Scala example source code file (AnyVals.scala)
The AnyVals.scala Scala example source code
/* NSC -- new Scala compiler
* Copyright 2007-2013 LAMP/EPFL
* @author Paul Phillips
*/
package scala.tools.cmd
package gen
/** Code generation of the AnyVal types and their companions. */
trait AnyValReps {
self: AnyVals =>
sealed abstract class AnyValNum(name: String, repr: Option[String], javaEquiv: String)
extends AnyValRep(name,repr,javaEquiv) {
case class Op(op : String, doc : String)
private def companionCoercions(tos: AnyValRep*) = {
tos.toList map (to =>
s"implicit def @javaequiv@2${to.javaEquiv}(x: @name@): ${to.name} = x.to${to.name}"
)
}
def coercionComment =
"""/** Language mandated coercions from @name@ to "wider" types. */
import scala.language.implicitConversions"""
def implicitCoercions: List[String] = {
val coercions = this match {
case B => companionCoercions(S, I, L, F, D)
case S | C => companionCoercions(I, L, F, D)
case I => companionCoercions(L, F, D)
case L => companionCoercions(F, D)
case F => companionCoercions(D)
case _ => Nil
}
if (coercions.isEmpty) Nil
else coercionComment.lines.toList ++ coercions
}
def isCardinal: Boolean = isIntegerType(this)
def unaryOps = {
val ops = List(
Op("+", "/** Returns this value, unmodified. */"),
Op("-", "/** Returns the negation of this value. */"))
if(isCardinal)
Op("~", "/**\n" +
" * Returns the bitwise negation of this value.\n" +
" * @example {{{\n" +
" * ~5 == -6\n" +
" * // in binary: ~00000101 ==\n" +
" * // 11111010\n" +
" * }}}\n" +
" */") :: ops
else ops
}
def bitwiseOps =
if (isCardinal)
List(
Op("|", "/**\n" +
" * Returns the bitwise OR of this value and `x`.\n" +
" * @example {{{\n" +
" * (0xf0 | 0xaa) == 0xfa\n" +
" * // in binary: 11110000\n" +
" * // | 10101010\n" +
" * // --------\n" +
" * // 11111010\n" +
" * }}}\n" +
" */"),
Op("&", "/**\n" +
" * Returns the bitwise AND of this value and `x`.\n" +
" * @example {{{\n" +
" * (0xf0 & 0xaa) == 0xa0\n" +
" * // in binary: 11110000\n" +
" * // & 10101010\n" +
" * // --------\n" +
" * // 10100000\n" +
" * }}}\n" +
" */"),
Op("^", "/**\n" +
" * Returns the bitwise XOR of this value and `x`.\n" +
" * @example {{{\n" +
" * (0xf0 ^ 0xaa) == 0x5a\n" +
" * // in binary: 11110000\n" +
" * // ^ 10101010\n" +
" * // --------\n" +
" * // 01011010\n" +
" * }}}\n" +
" */"))
else Nil
def shiftOps =
if (isCardinal)
List(
Op("<<", "/**\n" +
" * Returns this value bit-shifted left by the specified number of bits,\n" +
" * filling in the new right bits with zeroes.\n" +
" * @example {{{ 6 << 3 == 48 // in binary: 0110 << 3 == 0110000 }}}\n" +
" */"),
Op(">>>", "/**\n" +
" * Returns this value bit-shifted right by the specified number of bits,\n" +
" * filling the new left bits with zeroes.\n" +
" * @example {{{ 21 >>> 3 == 2 // in binary: 010101 >>> 3 == 010 }}}\n" +
" * @example {{{\n" +
" * -21 >>> 3 == 536870909\n" +
" * // in binary: 11111111 11111111 11111111 11101011 >>> 3 ==\n" +
" * // 00011111 11111111 11111111 11111101\n" +
" * }}}\n" +
" */"),
Op(">>", "/**\n" +
" * Returns this value bit-shifted left by the specified number of bits,\n" +
" * filling in the right bits with the same value as the left-most bit of this.\n" +
" * The effect of this is to retain the sign of the value.\n" +
" * @example {{{\n" +
" * -21 >> 3 == -3\n" +
" * // in binary: 11111111 11111111 11111111 11101011 >> 3 ==\n" +
" * // 11111111 11111111 11111111 11111101\n" +
" * }}}\n" +
" */"))
else Nil
def comparisonOps = List(
Op("==", "/** Returns `true` if this value is equal to x, `false` otherwise. */"),
Op("!=", "/** Returns `true` if this value is not equal to x, `false` otherwise. */"),
Op("<", "/** Returns `true` if this value is less than x, `false` otherwise. */"),
Op("<=", "/** Returns `true` if this value is less than or equal to x, `false` otherwise. */"),
Op(">", "/** Returns `true` if this value is greater than x, `false` otherwise. */"),
Op(">=", "/** Returns `true` if this value is greater than or equal to x, `false` otherwise. */"))
def otherOps = List(
Op("+", "/** Returns the sum of this value and `x`. */"),
Op("-", "/** Returns the difference of this value and `x`. */"),
Op("*", "/** Returns the product of this value and `x`. */"),
Op("/", "/** Returns the quotient of this value and `x`. */"),
Op("%", "/** Returns the remainder of the division of this value by `x`. */"))
// Given two numeric value types S and T , the operation type of S and T is defined as follows:
// If both S and T are subrange types then the operation type of S and T is Int.
