如何列出范围/环境/绑定中所有"变量"（而不仅仅是变量）的名称和/或值？
为了澄清，在程序/脚本的中间或REPL的某个时刻，我需要（1）生成一个列表或（2）打印Scala语句可以访问的所有实体的列表。
这个问题可以广义解释，但例如REPL对具有作用域绑定的javax.script有一些支持：
$ scala
Welcome to Scala version 2.11.2 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_11).
Type in expressions to have them evaluated.
Type :help for more information.
scala> val e = $intp.asInstanceOf[javax.script.ScriptEngine]
e: javax.script.ScriptEngine = scala.tools.nsc.interpreter.ILoop$ILoopInterpreter@2b71fc7e
scala> e.getContext
res0: javax.script.ScriptContext = javax.script.SimpleScriptContext@63c12fb0
scala> e.getContext.getScopes
res1: java.util.List[Integer] = [100, 200]
scala> e.getContext.getBindings(100)
res2: javax.script.Bindings = {}
REPL本身保留了一个可以查询的范围，表示自动导入当前脚本行的当前会话的历史：
scala> $intp.replScope
res3: $intp.global.Scope = Scopes(value $intp, value e, value res0, value res1, value res2)
也可以使用REPL的完成机制：
scala> :power
** Power User mode enabled - BEEP WHIR GYVE **
** :phase has been set to 'typer'. **
** scala.tools.nsc._ has been imported **
** global._, definitions._ also imported **
** Try :help, :vals, power.<tab> **
scala> reader.completion
res4: scala.tools.nsc.interpreter.Completion = scala.tools.nsc.interpreter.JLineCompletion@68b7bdcb
scala> res4.completer.complete("",0)
res6: scala.tools.nsc.interpreter.Completion.Candidates = Candidates(0,List($intp, $ires0, $ires1, $ires10, $ires11, $ires12, $ires13, $ires14, $ires15, $ires16, $ires17, $ires18, $ires2, $ires3, $ires4, $ires5, $ires6, $ires7, $ires8, $ires9, $r, AND, BLOCK, CASE, DEFAULT, FALSE, IF, LIT, NEW, NOT, NULL, REF, SOME, SelectStart, TRUE, TRY, UNIT, ZERO, analyzer, classOf, completion, e, fn, global, history, intp, isettings, lastRequest, mkTreeFromSelectStart, mkTreeMethods, mkTreeMethodsFromSelectStart, mkTreeMethodsFromSymbol, nullSafe, phased, power, r, reader, repl, replImplicits, res0, res1, res2, res3, res4, returning, scala$tools$nsc$ast$TreeDSL$CODE$$$outer, treedsl, typed, typer, vals))
scala>
REPL控制台中的一个选项卡提供了自动完成功能，它在这里显示了我当前目录中的所有垃圾，默认情况下在类路径上：
$ scala
Welcome to Scala version 2.11.2 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_11).
Type in expressions to have them evaluated.
Type :help for more information.
scala>
$intp broken enumtest inheritthewind maker oracle sbtbomb thingy
P bumper erased inlined mangled orelse scala throwgen
Q butwhen exh inliner mapeach org scallop thrownull
SO22581163 bytype eyeshadow inner maqicode othercase scrap tiles
_root_ callbacks fany inputcheck matchprim out scripts timezone
a capture featureless intcake maybeamb overdone searchme tmp
abjectfuture cce ff interp maykov overnullary selfpub toString
absval cdtest fielding interpat metamac pathmaker seqto tops
adaptation charmatch filloval intpbind mkarray peasy serialmigration trial
akka choosy filrdr intupolated mksym pet serious tribool
algedu classOf findwidgets invokeFrom modtest petconfig shapelessed tricks
angeldance classmatch finf isInstanceOf myanno phyl simple-swing trivial
annee classy fixedimp isanon mydays pickit singleton tryxform
annie cmpprs fixes isfun myintp pimpin slider tstest
annoconst coltfred fixme isscala mypkg pkginvoke slow typeref
annot com flib java mypriv plugincp smtest tztest
anymember compilit foodir javafx nestedmain plugs sobral unapplynull
anything convprs fooplus javax netscape pointers somatch unavail
applied copier for29 jbyte newfrom pointopt some_package unensured
arrow corner formac jdk nextcompleted pos sortitout unused
asInstanceOf counted ftw jex niolock poster sounds updater
atrait countints funk jext noany pow specbug valdef
autoenum cr funkstr jline noapp preferthunk speck vec
auxctor ctag futfilter jmap nodep prettycase splitat version
bad-scales curtest futuremap jover nofeature primover stale vowelshift
badXlint cyclic fval jperms nofuture printer statik w
badaccess dbadd gline junk noimp privctor str2int warnadapt
badbob default-tparam global k noinline privover strtyp weakerr
badgeneric delayed goodbye kcharex nointerp procked structural-return welper
badimp delayedsignal gr keptstar nonl protcase stupid whose
badinherit delineate grapher kmap norec protval succinctly widgets
badmap demoapi groupby lazyparadox nosehorn publicity sun wrappedarray
badmatch dep guiced lazyside nothingannot q superduper wtf
badover doc guy lazysplit ns qqparms sxema x
badoverride dockable halfinterval lib nts quickly syncd xmladd
badpath dosth here liner nullgroup quoterep syshook xmlex
badpkg doublearrow hidden linetest nullpair rawj t1 xmlregex
badseal dummyonly hiddenimport linted nulltype raws t1807 xmlreplace
badstrimp dynospec id linty nummaker reader t5148 xmlsub
badvargs earlier imparted lit off reflectenum t5589 xmlt
badvol eatery imparter littlecake oiler5 replslow t7121 xxx
bigmethod email impctx looker old-and-blue repro t7775 zed
binder empty impless lookit oldname required t8433
biterpolator emptypackage impmag lookup om sample-foo tabpane
blocking enclosing imptest loopy oneq samplewarn taggedparam
blownfuture enclosingcls imptrait macinfer oops saver target
bounded enpatch include macvar optdate sbt-test teachers
scala>
这在运行时是不可能做到的，至少不是你想要的方式，因为JVM并没有被组织成一个在每次语句后更新的巨大符号表，你可以随时查询并找到你所称的命名实体（我认为这在各种语言和环境中都是正确的）。
您可以尝试查询确实组织为表的东西，比如类/接口的方法，但在进行查询之前，您必须知道类的完全限定名称。举个简单的例子，根据类加载的工作方式，JVM甚至无法枚举您可以创建的类，因为新的类可以动态创建，也可以从某个存储库中检索。再举一个例子，import在运行时根本不存在。。。
你必须缩小你的要求。例如，如果您以REPL为目标，您可能能够（但需要付出巨大的努力）对其进行修改，以破坏其内部数据结构。类似地，如果你以脚本为目标并可以访问源代码，理论上你可以用一个能完成你需要的工作的插件来修改编译器。请注意，我只提到了这些事情，但永远不会考虑自己做这样的事情，因为这需要付出很多努力，我看不出有什么真正的需要。