Improved collection-to-string behavior (#6825)

tests/collections/tcollections_to_string.nim

@@ -0,0 +1,106 @@
+discard """
+  exitcode: 0
+  output: ""
+"""
+import sets
+import tables
+import deques
+import lists
+import critbits
+
+# Tests for tuples
+doAssert $(1, 2, 3) == "(Field0: 1, Field1: 2, Field2: 3)"
+doAssert $("1", "2", "3") == """(Field0: "1", Field1: "2", Field2: "3")"""
+doAssert $('1', '2', '3') == """(Field0: '1', Field1: '2', Field2: '3')"""
+
+# Tests for seqs
+doAssert $(@[1, 2, 3]) == "@[1, 2, 3]"
+doAssert $(@["1", "2", "3"]) == """@["1", "2", "3"]"""
+doAssert $(@['1', '2', '3']) == """@['1', '2', '3']"""
+
+# Tests for sets
+doAssert $(toSet([1])) == "{1}"
+doAssert $(toSet(["1"])) == """{"1"}"""
+doAssert $(toSet(['1'])) == """{'1'}"""
+doAssert $(toOrderedSet([1, 2, 3])) == "{1, 2, 3}"
+doAssert $(toOrderedSet(["1", "2", "3"])) == """{"1", "2", "3"}"""
+doAssert $(toOrderedSet(['1', '2', '3'])) == """{'1', '2', '3'}"""
+
+# Tests for tables
+doAssert $({1: "1", 2: "2"}.toTable) == """{1: "1", 2: "2"}"""
+doAssert $({"1": 1, "2": 2}.toTable) == """{"1": 1, "2": 2}"""
+
+# Tests for deques
+block:
+  var d = initDeque[int]()
+  d.addLast(1)
+  doAssert $d == "[1]"
+block:
+  var d = initDeque[string]()
+  d.addLast("1")
+  doAssert $d == """["1"]"""
+block:
+  var d = initDeque[char]()
+  d.addLast('1')
+  doAssert $d == "['1']"
+
+# Tests for lists
+block:
+  var l = initDoublyLinkedList[int]()
+  l.append(1)
+  l.append(2)
+  l.append(3)
+  doAssert $l == "[1, 2, 3]"
+block:
+  var l = initDoublyLinkedList[string]()
+  l.append("1")
+  l.append("2")
+  l.append("3")
+  doAssert $l == """["1", "2", "3"]"""
+block:
+  var l = initDoublyLinkedList[char]()
+  l.append('1')
+  l.append('2')
+  l.append('3')
+  doAssert $l == """['1', '2', '3']"""
+
+# Tests for critbits
+block:
+  var t: CritBitTree[int]
+  t["a"] = 1
+  doAssert $t == "{a: 1}"
+block:
+  var t: CritBitTree[string]
+  t["a"] = "1"
+  doAssert $t == """{a: "1"}"""
+block:
+  var t: CritBitTree[char]
+  t["a"] = '1'
+  doAssert $t == "{a: '1'}"
+
+
+# Test escaping behavior
+block:
+  var s = ""
+  s.addQuoted('\0')
+  s.addQuoted('\31')
+  s.addQuoted('\127')
+  s.addQuoted('\255')
+  doAssert s == "'\\x00''\\x1F''\\x7F''\\xFF'"
+block:
+  var s = ""
+  s.addQuoted('\\')
+  s.addQuoted('\'')
+  s.addQuoted('\"')
+  doAssert s == """'\\''\'''\"'"""
+
+# Test customized element representation
+type CustomString = object
+
+proc addQuoted(s: var string, x: CustomString) =
+  s.add("<CustomString>")
+
+block:
+  let s = @[CustomString()]
+  doAssert $s == "@[<CustomString>]"
+