// Otherwise the operation type of S and T is the larger of the two types wrt ranking.
// Given two numeric values v and w the operation type of v and w is the operation type
// of their run-time types.
def opType(that: AnyValNum): AnyValNum = {
val rank = IndexedSeq(I, L, F, D)
(rank indexOf this, rank indexOf that) match {
case (-1, -1) => I
case (r1, r2) => rank apply (r1 max r2)
}
}
def mkCoercions = numeric map (x => "def to%s: %s".format(x, x))
def mkUnaryOps = unaryOps map (x => "%s\n def unary_%s : %s".format(x.doc, x.op, this opType I))
def mkStringOps = List("def +(x: String): String")
def mkShiftOps = (
for (op <- shiftOps ; arg <- List(I, L)) yield
"%s\n def %s(x: %s): %s".format(op.doc, op.op, arg, this opType I)
)
def clumps: List[List[String]] = {
val xs1 = List(mkCoercions, mkUnaryOps, mkStringOps, mkShiftOps) map (xs => if (xs.isEmpty) xs else xs :+ "")
val xs2 = List(
mkBinOpsGroup(comparisonOps, numeric, _ => Z),
mkBinOpsGroup(bitwiseOps, cardinal, this opType _),
mkBinOpsGroup(otherOps, numeric, this opType _)
)
xs1 ++ xs2
}
def classLines = (clumps :+ commonClassLines).foldLeft(List[String]()) {
case (res, Nil) => res
case (res, lines) =>
val xs = lines map {
case "" => ""
case s => interpolate(s)
}
res ++ xs
}
def objectLines = {
val comp = if (isCardinal) cardinalCompanion else floatingCompanion
interpolate(comp + allCompanions + "\n" + nonUnitCompanions).trim.lines.toList ++ (implicitCoercions map interpolate)
}
/** Makes a set of binary operations based on the given set of ops, args, and resultFn.
*
* @param ops list of function names e.g. List(">>", "%")
* @param args list of types which should appear as arguments
* @param resultFn function which calculates return type based on arg type
* @return list of function definitions
*/
def mkBinOpsGroup(ops: List[Op], args: List[AnyValNum], resultFn: AnyValNum => AnyValRep): List[String] = (
ops flatMap (op =>
args.map(arg =>
"%s\n def %s(x: %s): %s".format(op.doc, op.op, arg, resultFn(arg))) :+ ""
)
).toList
}
sealed abstract class AnyValRep(val name: String, val repr: Option[String], val javaEquiv: String) {
def classLines: List[String]
def objectLines: List[String]
def commonClassLines = List(
"override def getClass(): Class[@name@] = null"
)
def lcname = name.toLowerCase
def boxedSimpleName = this match {
case C => "Character"
case I => "Integer"
case _ => name
}
def boxedName = this match {
case U => "scala.runtime.BoxedUnit"
case _ => "java.lang." + boxedSimpleName
}
def zeroRep = this match {
case L => "0L"
case F => "0.0f"
case D => "0.0d"
case _ => "0"
}
def representation = repr.map(", a " + _).getOrElse("")
def indent(s: String) = if (s == "") "" else " " + s
def indentN(s: String) = s.lines map indent mkString "\n"
def boxUnboxImpls = Map(
"@boxRunTimeDoc@" -> """
* Runtime implementation determined by `scala.runtime.BoxesRunTime.boxTo%s`. See [[https://github.com/scala/scala src/library/scala/runtime/BoxesRunTime.java]].
