class IMain extends Repl with Imports with PresentationCompilation with Closeable

An interpreter for Scala code.

The main public entry points are compile(), interpret(), and bind(). The compile() method loads a complete Scala file. The interpret() method executes one line of Scala code at the request of the user. The bind() method binds an object to a variable that can then be used by later interpreted code.

The overall approach is based on compiling the requested code and then using a Java classloader and Java reflection to run the code and access its results.

In more detail, a single compiler instance is used to accumulate all successfully compiled or interpreted Scala code. To "interpret" a line of code, the compiler generates a fresh object that includes the line of code and which has public member(s) to export all variables defined by that code. To extract the result of an interpreted line to show the user, a second "result object" is created which imports the variables exported by the above object and then exports members called "$eval" and "$print". To accommodate user expressions that read from variables or methods defined in previous statements, "import" statements are used.

This interpreter shares the strengths and weaknesses of using the full compiler-to-Java. The main strength is that interpreted code behaves exactly as does compiled code, including running at full speed. The main weakness is that redefining classes and methods is not handled properly, because rebinding at the Java level is technically difficult.

Source
IMain.scala
Linear Supertypes
Closeable, AutoCloseable, PresentationCompilation, Imports, Repl, ReplCore, AnyRef, Any
Known Subclasses
ScriptedInterpreter
Type Hierarchy
Ordering
  1. Alphabetic
  2. By Inheritance
Inherited
  1. IMain
  2. Closeable
  3. AutoCloseable
  4. PresentationCompilation
  5. Imports
  6. Repl
  7. ReplCore
  8. AnyRef
  9. Any
Implicitly
  1. by any2stringadd
  2. by StringFormat
  3. by Ensuring
  4. by ArrowAssoc
  1. Hide All
  2. Show All
Visibility
  1. Public
  2. Protected

Instance Constructors

  1. new IMain(interpreterSettings: Settings, reporter: ReplReporter)
  2. new IMain(settings: Settings, parentClassLoaderOverride: Option[ClassLoader], compilerSettings: Settings, reporter: ReplReporter)

Type Members

  1. abstract class PhaseDependentOps extends AnyRef
  2. class ReadEvalPrint extends AnyRef

    Here is where we:

    Here is where we:

    1) Read some source code, and put it in the "read" object. 2) Evaluate the read object, and put the result in the "eval" object. 3) Create a String for human consumption, and put it in the "print" object.

    Read! Eval! Print! Some of that not yet centralized here.

  3. implicit class ReplTypeOps extends AnyRef
  4. class Request extends ReplRequest

    One line of code submitted by the user for interpretation

  5. type Setting = Settings.Setting
    Definition Classes
    Repl
  6. case class ComputedImports(header: String, prepend: String, append: String, access: String) extends Product with Serializable

    Compute imports that allow definitions from previous requests to be visible in a new request.

    Compute imports that allow definitions from previous requests to be visible in a new request. Returns three or four pieces of related code:

    0. Header code fragment that should go at the beginning of the compilation unit, specifically, import Predef.

    1. An initial code fragment that should go before the code of the new request.

    2. A code fragment that should go after the code of the new request.

    3. An access path which can be traversed to access any bindings inside code wrapped by #1 and #2 .

    The argument is a set of Names that need to be imported.

    Limitations: This method is not as precise as it could be. (1) It does not process wildcard imports to see what exactly they import. (2) If it imports any names from a request, it imports all of them, which is not really necessary. (3) It imports multiple same-named implicits, but only the last one imported is actually usable.

    Definition Classes
    Imports
  7. abstract class PresentationCompileResult extends PresentationCompilationResult
    Definition Classes
    PresentationCompilation

Value Members

  1. def addUrlsToClassPath(urls: URL*): Unit

    Adds all specified jars to the compile and runtime classpaths.

    Adds all specified jars to the compile and runtime classpaths.

    urls

    The list of items to add to the compile and runtime classpaths.

    Definition Classes
    IMain → Repl
    Note

    Currently only supports jars, not directories.

  2. def allDefinedNames: List[Global.Name]
  3. def allHandlers: collection.immutable.List[(memberHandlers)#MemberHandler]
  4. def backticked(s: String): String
  5. final def beQuietDuring(body: => Unit): Unit

    The reporter will not print results during execution of body.

