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package scala.tools.nsc
package interactive
import util.{SourceFile, BatchSourceFile, RangePosition}
import collection.mutable.ArrayBuffer
import reflect.internal.Chars.isLineBreakChar
trait ScratchPadMaker { self: Global =>
import definitions._
private case class Patch(offset: Int, text: String)
private class Patcher(contents: Array[Char], endOffset: Int) extends Traverser {
var objectName: String = ""
private val patches = new ArrayBuffer[Patch]
private val toPrint = new ArrayBuffer[String]
private var skipped = 0
private var resNum: Int = -1
private def nextRes(): String = {
resNum += 1
"res$"+resNum
}
private def nameType(name: String, tpe: Type): String = name+": "+tpe
private def nameType(sym: Symbol): String = nameType(sym.name.toString, sym.tpe)
private def literal(str: String) = "\"\"\""+str+"\"\"\""
private def applyPendingPatches(offset: Int) = {
if (skipped == 0) patches += Patch(offset, "import scala.tools.nsc.scratchpad.Executor._; ")
for (msg <- toPrint) patches += Patch(offset, ";System.out.println("+msg+")")
toPrint.clear()
}
private def addSkip(stat: Tree): Unit = {
if (stat.pos.start > skipped) applyPendingPatches(stat.pos.start)
if (stat.pos.start >= endOffset)
patches += Patch(stat.pos.start, ";$stop()")
var end = stat.pos.end
if (end > skipped) {
while (end < contents.length && !(isLineBreakChar(contents(end)))) end += 1
patches += Patch(stat.pos.start, ";$skip("+(end-skipped)+"); ")
skipped = end
}
}
private def addSandbox(expr: Tree) = {}
// patches += (Patch(expr.pos.start, "sandbox("), Patch(expr.pos.end, ")"))
private def resultString(prefix: String, expr: String) =
literal(prefix + " = ") + " + $show(" + expr + ")"
private def traverseStat(stat: Tree) =
if (stat.pos.isInstanceOf[RangePosition]) {
stat match {
case ValDef(_, _, _, rhs) =>
addSkip(stat)
if (stat.symbol.isLazy)
toPrint += literal(nameType(stat.symbol) + " = <lazy>")
else if (!stat.symbol.isSynthetic) {
addSandbox(rhs)
toPrint += resultString(nameType(stat.symbol), stat.symbol.name.toString)
}
case DefDef(_, _, _, _, _, _) =>
addSkip(stat)
toPrint += literal(nameType(stat.symbol))
case Annotated(_, arg) =>
traverse(arg)
case DocDef(_, defn) =>
traverse(defn)
case _ =>
if (stat.isTerm) {
addSkip(stat)
if (stat.tpe.typeSymbol == UnitClass) {
addSandbox(stat)
} else {
val resName = nextRes()
val dispResName = resName filter ('$' != _)
patches += Patch(stat.pos.start, "val " + resName + " = ")
addSandbox(stat)
toPrint += resultString(nameType(dispResName, stat.tpe), resName)
}
}
}
}
override def traverse(tree: Tree): Unit = tree match {
case PackageDef(_, _) =>
super.traverse(tree)
case ModuleDef(_, name, Template(_, _, body)) =>
if (objectName.length == 0 /* objectName.isEmpty does not compile on Java 5 due to ambiguous implicit conversions: augmentString, stringToTermName */)
objectName = tree.symbol.fullName
body foreach traverseStat
applyPendingPatches(skipped)
case _ =>
}
/** The patched text.
* @require traverse is run first
*/
def result: Array[Char] = {
val reslen = contents.length + (patches map (_.text.length)).sum
val res = Array.ofDim[Char](reslen)
var lastOffset = 0
var from = 0
var to = 0
for (Patch(offset, text) <- patches) {
val delta = offset - lastOffset
assert(delta >= 0)
Array.copy(contents, from, res, to, delta)
from += delta
to += delta
lastOffset = offset
text.copyToArray(res, to)
to += text.length
}
assert(contents.length - from == reslen - to)
Array.copy(contents, from, res, to, contents.length - from)
res
}
}
/** Compute an instrumented version of a sourcefile.
* @param source The given sourcefile.
* @param line The line up to which results should be printed, -1 = whole document.
* @return A pair consisting of
* - the fully qualified name of the first top-level object definition in the file.
* or "" if there are no object definitions.
* - the text of the instrumented program which, when run,
* prints its output and all defined values in a comment column.
*/
protected def instrument(source: SourceFile, line: Int): (String, Array[Char]) = {
val tree = typedTree(source, true)
val endOffset = if (line < 0) source.length else source.lineToOffset(line + 1)
val patcher = new Patcher(source.content, endOffset)
patcher.traverse(tree)
(patcher.objectName, patcher.result)
}
}
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