From ab7857b7b2c122012bedb6e173753d41c1063efa Mon Sep 17 00:00:00 2001 From: Vlad Ureche Date: Tue, 2 Oct 2012 11:49:05 +0200 Subject: Improved the `scala.language` documentation Also corrected the links in the library rootdoc. **Note: We need to fast track this commit so it reaches master in the next 12 hours, before we generate the next nightly docs.** Review by @odersky --- .../scala/tools/nsc/doc/html/HtmlPage.scala | 2 +- .../nsc/doc/model/comment/CommentFactory.scala | 2 +- src/library/rootdoc.txt | 21 +++--- src/library/scala/language.scala | 79 ++++++++++++++++++---- 4 files changed, 77 insertions(+), 27 deletions(-) (limited to 'src') diff --git a/src/compiler/scala/tools/nsc/doc/html/HtmlPage.scala b/src/compiler/scala/tools/nsc/doc/html/HtmlPage.scala index 2c719e5d70..b47e9f5784 100644 --- a/src/compiler/scala/tools/nsc/doc/html/HtmlPage.scala +++ b/src/compiler/scala/tools/nsc/doc/html/HtmlPage.scala @@ -117,7 +117,7 @@ abstract class HtmlPage extends Page { thisPage => case Underline(in) => { inlineToHtml(in) } case Superscript(in) => { inlineToHtml(in) } case Subscript(in) => { inlineToHtml(in) } - case Link(raw, title) => { inlineToHtml(title) } + case Link(raw, title) => { inlineToHtml(title) } case Monospace(in) => { inlineToHtml(in) } case Text(text) => scala.xml.Text(text) case Summary(in) => inlineToHtml(in) diff --git a/src/compiler/scala/tools/nsc/doc/model/comment/CommentFactory.scala b/src/compiler/scala/tools/nsc/doc/model/comment/CommentFactory.scala index 1baa7f9831..924ebb8a3b 100644 --- a/src/compiler/scala/tools/nsc/doc/model/comment/CommentFactory.scala +++ b/src/compiler/scala/tools/nsc/doc/model/comment/CommentFactory.scala @@ -147,7 +147,7 @@ trait CommentFactory { thisFactory: ModelFactory with CommentFactory with Member case (group, body) => try { body match { - case Body(List(Paragraph(Chain(List(Summary(Text(prio))))))) => List(group -> prio.toInt) + case Body(List(Paragraph(Chain(List(Summary(Text(prio))))))) => List(group -> prio.trim.toInt) case _ => List() } } catch { diff --git a/src/library/rootdoc.txt b/src/library/rootdoc.txt index da27a0084b..0722d808bf 100644 --- a/src/library/rootdoc.txt +++ b/src/library/rootdoc.txt @@ -4,24 +4,25 @@ This is the documentation for the Scala standard library. The [[scala]] package contains core types. -scala.[[scala.collection]] and its subpackages contain a collections framework with higher-order functions for manipulation. Both [[scala.collection.immutable]] and [[scala.collection.mutable]] data structures are available, with immutable as the default. The [[scala.collection.parallel]] collections provide automatic parallel operation. +[[scala.collection `scala.collection`]] and its subpackages contain a collections framework with higher-order functions for manipulation. Both [[scala.collection.immutable `scala.collection.immutable`]] and [[scala.collection.mutable `scala.collection.mutable`]] data structures are available, with immutable as the default. The [[scala.collection.parallel `scala.collection.parallel`]] collections provide automatic parallel operation. Other important packages include: - - scala.[[scala.actors]] - Concurrency framework inspired by Erlang. - - scala.[[scala.io]] - Input and output. - - scala.[[scala.math]] - Basic math functions and additional numeric types. - - scala.[[scala.sys]] - Interaction with other processes and the operating system. - - scala.util.[[scala.util.matching]] - Pattern matching in text using regular expressions. - - scala.util.parsing.[[scala.util.parsing.combinator]] - Composable combinators for parsing. - - scala.[[scala.xml]] - XML parsing, manipulation, and serialization. + - [[scala.actors `scala.actors`]] - Concurrency framework inspired by Erlang. + - [[scala.io `scala.io`]] - Input and output. + - [[scala.math `scala.math`]] - Basic math functions and additional numeric types. + - [[scala.sys `scala.sys`]] - Interaction with other processes and the operating system. + - [[scala.util.matching `scala.util.matching`]] - Pattern matching in text using regular expressions. + - [[scala.util.parsing.combinator `scala.util.parsing.combinator`]] - Composable combinators for parsing. + - [[scala.xml `scala.xml`]] - XML parsing, manipulation, and serialization. Many other packages exist. See the complete list on the left. == Automatic imports == -Identifiers in the scala package and the [[scala.Predef]] object are always in scope by default. +Identifiers in the scala package and the [[scala.Predef `scala.Predef`]] object are always in scope by default. -Some of these identifiers are type aliases provided as shortcuts to commonly used classes. For example, `List` is an alias for scala.collection.immutable.