[docs/reference] more fixes in Markdown files

[michelou]

Follow up of PR #10767.

Fixes further issues found in MarkDown files in docs/reference/, e.g,

• removed extra spaces
• corrected misspellings, etc.
• reduced line width in several code blocks (to avoid text overflow in the right margin)
• added missing link to PNG image (class hierarchy in section 6.11.1)
• added several external links (e.g. Unicode character)

PS. The result of the above changes can be viewed in the PDF document scala3_reference.pdf (736 Kb) generated with Pandoc 2.11.

[liufengyun]

LGTM, thanks @michelou 👍

added missing PNG image (class hierarchy in section 6.11.1)

Do you forget the file, I can't find it in the PR.

[liufengyun]

@nicolasstucki : Do we still support this use case? It seems to be a valid use case.

[liufengyun]

@nicolasstucki : do we still support Constant?

[michelou]

@liufengyun For some reason the PNG file explicit-nulls-type-hierarchy.png is outside the docs/reference/ directory (see images/explicit-nulls/). Before running pandoc I call a small preprocessor script which performs several transformations, e.g.

• replace internal relative links to anchors
• copy image files to the right place for pandoc

[nicolasstucki]

Yes, but that code is extremely outdated and would not compile. I would use the following version instead

---

inline def power(x: Double, n: Int): Double =
  ${ powerExpr('x, 'n) }

private def powerExpr(n: Expr[Int], x: Expr[Double])(using Quotes): Expr[Double] =
  n.value match
    case Some(m) => powerCode(x, m)
    case _ => '{ dynamicPower($x, $n) }

private def dynamicPower(x: Double, n: Int): Double =
  if n == 0 then 1.0
  else if n % 2 == 0 then dynamicPower(x * x, n / 2)
  else x * dynamicPower(x, n - 1)

This assumes a .value that maps tree nodes representing constants to their values.

---

[michelou]

@nicolasstucki Is the following self-contained code ok for you (NB. powerCode is not defined in your code) ?!

For replacement of the first code example in section "Going Further" of file metaprogramming/macro-spec.md:

import scala.quoted.Expr
import scala.quoted.Quotes

inline def power(x: Double, n: Int): Double =
  ${ powerExpr('x, 'n) }

private def powerExpr(x: Expr[Double], n: Expr[Int])(using Quotes): Expr[Double] =
  n.value match
    case Some(m) => powerExpr(x, m)
    case _ => '{ dynamicPower($x, $n) }

private def powerExpr(x: Expr[Double], n: Int)(using Quotes): Expr[Double] =
  if n == 0 then '{ 1.0 }
  else if n == 1 then x
  else if n % 2 == 0 then '{ val y = $x * $x; ${ powerExpr('y, n / 2) } }
  else '{ $x * ${ powerExpr(x, n - 1) } }

private def dynamicPower(x: Double, n: Int): Double =
  if n == 0 then 1.0
  else if n % 2 == 0 then dynamicPower(x * x, n / 2)
  else x * dynamicPower(x, n - 1)

For testing (not to be included): Main.scala

@main
def Main: Unit =
  val x = 2.0
  for n <- 1 to 10 do
    println(s"power($x, $n) = ${power(x, n)}")

PS. The paragraph directly following the above code example mentions Constant. I assume that text can be removed right ?!

[nicolasstucki]

You can replace it with

This assumes a `.value` that maps tree nodes representing constants to their values.

[nicolasstucki]

And use import scala.quoted._

[michelou]

@liufengyun addressed review comment.

[liufengyun]

Thanks @michelou 👍

[michelou]

@liufengyun Thanks. I will create an new PR with more changes, including Nicolas's suggestion (see above):

This assumes a `.value` that maps tree nodes representing constants to their values.