*""".format(boxedSimpleName),
"@boxImpl@" -> "%s.valueOf(x)".format(boxedName),
"@unboxRunTimeDoc@" -> """
* Runtime implementation determined by `scala.runtime.BoxesRunTime.unboxTo%s`. See [[https://github.com/scala/scala src/library/scala/runtime/BoxesRunTime.java]].
*""".format(name),
"@unboxImpl@" -> "x.asInstanceOf[%s].%sValue()".format(boxedName, lcname),
"@unboxDoc@" -> "the %s resulting from calling %sValue() on `x`".format(name, lcname)
)
def interpolations = Map(
"@name@" -> name,
"@representation@" -> representation,
"@javaequiv@" -> javaEquiv,
"@boxed@" -> boxedName,
"@lcname@" -> lcname,
"@zero@" -> zeroRep
) ++ boxUnboxImpls
def interpolate(s: String): String = interpolations.foldLeft(s) {
case (str, (key, value)) => str.replaceAll(key, value)
}
def classDoc = interpolate(classDocTemplate)
def objectDoc = ""
def mkImports = ""
def mkClass = assemble("final abstract class " + name + " private extends AnyVal", classLines)
def mkObject = assemble("object " + name + " extends AnyValCompanion", objectLines)
def make() = List[String](
headerTemplate,
mkImports,
classDoc,
mkClass,
objectDoc,
mkObject
) mkString ""
def assemble(decl: String, lines: List[String]): String = {
val body = if (lines.isEmpty) " { }\n\n" else lines map indent mkString (" {\n", "\n", "\n}\n")
decl + body + "\n"
}
override def toString = name
}
}
trait AnyValTemplates {
def headerTemplate = """/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2002-2013, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
// DO NOT EDIT, CHANGES WILL BE LOST
// This auto-generated code can be modified in scala.tools.cmd.gen.
// Afterwards, running tools/codegen-anyvals regenerates this source file.
package scala
"""
def classDocTemplate = ("""
/** `@name@`@representation@ (equivalent to Java's `@javaequiv@` primitive type) is a
* subtype of [[scala.AnyVal]]. Instances of `@name@` are not
* represented by an object in the underlying runtime system.
*
* There is an implicit conversion from [[scala.@name@]] => [[scala.runtime.Rich@name@]]
* which provides useful non-primitive operations.
*/
""".trim + "\n")
def allCompanions = """
/** Transform a value type into a boxed reference type.
*@boxRunTimeDoc@
* @param x the @name@ to be boxed
* @return a @boxed@ offering `x` as its underlying value.
*/
def box(x: @name@): @boxed@ = @boxImpl@
/** Transform a boxed type into a value type. Note that this
* method is not typesafe: it accepts any Object, but will throw
* an exception if the argument is not a @boxed@.
*@unboxRunTimeDoc@
* @param x the @boxed@ to be unboxed.
* @throws ClassCastException if the argument is not a @boxed@
* @return @unboxDoc@
*/
def unbox(x: java.lang.Object): @name@ = @unboxImpl@
/** The String representation of the scala.@name@ companion object. */
override def toString = "object scala.@name@"
"""
def nonUnitCompanions = "" // todo
def cardinalCompanion = """
/** The smallest value representable as a @name@. */
final val MinValue = @boxed@.MIN_VALUE
/** The largest value representable as a @name@. */
final val MaxValue = @boxed@.MAX_VALUE
"""
def floatingCompanion = """
/** The smallest positive value greater than @zero@ which is
* representable as a @name@.
*/
final val MinPositiveValue = @boxed@.MIN_VALUE
final val NaN = @boxed@.NaN
final val PositiveInfinity = @boxed@.POSITIVE_INFINITY
final val NegativeInfinity = @boxed@.NEGATIVE_INFINITY
/** The negative number with the greatest (finite) absolute value which is representable
* by a @name@. Note that it differs from [[java.lang.@name@.MIN_VALUE]], which
* is the smallest positive value representable by a @name@. In Scala that number
* is called @name@.MinPositiveValue.
*/
final val MinValue = -@boxed@.MAX_VALUE
/** The largest finite positive number representable as a @name@. */
final val MaxValue = @boxed@.MAX_VALUE
"""
}
class AnyVals extends AnyValReps with AnyValTemplates {
object B extends AnyValNum("Byte", Some("8-bit signed integer"), "byte")
object S extends AnyValNum("Short", Some("16-bit signed integer"), "short")
object C extends AnyValNum("Char", Some("16-bit unsigned integer"), "char")
object I extends AnyValNum("Int", Some("32-bit signed integer"), "int")
object L extends AnyValNum("Long", Some("64-bit signed integer"), "long")
object F extends AnyValNum("Float", Some("32-bit IEEE-754 floating point number"), "float")
object D extends AnyValNum("Double", Some("64-bit IEEE-754 floating point number"), "double")
object Z extends AnyValRep("Boolean", None, "boolean") {
def classLines = """
/** Negates a Boolean expression.
