StringStream & more stdlib modules support for JS/NimScript (#14095)

* StringStream & more stdlib modules support for JS/NimScript

* change back pegs test in line with #14134

tests/js/tstdlib_various.nim

@@ -0,0 +1,194 @@
+discard """
+output: '''
+abc
+def
+definition
+prefix
+xyz
+def
+definition
+Hi Andreas! How do you feel, Rumpf?
+
+@[0, 2, 1]
+@[1, 0, 2]
+@[1, 2, 0]
+@[2, 0, 1]
+@[2, 1, 0]
+@[2, 0, 1]
+@[1, 2, 0]
+@[1, 0, 2]
+@[0, 2, 1]
+@[0, 1, 2]
+[5]
+[4, 5]
+[3, 4, 5]
+[2, 3, 4, 5]
+[2, 3, 4, 5, 6]
+[1, 2, 3, 4, 5, 6]
+'''
+"""
+
+import
+  critbits, cstrutils, sets, strutils, tables, random, algorithm, ropes,
+  lists, htmlgen, xmltree, strtabs
+
+
+block tcritbits:
+  var r: CritBitTree[void]
+  r.incl "abc"
+  r.incl "xyz"
+  r.incl "def"
+  r.incl "definition"
+  r.incl "prefix"
+  doAssert r.contains"def"
+  #r.del "def"
+
+  for w in r.items:
+    echo w
+  for w in r.itemsWithPrefix("de"):
+    echo w
+
+
+
+block testequivalence:
+  doAssert(toHashSet(@[1,2,3]) <= toHashSet(@[1,2,3,4]), "equivalent or subset")
+  doAssert(toHashSet(@[1,2,3]) <= toHashSet(@[1,2,3]), "equivalent or subset")
+  doAssert((not(toHashSet(@[1,2,3]) <= toHashSet(@[1,2]))), "equivalent or subset")
+  doAssert(toHashSet(@[1,2,3]) <= toHashSet(@[1,2,3,4]), "strict subset")
+  doAssert((not(toHashSet(@[1,2,3]) < toHashSet(@[1,2,3]))), "strict subset")
+  doAssert((not(toHashSet(@[1,2,3]) < toHashSet(@[1,2]))), "strict subset")
+  doAssert((not(toHashSet(@[1,2,3]) == toHashSet(@[1,2,3,4]))), "==")
+  doAssert(toHashSet(@[1,2,3]) == toHashSet(@[1,2,3]), "==")
+  doAssert((not(toHashSet(@[1,2,3]) == toHashSet(@[1,2]))), "==")
+
+
+
+block tformat:
+  echo("Hi $1! How do you feel, $2?\n" % ["Andreas", "Rumpf"])
+
+
+
+block tnilecho:
+  var x = @["1", "", "3"]
+  doAssert $x == """@["1", "", "3"]"""
+
+
+
+block torderedtable:
+  var t = initOrderedTable[int,string]()
+
+  # this tests issue #5917
+  var data = newSeq[int]()
+  for i in 0..<1000:
+    var x = rand(1000)
+    if x notin t: data.add(x)
+    t[x] = "meh"
+
+  # this checks that keys are re-inserted
+  # in order when table is enlarged.
+  var i = 0
+  for k, v in t:
+    doAssert(k == data[i])
+    doAssert(v == "meh")
+    inc(i)
+
+
+
+block tpermutations:
+  var v = @[0, 1, 2]
+  while v.nextPermutation():
+    echo v
+  while v.prevPermutation():
+    echo v
+
+
+block tropes:
+  var
+    r1 = rope("")
+    r2 = rope("123")
+  doAssert r1.len == 0
+  doAssert r2.len == 3
+  doAssert $r1 == ""
+  doAssert $r2 == "123"
+
+  r1.add("123")
+  r2.add("456")
+  doAssert r1.len == 3
+  doAssert r2.len == 6
+  doAssert $r1 == "123"
+  doAssert $r2 == "123456"
+  doAssert $r1[1] == "2"
+  doAssert $r2[2] == "3"
+
+
+block tsinglylinkedring:
+  var r = initSinglyLinkedRing[int]()
+  r.prepend(5)
+  echo r
+  r.prepend(4)
+  echo r
+  r.prepend(3)
+  echo r
+  r.prepend(2)
+  echo r
+  r.append(6)
+  echo r
+  r.prepend(1)
+  echo r
+
+block tsplit:
+  var s = ""
+  for w in split("|abc|xy|z", {'|'}):
+    s.add("#")
+    s.add(w)
+
+  doAssert s == "##abc#xy#z"
+
+block tsplit2:
+  var s = ""
+  for w in split("|abc|xy|z", {'|'}):
+    s.add("#")
+    s.add(w)
+
+  var errored = false
+  try:
+    discard "hello".split("")
+  except AssertionError:
+    errored = true
+  doAssert errored
+
+block txmlgen:
+  var nim = "Nim"
+  doAssert h1(a(href="http://force7.de/nim", nim)) ==
+    "<h1><a href=\"http://force7.de/nim\">Nim</a></h1>"
+
+block txmltree:
+  var x = <>a(href="nim.de", newText("www.nim-test.de"))
+
+  doAssert($x == "<a href=\"nim.de\">www.nim-test.de</a>")
+  doAssert(newText("foo").innerText == "foo")
+  doAssert(newEntity("bar").innerText == "bar")
+  doAssert(newComment("baz").innerText == "")
+
+  let y = newXmlTree("x", [
+    newText("foo"),
+    newXmlTree("y", [
+      newText("bar")
+    ])
+  ])
+  doAssert(y.innerText == "foobar")
+
+
+
+block tcstrutils:
+  let s = cstring "abcdef"
+  doAssert s.startsWith("a")
+  doAssert not s.startsWith("b")
+  doAssert s.endsWith("f")
+  doAssert not s.endsWith("a")
+
+  let a = cstring "abracadabra"
+  doAssert a.startsWith("abra")
+  doAssert not a.startsWith("bra")
+  doAssert a.endsWith("abra")
+  doAssert not a.endsWith("dab")