    The reporter will not print results during execution of body.

    Definition Classes
    Repl → ReplCore
  6. def bind[T](name: String, value: T)(implicit arg0: reflect.api.JavaUniverse.TypeTag[T], arg1: ClassTag[T]): Result
  7. def bind(p: NamedParam): Result
    Definition Classes
    IMain → Repl
  8. def bind(name: String, boundType: String, value: Any, modifiers: List[String] = Nil): Result

    Bind a specified name to a specified value.

    Bind a specified name to a specified value. The name may later be used by expressions passed to interpret.

    A fresh ReadEvalPrint, which defines a line package, is used to compile a custom eval object that wraps the bound value.

    If the bound value is successfully installed, then bind the name by interpreting val name = $line42.$eval.value.

    name

    the variable name to bind

    boundType

    the type of the variable, as a string

    value

    the object value to bind to it

    returns

    an indication of whether the binding succeeded

    Definition Classes
    IMain → ReplCore
  9. def bindValue(name: String, value: Any): Result

    Bind a specified name to a specified value.

    Bind a specified name to a specified value. The type is derived from the run-time class of the value.

    Definition Classes
    ReplCore
  10. def classLoader: AbstractFileClassLoader
    Definition Classes
    IMain → Repl
  11. def classOfTerm(id: String): Option[Class[_]]
  12. def classPathString: String
    Definition Classes
    IMain → Repl
  13. def cleanMemberDecl(owner: Global.Symbol, member: Global.Name): Global.Type
  14. def cleanTypeAfterTyper(sym: => Global.Symbol): Global.Type
  15. def clearExecutionWrapper(): Unit
    Definition Classes
    IMain → Repl
  16. def close(): Unit

    This instance is no longer needed, so release any resources it is using.

    This instance is no longer needed, so release any resources it is using. The reporter's output gets flushed.

    Definition Classes
    IMain → Closeable → AutoCloseable → Repl
  17. def compile(line: String, synthetic: Boolean, fatally: Boolean): Either[Result, Request]
  18. def compile(line: String, synthetic: Boolean): Either[Result, Request]
  19. def compileSources(sources: SourceFile*): Boolean

    Compile an nsc SourceFile.

    Compile an nsc SourceFile. Returns true if there are no compilation errors, or false otherwise.

    Definition Classes
    IMain → Repl
  20. def compileSourcesKeepingRun(sources: SourceFile*): (Boolean, Run)
  21. def compileString(code: String): Boolean

    Compile a string.

    Compile a string. Returns true if there are no compilation errors, or false otherwise.

    Definition Classes
    IMain → Repl
  22. def compilerClasspath: Seq[URL]
    Definition Classes
    IMain → Repl
  23. def dealiasNonPublic(tp: Global.Type): Global.Type
  24. def debugging[T](msg: String)(res: T): T
  25. def definedSymbolList: collection.immutable.List[Global.Symbol]
  26. def definedTerms: collection.immutable.List[Global.TermName]
  27. def definedTypes: List[String]
    Definition Classes
    IMain → Repl
  28. def directBind[T](name: String, value: T)(implicit arg0: reflect.api.JavaUniverse.TypeTag[T], arg1: ClassTag[T]): Result
  29. def directBind(p: NamedParam): Result
  30. def directBind(name: String, boundType: String, value: Any): Result
  31. final def ensureClassLoader(): Unit
  32. def executionWrapper: String
  33. def finalize(): Unit
    Definition Classes
    IMain → AnyRef
  34. def flatPath(sym: Global.Symbol): String
  35. def getClassIfDefined(path: String): Global.Symbol
  36. def getModuleIfDefined(path: String): Global.Symbol
  37. lazy val global: Global
  38. def implicitSymbolsBySource: List[(Global.Symbol, List[Global.Symbol])]
    Definition Classes
    Imports
  39. def implicitsCommandInternal(line: String): (List[String], String)
    Definition Classes
    IMain → Repl
  40. def importHandlers: collection.immutable.List[(memberHandlers)#ImportHandler]
  41. def importsCommandInternal(tokens: List[String]): List[String]
    Definition Classes
    IMain → Repl
  42. def initializeCompiler(): Boolean
    Definition Classes
    IMain → Repl
  43. def initializeComplete: Boolean
    Definition Classes
    IMain → Repl
  44. def interpret(line: String, synthetic: Boolean): Result
    Definition Classes
    IMain → Repl
  45. def interpret(line: String): Result

    Interpret one line of input.

