指定Toolbox解析的AST的源

Question

我正在使用Scala的编译器API中的工具箱将代码编译成AST，然后对它们进行分解/拼接，并将它们组合成一棵树。为了调试目的，我试图跟踪哪个节点来自哪个源代码。

示例：

import scala.reflect.runtime.universe._
import scala.tools.reflect.ToolBox

// obtain toolbox
val tb = runtimeMirror(this.getClass.getClassLoader).mkToolBox()
// get and parse source code from file
val myCode = scala.io.Source.fromFile("MyCode.scala").mkString
val myTree = tb.parse(myCode)
// get and parse dynamically-generated source code
val genCode = com.example.CodeGenerator.gimmeCode
val genTree = tb.parse(genCode)
// get and parse source code from a string literal
val literalCode = """println("to life, the universe, and everything")"""
val literalTree = tb.parse(literalCode)
// an over-simplified combination of the trees
val frankensteinsTree = q"$myTree;$genTree;$literalTree"

// walk the tree an print the source of each element
val traverser = new Traverser() {

  override def traverse(tree: Tree): Unit = {

    println("This node originated from " + tree.pos.source)
    super.traverse(tree)
  }
}

// the root element prints "This node originated from <no source file>"
// the rest print "This node originated from <toolbox>"
traverser.traverse(frankensteinsTree)

在上面的示例中，除了根节点之外，所有其他节点都显示源是<toolbox>。(根节点表示<no source file>。)在剖析和重新组合它们之前，是否有一种方法可以指定tree.pos.source来识别每个节点的实际来源？

Answer 1

不，目前(从2020年到05-28年)不能这样做。

Answer 2

你是说

println("Position is:  " + "MyCode" + tree.pos.toString.stripPrefix("source-<toolbox>"))
// Position is:  MyCode,line-1,offset=7

试一试

val p = tree.pos
val pointMessage  = if (p.point > p.source.length) "out-of-bounds-" else "offset="
println(
  s"source-${p.source.file.canonicalPath},INSERT WHAT YOU WANT,line-${p.line},$pointMessage${p.point}"
) // source-<toolbox>,INSERT WHAT YOU WANT,line-1,offset=7