For meta programming in Scala using the Scalameta library
This tag is for questions relating to the Scalameta library for Scala.
Questions tagged [scalameta]
66 questions
13
votes
3 answers
Scala tool to remove all unused code
I am writing a Scala plugin for an editor I use that would highlight all unused code paths (could be unused defs, vals, classes and implicits), and give the user an option to yank them out of the .scala file.
How can I do this? To simplify the…
pathikrit
- 32,469
- 37
- 142
- 221
10
votes
1 answer
Use Scala macros to generate methods
I want to generate aliases of methods using annotation macros in Scala 2.11+. I am not even sure that is even possible. If yes, how?
Example - Given this below, I want the annotation macros to expand into
class Socket {
@alias(aliases = Seq("!",…
pathikrit
- 32,469
- 37
- 142
- 221
7
votes
1 answer
Difference Between Scala Expressions
Up until recently it was my understanding that two Scala statements below were interchangeable.
expr.op(arg1, arg2,...)
expr op (arg1, arg2,...)
But I've playing around with scala meta, looked at the resulting AST they…
Sledge
- 178
- 13
6
votes
1 answer
new-style ("inline") macros require scala.meta
I just updated to scala meta 2.0.0-M1 and with the latest scala 2.12.3 and now macros no longer compile. The only change i made was to change the meta version from 1.8.0 to 2.0.0-M1.
ERROR: new-style ("inline") macros require scala.meta
Does anybody…
Will
- 151
- 4
6
votes
1 answer
Scala recursive macro?
I was wondering whether Scala supports recursive macro expansion e.g. I am trying to write a lens library with a lensing macro that does this:
case class C(d: Int)
case class B(c: C)
case class A(b: B)
val a = A(B(C(10))
val aa = lens(a)(_.b.c.d)(_…
pathikrit
- 32,469
- 37
- 142
- 221
5
votes
1 answer
automatically generate case object for case class
How can I have the scala compiler automatically generate the case object?
// Pizza class
class Pizza (val crust_type: String)
// companion object
object Pizza {
val crustType = "crust_type"
}
Desired properties for case object
for each…
Georg Heiler
- 16,916
- 36
- 162
- 292
5
votes
1 answer
Scala Macro: Create new classes with Option types
I want to write a macro given this:
@MetaRest case class User(
@get id : Int,
@get @post @patch name : String,
@get @post email : String,
registeredOn :…
pathikrit
- 32,469
- 37
- 142
- 221
3
votes
0 answers
Relationship between ScalaMeta, ScalaFix, and SemanticDB
I have the following information:
Scalameta: has the ability to produce ASTs from a source file
SemanticDB: Contains information about symbols from a parsed source
file
ScalaFix: is based on ScalaMeta and SemanticDB so it has the ability to access…
Gakuo
- 845
- 6
- 26
3
votes
1 answer
Code generated with scalameta is not recognized by intellij
I'm trying to create a scalameta annotation, that will define a new case class inside of an existing object.
my goal is to transform:
object MyObj {
case class A()
}
into:
object MyObj {
case class A()
case class B(b: Int, bb: Int)
}
for…
lev
- 3,986
- 4
- 33
- 46
3
votes
0 answers
How to run the Defn generated by the scalameta
I am playing with Scalameta. this is my build.sbt
lazy val commonSettings = Seq(
scalaVersion := "2.12.3"
)
lazy val macroProject = (project in file("MacroProject")).settings(
commonSettings,
name := "MacroProject",
libraryDependencies…
Knows Not Much
- 30,395
- 60
- 197
- 373
3
votes
1 answer
Using code generation (like Scala Meta) to scrape boilerplate
I use Shapeless's tagged types to get nice typesafe primitives to pass through my business logic. Defining these types started with a simple:
sealed trait MyTaggedStringTag
type MyTaggedString = String @@ MyTaggedStringTag
But I've added a good bit…
acjay
- 34,571
- 6
- 57
- 100
3
votes
1 answer
Scalameta Decl.Def not works on a trait def method
I'm use Scalameta(v1.8.0) annotation to a def declaration:
trait MyTrait {
@MyDeclDef
def f2(): Int
}
The annotation class defined just return input, as this:
import scala.meta._
class MyDeclDef extends scala.annotation.StaticAnnotation {
…
LoranceChen
- 2,453
- 2
- 22
- 48
3
votes
1 answer
Scalameta: Identify particular annotations
I want to auto-generate REST API models in Scala using scalameta annotation macros. Specifically, given:
@Resource case class User(
@get id : Int,
@get @post @patch name : String,
@get @post email :…
pathikrit
- 32,469
- 37
- 142
- 221
2
votes
1 answer
Scalafix: resolving object apply method
I have an object with some apply method defined and then use it
object Ob {
def apply(i: Int) = ()
def apply(s: String) = ()
}
object Use {
def someMethod(i: Int) = ()
Ob(1)
someMethod(1)
}
When using scalafix/scalameta, I'm unable to…
Jacob Wang
- 4,411
- 5
- 29
- 43
2
votes
2 answers
Scala conditional compilation
I'm writing a Scala program and I want it to work with two version of a big library.
This big library's version 2 changes the API very slightly (only one class constructor signature has an extra parameter).
// Lib v1
class APIClass(a: String,…
sscarduzio
- 5,938
- 5
- 42
- 54