    Interpret one line of input. All feedback, including parse errors and evaluation results, are printed via the supplied compiler's reporter. Values defined are available for future interpreted strings.

    The return value is whether the line was interpreted successfully, e.g. that there were no parse errors.

    Definition Classes
    IMain → ReplCore
  46. def interpretFinally(line: String): Result

    Interpret one line of input.

    Interpret one line of input. All feedback, including parse errors and evaluation results, are printed via the supplied compiler's reporter. Values defined are available for future interpreted strings.

    The return value is whether the line was interpreted successfully, e.g. that there were no parse errors.

    Definition Classes
    IMain → Repl
  47. def interpretSynthetic(line: String): Result
  48. lazy val isClassBased: Boolean
  49. def isPackaged(line: String): Boolean

    Does code start with a package definition?

    Does code start with a package definition?

    Definition Classes
    IMain → Repl
  50. def kindCommandInternal(typeString: String, verbose: Boolean): String
    Definition Classes
    IMain → Repl
  51. def languageWildcardHandlers: collection.immutable.List[(memberHandlers)#ImportHandler]
    Definition Classes
    Imports
  52. def lastRequest: Request
  53. def lastWarnings: List[(Global.Position, String)]
    Definition Classes
    IMain → Repl
  54. lazy val memberHandlers: MemberHandlers { val intp: IMain.this.type }
  55. def mostRecentVar: String

    Returns the name of the most recent interpreter result.

    Returns the name of the most recent interpreter result. Mostly this exists so you can conveniently invoke methods on the previous result.

    Definition Classes
    IMain → Repl
  56. def nameToCode(s: String): String
  57. def namedDefinedTerms: List[String]
    Definition Classes
    IMain → Repl
  58. def namedParam[T](name: String, value: T)(implicit arg0: reflect.api.JavaUniverse.TypeTag[T], arg1: ClassTag[T]): NamedParam
    Definition Classes
    IMain → Repl
  59. def newPresentationCompiler(): interactive.Global

    Create an instance of the presentation compiler with a classpath comprising the REPL's configured classpath and the classes output by previously compiled REPL lines.

    Create an instance of the presentation compiler with a classpath comprising the REPL's configured classpath and the classes output by previously compiled REPL lines.

    You may directly interact with this compiler from any thread, although you must not access it concurrently from multiple threads.

    You may downcast the reporter to StoreReporter to access type errors.

    Definition Classes
    PresentationCompilation
  60. def originalPath(sym: Global.Symbol): String
  61. def originalPath(name: Global.Name): String
  62. def originalPath(name: String): String
    Definition Classes
    IMain → Repl
  63. def outputDir: ReplDir
    Definition Classes
    IMain → Repl
  64. def parse(line: String, fatally: Boolean): Either[Result, (List[Global.Tree], Global.Position)]
  65. def parse(line: String): Either[Result, (List[Global.Tree], Global.Position)]

    Parse a line into and return parsing result (error, incomplete or success with list of trees)

  66. def parseString(line: String): Result

    TODO resolve scan, parse, compile, interpret, which just indicate how much work to do.

    TODO resolve scan, parse, compile, interpret, which just indicate how much work to do.

    Definition Classes
    IMain → Repl
  67. lazy val power: Power[StdReplVals]
    Definition Classes
    IMain → Repl
  68. def presentationCompile(cursor: Int, buf: String): Either[Result, PresentationCompilationResult]

    Typecheck a line of REPL input, suitably wrapped with "interpreter wrapper" objects/classes, with the presentation compiler.

    Typecheck a line of REPL input, suitably wrapped with "interpreter wrapper" objects/classes, with the presentation compiler. The result of this method gives access to the typechecked tree and to autocompletion suggestions.

    The caller is responsible for calling PresentationCompileResult#cleanup to dispose of the compiler instance.