[[scala.collection.immutable.List]]. +Some of these identifiers are type aliases provided as shortcuts to commonly used classes. For example, `List` is an alias for +[[scala.collection.immutable.List `scala.collection.immutable.List`]]. Other aliases refer to classes provided by the underlying platform. For example, on the JVM, `String` is an alias for `java.lang.String`. diff --git a/src/library/scala/language.scala b/src/library/scala/language.scala index 297f344f65..c638f531bb 100644 --- a/src/library/scala/language.scala +++ b/src/library/scala/language.scala @@ -1,5 +1,28 @@ package scala +/** + * The `scala.language` object controls the language features available to the programmer, as proposed in the + * [[https://docs.google.com/document/d/1nlkvpoIRkx7at1qJEZafJwthZ3GeIklTFhqmXMvTX9Q/edit '''SIP-18 document''']]. + * + * Each of these features has to be explicitly imported into the current scope to become available: + * {{{ + * import language.postfixOps // or language._ + * List(1, 2, 3) reverse + * }}} + * + * The language features are: + * - [[dynamics `dynamics`]] enables defining calls rewriting using the [[scala.Dynamic `Dynamic`]] trait + * - [[postfixOps `postfixOps`]] enables postfix operators + * - [[reflectiveCalls `reflectiveCalls`]] enables using structural types + * - [[implicitConversions `implicitConversions`]] enables defining implicit methods and members + * - [[higherKinds `higherKinds`]] enables writing higher-kinded types + * - [[existentials `existentials`]] enables writing existential types + * - [[experimental `experimental`]] contains newer features that have not yet been tested in production + * + * @groupname production Language Features + * @groupname experimental Experimental Language Features + * @groupprio experimental 10 + */ object language { import languageFeature._ @@ -10,21 +33,25 @@ object language { * selection of existing subclasses of trait Dynamic are unaffected; * they can be used anywhere. * - * _Why introduce the feature?_ To enable flexible DSLs and convenient interfacing + * '''Why introduce the feature?''' To enable flexible DSLs and convenient interfacing * with dynamic languages. * - * _Why control it?_ Dynamic member selection can undermine static checkability + * '''Why control it?''' Dynamic member selection can undermine static checkability * of programs. Furthermore, dynamic member selection often relies on reflection, * which is not available on all platforms. + * + * @group production */ implicit lazy val dynamics: dynamics = languageFeature.dynamics /** Only where enabled, postfix operator notation `(expr op)` will be allowed. * - * _Why keep the feature?_ Several DSLs written in Scala need the notation. + * '''Why keep the feature?''' Several DSLs written in Scala need the notation. * - * _Why control it?_ Postfix operators interact poorly with semicolon inference. + * '''Why control it?''' Postfix operators interact poorly with semicolon inference. * Most programmers avoid them for this reason. + * + * @group production */ implicit lazy val postfixOps: postfixOps = languageFeature.postfixOps @@ -34,13 +61,15 @@ object language { * not override any member in `Parents`. To access one of these members, a * reflective call is needed. * - * _Why keep the feature?_ Structural types provide great flexibility because + * '''Why keep the feature?''' Structural types provide great flexibility because * they avoid the need to define inheritance hierarchies a priori. Besides, * their definition falls out quite naturally from Scala’s concept of type refinement. * - * _Why control it?+ Reflection is not available on all platforms. Popular tools + * '''Why control it?''' Reflection is not available on all platforms. Popular tools * such as ProGuard have problems dealing with it. Even where reflection is available, * reflective dispatch can lead to surprising performance degradations. + * + * @group production */ implicit lazy val reflectiveCalls: reflectiveCalls = languageFeature.reflectiveCalls @@ -49,32 +78,36 @@ object language { * or an implicit method that has in its first parameter section a single, * non-implicit parameter. Examples: * + * {{{ * implicit def stringToInt(s: String): Int = s.length * implicit val conv = (s: String) => s.length - * implicit def listToX(xs: List[T])(implicit f: T => X): X = … + * implicit def listToX(xs: List[T])(implicit f: T => X): X = ... + * }}} * * implicit values of other types are not affected, and neither are implicit * classes. * - * _Why keep the feature?