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| 1 | +package dotty.tools.dotc |
| 2 | +package core |
| 3 | + |
| 4 | +import annotation.tailrec |
| 5 | +import Symbols._ |
| 6 | +import Contexts._, Names._, Phases._, printing.Texts._, printing.Printer |
| 7 | +import util.Spans.Span, util.SourcePosition |
| 8 | +import collection.mutable.ListBuffer |
| 9 | +import dotty.tools.dotc.transform.MegaPhase |
| 10 | +import ast.tpd._ |
| 11 | +import scala.language.implicitConversions |
| 12 | +import printing.Formatting._ |
| 13 | + |
| 14 | +/** This object provides useful conversions and extension methods for types defined elsewhere */ |
| 15 | +object DecoratorsX { |
| 16 | + |
| 17 | + /** Turns Strings into PreNames, adding toType/TermName methods */ |
| 18 | + class StringPreName(s: String) extends AnyVal with PreName { |
| 19 | + def toTypeName: TypeName = typeName(s) |
| 20 | + def toTermName: TermName = termName(s) |
| 21 | + def toText(printer: Printer): Text = Str(s) |
| 22 | + } |
| 23 | + implied for Conversion[String, StringPreName] = new StringPreName(_) |
| 24 | + |
| 25 | + final val MaxFilterRecursions = 1000 |
| 26 | + |
| 27 | + implied { |
| 28 | + def (s: String) splitWhere (f: Char => Boolean, doDropIndex: Boolean): Option[(String, String)] = { |
| 29 | + def splitAt(idx: Int, doDropIndex: Boolean): Option[(String, String)] = |
| 30 | + if (idx == -1) None |
| 31 | + else Some((s.take(idx), s.drop(if (doDropIndex) idx + 1 else idx))) |
| 32 | + |
| 33 | + splitAt(s.indexWhere(f), doDropIndex) |
| 34 | + } |
| 35 | + |
| 36 | + /** Implements a findSymbol method on iterators of Symbols that |
| 37 | + * works like find but avoids Option, replacing None with NoSymbol. |
| 38 | + */ |
| 39 | + def (it: Iterator[Symbol]) findSymbol(p: Symbol => Boolean): Symbol = { |
| 40 | + while (it.hasNext) { |
| 41 | + val sym = it.next() |
| 42 | + if (p(sym)) return sym |
| 43 | + } |
| 44 | + NoSymbol |
| 45 | + } |
| 46 | + |
| 47 | + def (xs: List[T]) mapconserve [T, U] (f: T => U): List[U] = { |
| 48 | + @tailrec |
| 49 | + def loop(mapped: ListBuffer[U], unchanged: List[U], pending: List[T]): List[U] = |
| 50 | + if (pending.isEmpty) { |
| 51 | + if (mapped eq null) unchanged |
| 52 | + else mapped.prependToList(unchanged) |
| 53 | + } else { |
| 54 | + val head0 = pending.head |
| 55 | + val head1 = f(head0) |
| 56 | + |
| 57 | + if (head1.asInstanceOf[AnyRef] eq head0.asInstanceOf[AnyRef]) |
| 58 | + loop(mapped, unchanged, pending.tail) |
| 59 | + else { |
| 60 | + val b = if (mapped eq null) new ListBuffer[U] else mapped |
| 61 | + var xc = unchanged |
| 62 | + while (xc ne pending) { |
| 63 | + b += xc.head |
| 64 | + xc = xc.tail |
| 65 | + } |
| 66 | + b += head1 |
| 67 | + val tail0 = pending.tail |
| 68 | + loop(b, tail0.asInstanceOf[List[U]], tail0) |
| 69 | + } |
| 70 | + } |
| 71 | + loop(null, xs.asInstanceOf[List[U]], xs) |
| 72 | + } |
| 73 | + |
| 74 | + /** Like `xs filter p` but returns list `xs` itself - instead of a copy - |
| 75 | + * if `p` is true for all elements and `xs` is not longer |
| 76 | + * than `MaxFilterRecursions`. |
| 77 | + */ |
| 78 | + def (xs: List[T]) filterConserve [T] (p: T => Boolean): List[T] = { |
| 79 | + def loop(xs: List[T], nrec: Int): List[T] = xs match { |
| 80 | + case Nil => xs |
| 81 | + case x :: xs1 => |
| 82 | + if (nrec < MaxFilterRecursions) { |
| 83 | + val ys1 = loop(xs1, nrec + 1) |
| 84 | + if (p(x)) |
| 85 | + if (ys1 eq xs1) xs else x :: ys1 |
| 86 | + else |
| 87 | + ys1 |
| 88 | + } else xs filter p |
| 89 | + } |
| 90 | + loop(xs, 0) |
| 91 | + } |
| 92 | + |
| 93 | + /** Like `(xs, ys).zipped.map(f)`, but returns list `xs` itself |
| 94 | + * - instead of a copy - if function `f` maps all elements of |
| 95 | + * `xs` to themselves. Also, it is required that `ys` is at least |
| 96 | + * as long as `xs`. |
| 97 | + */ |
| 98 | + def (xs: List[T]) zipWithConserve [T, U] (ys: List[U])(f: (T, U) => T): List[T] = |
| 99 | + if (xs.isEmpty || ys.isEmpty) Nil |
| 100 | + else { |
| 101 | + val x1 = f(xs.head, ys.head) |
| 102 | + val xs1 = xs.tail.zipWithConserve(ys.tail)(f) |
| 103 | + if ((x1.asInstanceOf[AnyRef] eq xs.head.asInstanceOf[AnyRef]) && |
| 104 | + (xs1 eq xs.tail)) xs |
| 105 | + else x1 :: xs1 |
| 106 | + } |
| 107 | + |
