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. final def !=(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  2. final def ##: Int
    Definition Classes
    AnyRef → Any
  3. def +(other: String): String
    Implicit
    This member is added by an implicit conversion from IMain toany2stringadd[IMain] performed by method any2stringadd in scala.Predef.
    Definition Classes
    any2stringadd
  4. def ->[B](y: B): (IMain, B)
    Implicit
    This member is added by an implicit conversion from IMain toArrowAssoc[IMain] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @inline()
  5. final def ==(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  6. 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.

  7. def allDefinedNames: List[Global.Name]
  8. def allHandlers: collection.immutable.List[(memberHandlers)#MemberHandler]
  9. final def asInstanceOf[T0]: T0
    Definition Classes
    Any
  10. def backticked(s: String): String
  11. 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
  12. def bind[T](name: String, value: T)(implicit arg0: reflect.api.JavaUniverse.TypeTag[T], arg1: ClassTag[T]): Result
  13. def bind(p: NamedParam): Result
    Definition Classes
    IMain → Repl
  14. 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
  15. 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
  16. def classLoader: AbstractFileClassLoader
    Definition Classes
    IMain → Repl
  17. def classOfTerm(id: String): Option[Class[_]]
  18. def classPathString: String
    Definition Classes
    IMain → Repl
  19. def cleanMemberDecl(owner: Global.Symbol, member: Global.Name): Global.Type
  20. def cleanTypeAfterTyper(sym: => Global.Symbol): Global.Type
  21. def clearExecutionWrapper(): Unit
    Definition Classes
    IMain → Repl
  22. def clone(): AnyRef
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.CloneNotSupportedException]) @native()
  23. 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
  24. def compile(line: String, synthetic: Boolean, fatally: Boolean): Either[Result, Request]
  25. def compile(line: String, synthetic: Boolean): Either[Result, Request]
  26. 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
  27. def compileSourcesKeepingRun(sources: SourceFile*): (Boolean, Run)
  28. 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
  29. def compilerClasspath: Seq[URL]
    Definition Classes
    IMain → Repl
  30. def dealiasNonPublic(tp: Global.Type): Global.Type
  31. def debugging[T](msg: String)(res: T): T
  32. def definedSymbolList: collection.immutable.List[Global.Symbol]
  33. def definedTerms: collection.immutable.List[Global.TermName]
  34. def definedTypes: List[String]
    Definition Classes
    IMain → Repl
  35. def directBind[T](name: String, value: T)(implicit arg0: reflect.api.JavaUniverse.TypeTag[T], arg1: ClassTag[T]): Result
  36. def directBind(p: NamedParam): Result
  37. def directBind(name: String, boundType: String, value: Any): Result
  38. final def ensureClassLoader(): Unit
  39. def ensuring(cond: (IMain) => Boolean, msg: => Any): IMain
    Implicit
    This member is added by an implicit conversion from IMain toEnsuring[IMain] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  40. def ensuring(cond: (IMain) => Boolean): IMain
    Implicit
    This member is added by an implicit conversion from IMain toEnsuring[IMain] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  41. def ensuring(cond: Boolean, msg: => Any): IMain
    Implicit
    This member is added by an implicit conversion from IMain toEnsuring[IMain] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  42. def ensuring(cond: Boolean): IMain
    Implicit
    This member is added by an implicit conversion from IMain toEnsuring[IMain] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  43. final def eq(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  44. def equals(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef → Any
  45. def executionWrapper: String
  46. def finalize(): Unit
    Definition Classes
    IMain → AnyRef
  47. def flatPath(sym: Global.Symbol): String
  48. final def getClass(): Class[_ <: AnyRef]
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  49. def getClassIfDefined(path: String): Global.Symbol
  50. def getModuleIfDefined(path: String): Global.Symbol
  51. lazy val global: Global
  52. def hashCode(): Int
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  53. def implicitSymbolsBySource: List[(Global.Symbol, List[Global.Symbol])]
    Definition Classes
    Imports
  54. def implicitsCommandInternal(line: String): (List[String], String)
    Definition Classes
    IMain → Repl
  55. def importHandlers: collection.immutable.List[(memberHandlers)#ImportHandler]
  56. def importsCode(wanted: Set[Global.Name], request: Request, generousImports: Boolean): ComputedImports
    Attributes
    protected
    Definition Classes
    Imports
  57. def importsCommandInternal(tokens: List[String]): List[String]
    Definition Classes
    IMain → Repl
  58. def initializeCompiler(): Boolean
    Definition Classes
    IMain → Repl
  59. def initializeComplete: Boolean
    Definition Classes
    IMain → Repl
  60. def interpret(line: String, synthetic: Boolean): Result
    Definition Classes
    IMain → Repl
  61. 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
  62. 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
  63. def interpretSynthetic(line: String): Result
  64. lazy val isClassBased: Boolean
  65. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  66. def isPackaged(line: String): Boolean