_ Implicit conversions are central to many aspects + * '''Why keep the feature?''' Implicit conversions are central to many aspects * of Scala’s core libraries. * - * _Why control it?_ Implicit conversions are known to cause many pitfalls + * '''Why control it?''' Implicit conversions are known to cause many pitfalls * if over-used. And there is a tendency to over-use them because they look * very powerful and their effects seem to be easy to understand. Also, in * most situations using implicit parameters leads to a better design than * implicit conversions. + * + * @group production */ implicit lazy val implicitConversions: implicitConversions = languageFeature.implicitConversions /** Only where this flag is enabled, higher-kinded types can be written. * - * _Why keep the feature?_ Higher-kinded types enable the definition of very general + * '''Why keep the feature?''' Higher-kinded types enable the definition of very general * abstractions such as functor, monad, or arrow. A significant set of advanced * libraries relies on them. Higher-kinded types are also at the core of the * scala-virtualized effort to produce high-performance parallel DSLs through staging. * - * _Why control it?_ Higher kinded types in Scala lead to a Turing-complete + * '''Why control it?''' Higher kinded types in Scala lead to a Turing-complete * type system, where compiler termination is no longer guaranteed. They tend * to be useful mostly for type-level computation and for highly generic design * patterns. The level of abstraction implied by these design patterns is often @@ -85,6 +118,8 @@ object language { * higher-kinded types will change in future versions of Scala. So an explicit * enabling also serves as a warning that code involving higher-kinded types * might have to be slightly revised in the future. + * + * @group production */ implicit lazy val higherKinds: higherKinds = languageFeature.higherKinds @@ -93,17 +128,31 @@ object language { * types of methods. Existential types with wildcard type syntax such as `List[_]`, * or `Map[String, _]` are not affected. * - * _Why keep the feature?_ Existential types are needed to make sense of Java’s wildcard + * '''Why keep the feature?''' Existential types are needed to make sense of Java’s wildcard * types and raw types and the erased types of run-time values. * - * Why control it? Having complex existential types in a code base usually makes + * '''Why control it?''' Having complex existential types in a code base usually makes * application code very brittle, with a tendency to produce type errors with * obscure error messages. Therefore, going overboard with existential types * is generally perceived not to be a good idea. Also, complicated existential types * might be no longer supported in a future simplification of the language. + * + * @group production */ implicit lazy val existentials: existentials = languageFeature.existentials + /** The experimental object contains features that have been recently added but have not + * been thoroughly tested in production yet. + * + * Experimental features '''may undergo API changes''' in future releases, so production + * code should not rely on them. + * + * Programmers are encouraged to try out experimental features and + * [[http://issues.scala-lang.org report any bugs or API inconsistencies]] + * they encounter so they can be improved in future releases. + * + * @group experimental + */ object experimental { import languageFeature.experimental._ @@ -111,12 +160,12 @@ object language { /** Where enabled, macro definitions are allowed. Macro implementations and * macro applications are unaffected; they can be used anywhere. * - * _Why introduce the feature?_ Macros promise to make the language more regular, + * '''Why introduce the feature?''' Macros promise to make the language more regular, * replacing ad-hoc language constructs with a general powerful abstraction * capability that can express them. Macros are also a more disciplined and * powerful replacement for compiler plugins. * - * _Why control it?_ For their very power, macros can lead to code that is hard + * '''Why control it?''' For their very power, macros can lead to code that is hard * to debug and understand. */ implicit lazy val macros: macros = languageFeature.experimental.macros -- cgit v1.2.3