*
* - `!a` results in `false` if and only if `a` evaluates to `true` and
* - `!a` results in `true` if and only if `a` evaluates to `false`.
*
* @return the negated expression
*/
def unary_! : Boolean
/** Compares two Boolean expressions and returns `true` if they evaluate to the same value.
*
* `a == b` returns `true` if and only if
* - `a` and `b` are `true` or
* - `a` and `b` are `false`.
*/
def ==(x: Boolean): Boolean
/**
* Compares two Boolean expressions and returns `true` if they evaluate to a different value.
*
* `a != b` returns `true` if and only if
* - `a` is `true` and `b` is `false` or
* - `a` is `false` and `b` is `true`.
*/
def !=(x: Boolean): Boolean
/** Compares two Boolean expressions and returns `true` if one or both of them evaluate to true.
*
* `a || b` returns `true` if and only if
* - `a` is `true` or
* - `b` is `true` or
* - `a` and `b` are `true`.
*
* @note This method uses 'short-circuit' evaluation and
* behaves as if it was declared as `def ||(x: => Boolean): Boolean`.
* If `a` evaluates to `true`, `true` is returned without evaluating `b`.
*/
def ||(x: Boolean): Boolean
/** Compares two Boolean expressions and returns `true` if both of them evaluate to true.
*
* `a && b` returns `true` if and only if
* - `a` and `b` are `true`.
*
* @note This method uses 'short-circuit' evaluation and
* behaves as if it was declared as `def &&(x: => Boolean): Boolean`.
* If `a` evaluates to `false`, `false` is returned without evaluating `b`.
*/
def &&(x: Boolean): Boolean
// Compiler won't build with these seemingly more accurate signatures
// def ||(x: => Boolean): Boolean
// def &&(x: => Boolean): Boolean
/** Compares two Boolean expressions and returns `true` if one or both of them evaluate to true.
*
* `a | b` returns `true` if and only if
* - `a` is `true` or
* - `b` is `true` or
* - `a` and `b` are `true`.
*
* @note This method evaluates both `a` and `b`, even if the result is already determined after evaluating `a`.
*/
def |(x: Boolean): Boolean
/** Compares two Boolean expressions and returns `true` if both of them evaluate to true.
*
* `a & b` returns `true` if and only if
* - `a` and `b` are `true`.
*
* @note This method evaluates both `a` and `b`, even if the result is already determined after evaluating `a`.
*/
def &(x: Boolean): Boolean
/** Compares two Boolean expressions and returns `true` if they evaluate to a different value.
*
* `a ^ b` returns `true` if and only if
* - `a` is `true` and `b` is `false` or
* - `a` is `false` and `b` is `true`.
*/
def ^(x: Boolean): Boolean
override def getClass(): Class[Boolean] = null
""".trim.lines.toList
def objectLines = interpolate(allCompanions + "\n" + nonUnitCompanions).lines.toList
}
object U extends AnyValRep("Unit", None, "void") {
override def classDoc = """
/** `Unit` is a subtype of [[scala.AnyVal]]. There is only one value of type
* `Unit`, `()`, and it is not represented by any object in the underlying
* runtime system. A method with return type `Unit` is analogous to a Java
* method which is declared `void`.
*/
"""
def classLines = List(
"""override def getClass(): Class[Unit] = null"""
)
def objectLines = interpolate(allCompanions).lines.toList
override def boxUnboxImpls = Map(
"@boxRunTimeDoc@" -> "",
"@boxImpl@" -> "scala.runtime.BoxedUnit.UNIT",
"@unboxRunTimeDoc@" -> "",
"@unboxImpl@" -> "()",
"@unboxDoc@" -> "the Unit value ()"
)
}
def isSubrangeType = Set(B, S, C)
def isIntegerType = Set(B, S, C, I, L)
def isFloatingType = Set(F, D)
def isWideType = Set(L, D)
def cardinal = numeric filter isIntegerType
def numeric = List(B, S, C, I, L, F, D)
def values = List(U, Z) ++ numeric
def make() = values map (x => (x.name, x.make()))
}
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