    Does code start with a package definition?

    Does code start with a package definition?

    Definition Classes
    IMain → Repl
  67. def kindCommandInternal(typeString: String, verbose: Boolean): String
    Definition Classes
    IMain → Repl
  68. def languageWildcardHandlers: collection.immutable.List[(memberHandlers)#ImportHandler]
    Definition Classes
    Imports
  69. def lastRequest: Request
  70. def lastWarnings: List[(Global.Position, String)]
    Definition Classes
    IMain → Repl
  71. lazy val memberHandlers: MemberHandlers { val intp: IMain.this.type }
  72. 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
  73. def nameToCode(s: String): String
  74. def namedDefinedTerms: List[String]
    Definition Classes
    IMain → Repl
  75. def namedParam[T](name: String, value: T)(implicit arg0: reflect.api.JavaUniverse.TypeTag[T], arg1: ClassTag[T]): NamedParam
    Definition Classes
    IMain → Repl
  76. final def ne(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  77. 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
  78. final def notify(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  79. final def notifyAll(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  80. def onlyTerms(xs: List[Global.Name]): List[Global.TermName]
    Attributes
    protected
  81. def onlyTypes(xs: List[Global.Name]): List[Global.TypeName]
    Attributes
    protected
  82. def originalPath(sym: Global.Symbol): String
  83. def originalPath(name: Global.Name): String
  84. def originalPath(name: String): String
    Definition Classes
    IMain → Repl
  85. def outputDir: ReplDir
    Definition Classes
    IMain → Repl
  86. def parentClassLoader: ClassLoader

    Parent classloader.

    Parent classloader. Overridable.

    Attributes
    protected
  87. def parse(line: String, fatally: Boolean): Either[Result, (List[Global.Tree], Global.Position, BatchSourceFile)]
  88. def parse(line: String): Either[Result, (List[Global.Tree], Global.Position, BatchSourceFile)]

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

  89. 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
  90. lazy val power: Power[StdReplVals]
    Definition Classes
    IMain → Repl
  91. 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
  92. def prevRequestList: collection.immutable.List[Request]
  93. def quietBind(p: NamedParam): Result
    Definition Classes
    IMain → Repl
  94. def quietRun(code: String): Result
    Definition Classes
    IMain → Repl
  95. val readInstanceName: String
  96. def readRootPath(readPath: String): Global.Symbol
  97. def rebind(p: NamedParam): Result
  98. def recordRequest(req: Request): Unit
  99. def replClass: Class[_]
    Attributes
    protected
  100. def replScope: Global.Scope
  101. def replStrings: ReplStrings
  102. val reporter: ReplReporter
    Definition Classes
    IMain → Repl
  103. def requestDefining(name: String): Option[Request]
    Definition Classes
    IMain → Repl
  104. def reset(): Unit

    Reset this interpreter, forgetting all user-specified requests.

    Reset this interpreter, forgetting all user-specified requests.