    Definition Classes
    PresentationCompilation
  69. def prevRequestList: collection.immutable.List[Request]
  70. def quietBind(p: NamedParam): Result
    Definition Classes
    IMain → Repl
  71. def quietRun(code: String): Result
    Definition Classes
    IMain → Repl
  72. val readInstanceName: String
  73. def readRootPath(readPath: String): Global.Symbol
  74. def rebind(p: NamedParam): Result
  75. def recordRequest(req: Request): Unit
  76. def replScope: Global.Scope
  77. def replStrings: ReplStrings
  78. val reporter: ReplReporter
    Definition Classes
    IMain → Repl
  79. def requestDefining(name: String): Option[Request]
    Definition Classes
    IMain → Repl
  80. def reset(): Unit

    Reset this interpreter, forgetting all user-specified requests.

    Reset this interpreter, forgetting all user-specified requests.

    Definition Classes
    IMain → Repl
  81. def resetClassLoader(): Unit
  82. def runtimeClassAndTypeOfTerm(id: String): Option[(Class[_], Global.Type)]
  83. def runtimeMirror: Mirror
  84. def runtimeTypeOfTerm(id: String): Global.Type
  85. def setExecutionWrapper(code: String): Unit
    Definition Classes
    IMain → Repl
  86. val settings: Settings
    Definition Classes
    IMain → Repl
  87. def showDirectory: String
    Definition Classes
    IMain → Repl
  88. def symbolDefString(sym: Global.Symbol): String
  89. def symbolOfIdent(id: String): Global.Symbol
  90. def symbolOfLine(code: String): Global.Symbol
  91. def symbolOfName(id: Global.Name): Global.Symbol
  92. def symbolOfTerm(id: String): Global.Symbol
  93. def symbolOfType(id: String): Global.Symbol
  94. def tokenize(line: String): List[TokenData]
    Definition Classes
    IMain → Repl
  95. def translateEnclosingClass(n: String): Option[String]
    Definition Classes
    IMain → Repl
  96. def translateOriginalPath(p: String): String
  97. def translatePath(path: String): Option[String]
    Definition Classes
    IMain → Repl
  98. def translateSimpleResource(path: String): Option[String]

    If path represents a class resource in the default package, see if the corresponding symbol has a class file that is a REPL artifact residing at a different resource path.

    If path represents a class resource in the default package, see if the corresponding symbol has a class file that is a REPL artifact residing at a different resource path. Translate X.class to $line3/$read$$iw$$iw$X.class.

  99. def tryTwice(op: => Global.Symbol): Global.Symbol

    It's a bit of a shotgun approach, but for now we will gain in robustness.

    It's a bit of a shotgun approach, but for now we will gain in robustness. Try a symbol-producing operation at phase typer, and if that is NoSymbol, try again at phase flatten. I'll be able to lose this and run only from exitingTyper as soon as I figure out exactly where a flat name is sneaking in when calculating imports.

  100. def typeCommandInternal(expr: String, verbose: Boolean): (String, String)

    TODO - -n normalize -l label with case class parameter names -c complete - leave nothing out

    TODO - -n normalize -l label with case class parameter names -c complete - leave nothing out

    Definition Classes
    IMain → Repl
  101. def typeOfExpression(expr: String, silent: Boolean = true): Global.Type
  102. def typeOfTerm(id: String): Global.Type
  103. def typeToCode(s: String): String
  104. def unqualifiedIds: List[String]
  105. def updateSettings(arguments: List[String]): Boolean
    Definition Classes
    IMain → Repl
  106. def userSetSettings: List[Setting]
    Definition Classes
    IMain → Repl
  107. def valueOfTerm(id: String): Option[Any]
    Definition Classes
    IMain → Repl
  108. def visibleSettings: List[Setting]
    Definition Classes
    IMain → Repl
  109. def withLabel[A](temp: String)(body: => A): A
    Definition Classes
    IMain → Repl
  110. def withSuppressedSettings(body: => Unit): Unit
    Definition Classes
    IMain → Repl
  111. def withoutWarnings[T](body: => T): T
  112. object deconstruct extends StructuredTypeStrings
  113. object exprTyper extends ExprTyper
  114. object flatOp extends PhaseDependentOps
  115. object naming extends Naming
  116. object replOutput extends ReplOutput
  117. object typerOp extends PhaseDependentOps

Deprecated Value Members

  1. final def setContextClassLoader(): Unit
    Definition Classes
    ReplCore
    Annotations
    @deprecated
    Deprecated

    (Since version 2.12.0) The thread context classloader is now set and restored around execution of REPL line, this method is now a no-op.