test removing dollar for objects out of system (#20242)

* test removing dollar for objects out of system

* test & fixes

* fix bootstrap

* use nimPreviewSlimSystem, test stdlib category

* fix test

lib/system/dollars.nim

@@ -3,7 +3,7 @@ runnableExamples:
   assert $0.1 == "0.1"
   assert $(-2*3) == "-6"
 
-import std/private/digitsutils
+import std/private/[digitsutils, miscdollars]
 import system/formatfloat
 export addFloat
 
@@ -69,24 +69,7 @@ proc `$`*(t: typedesc): string {.magic: "TypeTrait".}
   ##   doAssert $(typeof("Foo")) == "string"
   ##   static: doAssert $(typeof(@['A', 'B'])) == "seq[char]"
 
-when defined(nimHasIsNamedTuple):
-  proc isNamedTuple(T: typedesc): bool {.magic: "TypeTrait".}
-else:
-  # for bootstrap; remove after release 1.2
-  proc isNamedTuple(T: typedesc): bool =
-    # Taken from typetraits.
-    when T isnot tuple: result = false
-    else:
-      var t: T
-      for name, _ in t.fieldPairs:
-        when name == "Field0":
-          return compiles(t.Field0)
-        else:
-          return true
-      return false
-
-
-proc `$`*[T: tuple|object](x: T): string =
+proc `$`*[T: tuple](x: T): string =
   ## Generic `$` operator for tuples that is lifted from the components
   ## of `x`. Example:
   ##
@@ -94,28 +77,11 @@ proc `$`*[T: tuple|object](x: T): string =
   ##   $(23, 45) == "(23, 45)"
   ##   $(a: 23, b: 45) == "(a: 23, b: 45)"
   ##   $() == "()"
-  result = "("
-  const isNamed = T is object or isNamedTuple(T)
-  var count {.used.} = 0
-  for name, value in fieldPairs(x):
-    if count > 0: result.add(", ")
-    when isNamed:
-      result.add(name)
-      result.add(": ")
-    count.inc
-    when compiles($value):
-      when value isnot string and value isnot seq and compiles(value.isNil):
-        if value.isNil: result.add "nil"
-        else: result.addQuoted(value)
-      else:
-        result.addQuoted(value)
-    else:
-      result.add("...")
-  when not isNamed:
-    if count == 1:
-      result.add(",") # $(1,) should print as the semantically legal (1,)
-  result.add(")")
+  tupleObjectDollar(result, x)
 
+when not defined(nimPreviewSlimSystem):
+  import std/objectdollar
+  export objectdollar
 
 proc collectionToString[T](x: T, prefix, separator, suffix: string): string =
   result = prefix