    Definition Classes
    IMain → Repl
  105. def resetClassLoader(): Unit
  106. def runtimeClassAndTypeOfTerm(id: String): Option[(Class[_], Global.Type)]
  107. def runtimeMirror: Mirror
  108. def runtimeTypeOfTerm(id: String): Global.Type
  109. def setExecutionWrapper(code: String): Unit
    Definition Classes
    IMain → Repl
  110. val settings: Settings
    Definition Classes
    IMain → Repl
  111. def showDirectory: String
    Definition Classes
    IMain → Repl
  112. def symbolDefString(sym: Global.Symbol): String
  113. def symbolOfIdent(id: String): Global.Symbol
  114. def symbolOfLine(code: String): Global.Symbol
  115. def symbolOfName(id: Global.Name): Global.Symbol
  116. def symbolOfTerm(id: String): Global.Symbol
  117. def symbolOfType(id: String): Global.Symbol
  118. final def synchronized[T0](arg0: => T0): T0
    Definition Classes
    AnyRef
  119. def toString(): String
    Definition Classes
    AnyRef → Any
  120. def tokenize(line: String): List[TokenData]
    Definition Classes
    IMain → Repl
  121. def translateEnclosingClass(n: String): Option[String]
    Definition Classes
    IMain → Repl
  122. def translateOriginalPath(p: String): String
  123. def translatePath(path: String): Option[String]
    Definition Classes
    IMain → Repl
  124. 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.

  125. 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.

  126. 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
  127. def typeOfExpression(expr: String, silent: Boolean = true): Global.Type
  128. def typeOfTerm(id: String): Global.Type
  129. def typeToCode(s: String): String
  130. def unqualifiedIds: List[String]
  131. def updateSettings(arguments: List[String]): Boolean
    Definition Classes
    IMain → Repl
  132. def userSetSettings: List[Setting]
    Definition Classes
    IMain → Repl
  133. def valueOfTerm(id: String): Option[Any]
    Definition Classes
    IMain → Repl
  134. def visibleSettings: List[Setting]
    Definition Classes
    IMain → Repl
  135. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  136. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  137. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException]) @native()
  138. def withLabel[A](temp: String)(body: => A): A
    Definition Classes
    IMain → Repl
  139. def withSuppressedSettings(body: => Unit): Unit
    Definition Classes
    IMain → Repl
  140. def withoutWarnings[T](body: => T): T
  141. object deconstruct extends StructuredTypeStrings
  142. object exprTyper extends ExprTyper
  143. object flatOp extends PhaseDependentOps
  144. object naming extends Naming
  145. object replOutput extends ReplOutput
  146. object typerOp extends PhaseDependentOps

Deprecated Value Members

  1. def formatted(fmtstr: String): String
    Implicit
    This member is added by an implicit conversion from IMain toStringFormat[IMain] performed by method StringFormat in scala.Predef.
    Definition Classes
    StringFormat
    Annotations
    @deprecated @inline()
    Deprecated

    (Since version 2.12.16) Use formatString.format(value) instead of value.formatted(formatString), or use the f"" string interpolator. In Java 15 and later, formatted resolves to the new method in String which has reversed parameters.

  2. 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.

  3. def →[B](y: B): (IMain, B)
    Implicit
    This member is added by an implicit conversion from IMain toArrowAssoc[IMain] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @deprecated
    Deprecated

    (Since version 2.13.0) Use -> instead. If you still wish to display it as one character, consider using a font with programming ligatures such as Fira Code.

Inherited from Closeable

Inherited from AutoCloseable

Inherited from PresentationCompilation

Inherited from Imports

Inherited from Repl

Inherited from ReplCore

Inherited from AnyRef

Inherited from Any

Inherited by implicit conversion any2stringadd fromIMain to any2stringadd[IMain]

Inherited by implicit conversion StringFormat fromIMain to StringFormat[IMain]

Inherited by implicit conversion Ensuring fromIMain to Ensuring[IMain]

Inherited by implicit conversion ArrowAssoc fromIMain to ArrowAssoc[IMain]

Ungrouped