| 108 | + def (xs: List[T]) hasSameLengthAs [T, U] (ys: List[U]): Boolean = { |
| 109 | + @tailrec def loop(xs: List[T], ys: List[U]): Boolean = |
| 110 | + if (xs.isEmpty) ys.isEmpty |
| 111 | + else ys.nonEmpty && loop(xs.tail, ys.tail) |
| 112 | + loop(xs, ys) |
| 113 | + } |
| 114 | + |
| 115 | + @tailrec |
| 116 | + def (xs: List[T]) eqElements [T] (ys: List[AnyRef]): Boolean = xs match { |
| 117 | + case x :: _ => |
| 118 | + ys match { |
| 119 | + case y :: _ => |
| 120 | + x.asInstanceOf[AnyRef].eq(y) && |
| 121 | + xs.tail.eqElements(ys.tail) |
| 122 | + case _ => false |
| 123 | + } |
| 124 | + case nil => ys.isEmpty |
| 125 | + } |
| 126 | + |
| 127 | + def (xs: List[T]) | [T] (ys: List[T]): List[T] = xs ::: (ys filterNot (xs contains _)) |
| 128 | + |
| 129 | + /** Intersection on lists seen as sets */ |
| 130 | + def (xs: List[T]) & [T] (ys: List[T]): List[T] = xs filter (ys contains _) |
| 131 | + |
| 132 | + def (xss: List[List[T]]) nestedMap [T, U] (f: T => U): List[List[U]] = xss map (_ map f) |
| 133 | + def (xss: List[List[T]]) nestedMapconserve [T, U](f: T => U): List[List[U]] = xss mapconserve (_ mapconserve f) |
| 134 | + |
| 135 | + def (text: Text) show given (ctx: Context): String = |
| 136 | + text.mkString(ctx.settings.pageWidth.value, ctx.settings.printLines.value) |
| 137 | + |
| 138 | + /** Test whether a list of strings representing phases contains |
| 139 | + * a given phase. See [[config.CompilerCommand#explainAdvanced]] for the |
| 140 | + * exact meaning of "contains" here. |
| 141 | + */ |
| 142 | + def (names: List[String]) containsPhase (phase: Phase): Boolean = |
| 143 | + names.nonEmpty && { |
| 144 | + phase match { |
| 145 | + case phase: MegaPhase => phase.miniPhases.exists(names.containsPhase(_)) |
| 146 | + case _ => |
| 147 | + names exists { name => |
| 148 | + name == "all" || { |
| 149 | + val strippedName = name.stripSuffix("+") |
| 150 | + val logNextPhase = name != strippedName |
| 151 | + phase.phaseName.startsWith(strippedName) || |
| 152 | + (logNextPhase && phase.prev.phaseName.startsWith(strippedName)) |
| 153 | + } |
| 154 | + } |
| 155 | + } |
| 156 | + } |
| 157 | + |
| 158 | + def (x: T) reporting [T] (op: T => String, printer: config.Printers.Printer = config.Printers.default): T = { |
| 159 | + printer.println(op(x)) |
| 160 | + x |
| 161 | + } |
| 162 | + |
| 163 | + def (x: T) assertingErrorsReported [T] given Context: T = { |
| 164 | + assert(the[Context].reporter.errorsReported) |
| 165 | + x |
| 166 | + } |
| 167 | + |
| 168 | + def (x: T) assertingErrorsReported [T] (msg: => String) given Context: T = { |
| 169 | + assert(the[Context].reporter.errorsReported, msg) |
| 170 | + x |
| 171 | + } |
| 172 | + |
| 173 | + /** General purpose string formatting */ |
| 174 | + def (sc: StringContext) i (args: Any*) given Context: String = |
| 175 | + new StringFormatter(sc).assemble(args) |
| 176 | + |
| 177 | + /** Formatting for error messages: Like `i` but suppress follow-on |
| 178 | + * error messages after the first one if some of their arguments are "non-sensical". |
| 179 | + */ |
| 180 | + def (sc: StringContext) em (args: Any*) given Context: String = |
| 181 | + new ErrorMessageFormatter(sc).assemble(args) |
| 182 | + |
| 183 | + /** Formatting with added explanations: Like `em`, but add explanations to |
| 184 | + * give more info about type variables and to disambiguate where needed. |
| 185 | + */ |
| 186 | + def (sc: StringContext) ex (args: Any*) given Context: String = |
| 187 | + explained(sc.em(args: _*)) |
| 188 | + |
| 189 | + /** Formatter that adds syntax highlighting to all interpolated values */ |
| 190 | + def (sc: StringContext) hl (args: Any*) given Context: String = |
| 191 | + new SyntaxFormatter(sc).assemble(args).stripMargin |
| 192 | + |
| 193 | + def (arr: Array[T]) binarySearch [T <: AnyRef] (x: T): Int = |
| 194 | + java.util.Arrays.binarySearch(arr.asInstanceOf[Array[Object]], x) |
| 195 | + } |
| 196 | + |
| 197 | + /** Entrypoint for explanation string interpolator: |
| 198 | + * |
| 199 | + * ``` |
| 200 | + * ex"disambiguate $tpe1 and $tpe2" |
| 201 | + * ``` |
| 202 | + */ |
| 203 | + def explained(op: given Context => String) given Context: String = |
| 204 | + printing.Formatting.explained(ctx => op given ctx) |
| 205 | +} |
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