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/* NSC -- new Scala compiler
* Copyright 2005-2013 LAMP/EPFL
* @author Paul Phillips
*/
package scala.tools.nsc
package interpreter
trait ExprTyper {
val repl: IMain
import repl._
import global.{ reporter => _, Import => _, _ }
import naming.freshInternalVarName
private def doInterpret(code: String): IR.Result = {
// interpret/interpretSynthetic may change the phase, which would have unintended effects on types.
val savedPhase = phase
try interpretSynthetic(code) finally phase = savedPhase
}
def symbolOfLine(code: String): Symbol = {
def asExpr(): Symbol = {
val name = freshInternalVarName()
// Typing it with a lazy val would give us the right type, but runs
// into compiler bugs with things like existentials, so we compile it
// behind a def and strip the NullaryMethodType which wraps the expr.
val line = "def " + name + " = " + code
doInterpret(line) match {
case IR.Success =>
val sym0 = symbolOfTerm(name)
// drop NullaryMethodType
sym0.cloneSymbol setInfo exitingTyper(sym0.tpe_*.finalResultType)
case _ => NoSymbol
}
}
def asDefn(): Symbol = {
val old = repl.definedSymbolList.toSet
doInterpret(code) match {
case IR.Success =>
repl.definedSymbolList filterNot old match {
case Nil => NoSymbol
case sym :: Nil => sym
case syms => NoSymbol.newOverloaded(NoPrefix, syms)
}
case _ => NoSymbol
}
}
def asError(): Symbol = {
doInterpret(code)
NoSymbol
}
beSilentDuring(asExpr()) orElse beSilentDuring(asDefn()) orElse asError()
}
private var typeOfExpressionDepth = 0
def typeOfExpression(expr: String, silent: Boolean = true): Type = {
if (typeOfExpressionDepth > 2) {
repldbg("Terminating typeOfExpression recursion for expression: " + expr)
return NoType
}
typeOfExpressionDepth += 1
// Don't presently have a good way to suppress undesirable success output
// while letting errors through, so it is first trying it silently: if there
// is an error, and errors are desired, then it re-evaluates non-silently
// to induce the error message.
try beSilentDuring(symbolOfLine(expr).tpe) match {
case NoType if !silent => symbolOfLine(expr).tpe // generate error
case tpe => tpe
}
finally typeOfExpressionDepth -= 1
}
// This only works for proper types.
def typeOfTypeString(typeString: String): Type = {
def asProperType(): Option[Type] = {
val name = freshInternalVarName()
val line = "def %s: %s = ???" format (name, typeString)
doInterpret(line) match {
case IR.Success =>
val sym0 = symbolOfTerm(name)
Some(sym0.asMethod.returnType)
case _ => None
}
}
beSilentDuring(asProperType()) getOrElse NoType
}
}
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