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Fix macro docs #8545

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merged 2 commits into from
Mar 15, 2020
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Fix macro docs #8545

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d85cb98
Update Unliftable/unlift/unliftOrError
nicolasstucki Mar 15, 2020
3941b59
Fix #8540: Add missing inline to args
nicolasstucki Mar 15, 2020
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12 changes: 6 additions & 6 deletions docs/docs/reference/metaprogramming/macros.md
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Expand Up @@ -433,7 +433,7 @@ either a constant or is a parameter that will be a constant when instantiated. T
aspect is also important for macro expansion.

To get values out of expressions containing constants `Expr` provides the method
`getValue` (or `value`). This will convert the `Expr[T]` into a `Some[T]` (or `T`) when the
`unlift` (or `unliftOrError`). This will convert the `Expr[T]` into a `Some[T]` (or `T`) when the
expression contains value. Otherwise it will retrun `None` (or emit an error).
To avoid having incidental val bindings generated by the inlining of the `def`
it is recommended to use an inline parameter. To illustrate this, consider an
Expand All @@ -442,7 +442,7 @@ implementation of the `power` function that makes use of a statically known expo
inline def power(x: Double, inline n: Int) = ${ powerCode('x, 'n) }

private def powerCode(x: Expr[Double], n: Expr[Int])(using QuoteContext): Expr[Double] =
n.getValue match
n.unlift match
case Some(m) => powerCode(x, m)
case None => '{ Math.pow($x, $y) }

Expand Down Expand Up @@ -604,7 +604,7 @@ inline method that can calculate either a value of type `Int` or a value of type
inline def defaultOf(inline str: String) <: Any = ${ defaultOfImpl('str) }

def defaultOfImpl(strExpr: Expr[String])(using QuoteContext): Expr[Any] =
strExpr.value match
strExpr.unliftOrError match
case "int" => '{1}
case "string" => '{"a"}

Expand Down Expand Up @@ -633,7 +633,7 @@ It is possible to deconstruct or extract values out of `Expr` using pattern matc
`scala.quoted` contains objects that can help extracting values from `Expr`.

* `scala.quoted.Const`/`scala.quoted.Consts`: matches an expression of a literal value (or list of values) and returns the value (or list of values).
* `scala.quoted.Value`/`scala.quoted.Values`: matches an expression of a value (or list of values) and returns the value (or list of values).
* `scala.quoted.Unlifted`: matches an expression of a value (or list of values) and returns the value (or list of values).
* `scala.quoted.Varargs`: matches an explicit sequence of expresions and returns them. These sequences are useful to get individual `Expr[T]` out of a varargs expression of type `Expr[Seq[T]]`.

These could be used in the following way to optimize any call to `sum` that has statically known values.
Expand Down Expand Up @@ -671,7 +671,7 @@ optimize {

```scala
def sum(args: Int*): Int = args.sum
inline def optimize(arg: Int): Int = ${ optimizeExpr('arg) }
inline def optimize(inline arg: Int): Int = ${ optimizeExpr('arg) }
private def optimizeExpr(body: Expr[Int])(using QuoteContext): Expr[Int] = body match {
// Match a call to sum without any arguments
case '{ sum() } => Expr(0)
Expand Down Expand Up @@ -717,7 +717,7 @@ This might be used to then perform an implicit search as in:


```scala
inline def (sc: StringContext).showMe(inline args: Any*): String = ${ showMeExpr('sc, 'args) }
inline def (inline sc: StringContext).showMe(inline args: Any*): String = ${ showMeExpr('sc, 'args) }

private def showMeExpr(sc: Expr[StringContext], argsExpr: Expr[Seq[Any]])(using qctx: QuoteContext): Expr[String] = {
argsExpr match {
Expand Down