Add Printer to reflect Constant.show

We can either print the structure with the pattern or the code like representation of the value.

Author: nicolasstucki

compiler/src/scala/quoted/runtime/impl/QuotesImpl.scala

@@ -2178,7 +2178,7 @@ class QuotesImpl private (using val ctx: Context) extends Quotes, QuoteUnpickler
     given ConstantMethods: ConstantMethods with
       extension (self: Constant)
         def value: Any = self.value
-        def show: String = Extractors.showConstant(using QuotesImpl.this)(self)
+        def show(using printer: Printer[Constant]): String = printer.show(self)
       end extension
     end ConstantMethods
 
@@ -2714,6 +2714,13 @@ class QuotesImpl private (using val ctx: Context) extends Quotes, QuoteUnpickler
         def show(tpe: TypeRepr): String =
           Extractors.showType(using QuotesImpl.this)(tpe)
 
+      lazy val ConstantCode: Printer[Constant] = new Printer[Constant]:
+        def show(const: Constant): String = const.show
+
+      lazy val ConstantStructure: Printer[Constant] = new Printer[Constant]:
+        def show(const: Constant): String =
+          Extractors.showConstant(using QuotesImpl.this)(const)
+
     end Printer
   end reflect
 

library/src/scala/quoted/Quotes.scala

@@ -2889,7 +2889,7 @@ trait Quotes { self: runtime.QuoteUnpickler & runtime.QuoteMatching =>
         def value: Any
 
         /** Shows the constant as a String */
-        def show: String
+        def show(using Printer[Constant]): String
 
       end extension
     }
@@ -4041,6 +4041,9 @@ trait Quotes { self: runtime.QuoteUnpickler & runtime.QuoteMatching =>
     /** Default pinter for `TypeRepr` used when calling `tpe.show` */
     given TypeReprPrinter: Printer[TypeRepr] = Printer.TypeReprCode
 
+    /** Default pinter for `Constant` used when calling `const.show` */
+    given ConstantPrinter: Printer[Constant] = Printer.ConstantCode
+
     /** Module object of `type Printer`.
      *  Contains custom printers such as `TreeCode`, `TreeAnsiCode`, `TreeCases`, `TypeReprCode`, ..., `SymbolFullName` and `FlagsCombination`.
      */
@@ -4080,6 +4083,11 @@ trait Quotes { self: runtime.QuoteUnpickler & runtime.QuoteMatching =>
        */
       def TypeReprStructure: Printer[TypeRepr]
 
+      /** Prints the constant in source code. */
+      def ConstantCode: Printer[Constant]
+
+      /** Prints a pattern like representation of the `Constant`. */
+      def ConstantStructure: Printer[Constant]
     }
 
   }

scala3doc/src/dotty/dokka/tasty/BasicSupport.scala

@@ -18,22 +18,15 @@ trait BasicSupport:
     val params = annotTerm match
       case Apply(target, appliedWith) => {
         appliedWith.flatMap {
-          case Literal(constant) => Some(Annotation.PrimitiveParameter(None, constant.value match {
-            case s: String => "\"" + s"$s" + "\""
-            case other => other.toString()
-          }))
-          case NamedArg(name, Literal(constant)) => Some(Annotation.PrimitiveParameter(Some(name), constant.value match
-            case s: String => "\"" + s"$s" + "\""
-            case other => other.toString()
-          ))
+          case Literal(constant) => Some(Annotation.PrimitiveParameter(None, constant.show))
+          case NamedArg(name, Literal(constant)) => Some(Annotation.PrimitiveParameter(Some(name), constant.show))
           case x @ Select(qual, name) => None
           case other => Some(Annotation.UnresolvedParameter(None, other.show))
         }
       }
 
     Annotation(dri, params)
 
-
   extension (sym: Symbol)
     def documentation = sym.docstring match
       case Some(docstring) =>

scala3doc/src/dotty/dokka/tasty/TypesSupport.scala

@@ -84,10 +84,7 @@ trait TypesSupport:
       case AndType(left, right) => inner(left) ++ texts(" & ") ++ inner(right)
       case ByNameType(tpe) => text("=> ") :: inner(tpe)
       case ConstantType(constant) =>
-        texts(constant.value match
-          case c: Char => s"'$c'"
-          case other => other.toString
-        )
+        texts(constant.show)
       case ThisType(tpe) => inner(tpe)
       case AnnotatedType(AppliedType(_, Seq(tpe)), annotation) if isRepeated(annotation) =>
         inner(tpe) :+ text("*")