scala and Java developers
Ammonite-Ops - Scala Scripting
Twitter Util - Wonderful reusable code from Twitter