In Scala, quasiquotes are shipped in the official Scala distribution as part of scala-reflect.jar
Read also: http://docs.scala-lang.org/overviews/quasiquotes/intro.html
Questions tagged [scala-quasiquotes]
91 questions
1
vote
1 answer
Liftable for function literal
Is there a way to make a Liftable for a functional literal (with 2.11)? If I have
case class Validator[T](predicate: T => Boolean)
val predicate = (s: String) => s.startsWith("Hi")
then I want to be able to quasiquote predicate too:
q"new…
Marc Grue
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1
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1 answer
How to get a type in Scala AST of underscored lambda function parameter?
Not digging in details of DSL, I could write (based on that example):
def InputLine = rule { Number ~ zeroOrMore("+" ~ Number ~> ((x: Int, y: Int) => x + y)) ~ EOI }
I need to call lambda function from macro. Scala AST representation of it is as…
Alexander Myltsev
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1
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1 answer
How to pass arguments to a function of arbitrary number of parameters via macro?
I have deconstructed Function, got it vparams, and now I am able to call:
case class Action(f: Function, ts: List[TypeName]) {
def render(ruleName: String): Expr[Unit] = c.Expr[Unit](q"""
val p = ${c.prefix}
val value1 =…
Alexander Myltsev
- 459
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0
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1 answer
How to runtime compile with reflection for a class being used within another class
My code:
import scala.reflect.runtime
import scala.reflect.runtime.universe
import scala.reflect.runtime.universe._
import scala.tools.reflect.ToolBox
object Stuff {
val rm: universe.Mirror = runtime.currentMirror
val tb: ToolBox[universe.type]…
0
votes
2 answers
Scala 3 Macros: How to invoke a method obtained as a `Symbol` in a quoted code block?
In a Scala 3 macro that takes a type parameter T, you can use TypeRepr.of[T] and the new Scala 3 reflection API to explore the companionClass of T, and find the Symbol for an arbitrary method on that companion class (eg…
Roberto Tyley
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0
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1 answer
Scala 3 macros: create a new polynmorphic function using the reflect api
I intend to create the simple polymorphic function expression below using the Quotes.reflect API:
new PolyFunction {
def apply[X](a: X): X = a
}
What I have attempted is shown below with parts that I could not implement replaced by ???:
val name:…
shayan
- 1,211
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How do I ignore unused warnings in quasiquotes?
I have a macro that is using quasiquotes like:
accessor.tree match {
// FIXME: Get rid of the unused warning here.
case q"($source) => $rhs" => validate(rhs, hasSelect = false)
case t =>…
steinybot
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0
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1 answer
Using ClassSymbol in a quasiquote
I have a ClassSymbol and want to generate a zero-argument method throwing ???. Here are my attempts:
Assume that object Test is the type we have ClassSymbol of.
I.
val sym = //the ClassSymbol
val tpe = tq"$sym.type"
q"def foo(): $tpe =…
Some Name
- 8,555
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0
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1 answer
MacroAnnotation to remove annotation from method's type member
I'm learning how to write Scala Macros and wrote a macro annotation that removes an annotation from a type parameter of an annotated function. Here it is.
The annotation to remove:
class garbage extends StaticAnnotation
Implementation of macro to…
Some Name
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0
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1 answer
How to dynamically generate a type application with scala quasiquotes
I want to generate a type application so I can call a function like foo.bar[com.a.b.SomeType](baz) where com.a.b.SomeType could be any of a broad range of types. I used reflection within the macro runtime to get a reference to actual class…
Luke Eller
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0
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2 answers
How does one obtain the type of the value that an AST represents?
I’m trying to write the following:
import scala.reflect.runtime.universe._
val value: Tree = /* some AST */
val tpe = typeOf(value) // This should be the result type of the AST.
// This is pseudocode. What should
…
Dan Li
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0
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1 answer
How does one use quasiquotes to obtain the type of a value?
I’m trying to write the following:
val value: Int = 3
val tpe = typeOf(value) // This is pseudocode. What should
// actually go on this line?
q"""
type U = $tpe
val v: U = $value
"""
Essentially, I need to capture the…
Dan Li
- 866
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- 19
0
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1 answer
How can I consume a Scala macro/quasiquote for code templates?
I want to generate a bunch of objects at compile time that follow a simple pattern, so I wrote the following macro:
object MyMacro {
def readWrite[T](taName: String, readParse: String => T, label: String, format: T => String): Any = macro…
Greg
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0
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Use scala macros to copy method from class to companion object
I'll get straight to the business.
Let's say that I have the following trait definition:
trait Routable{
def routing(): String
}
And I'm defining the following class:
case class MyEvent(name: String, age: Int) extends Routable{
override…
user1396033
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0
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1 answer
What are "stats" in Scala ASTs?
In docs.scala-lang.org/overviews/quasiquotes/syntax-summary.html#definitions, I see this "variable" called $stats all over the place. What does it stand for? Is it supposed to mean "statements"? That would be slightly odd to me since you can have…
allidoiswin
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