feat(builtin): Ellipsis (ast syntax ... is sup too)

Author: litlighilit

Objects/pyobjectBase.nim

@@ -10,7 +10,7 @@ type
     NULL,
     Object,
     None,
-    NotImplemented,
+    Ellipsis,
     BaseError, # exception
     Int,
     Float,

Objects/sliceobject.nim

@@ -70,3 +70,18 @@ proc getSliceItems*(slice: PySliceObject, src, dest: ptr seq[PyObject]): PyObjec
       dest[].add(src[][start])
       start += step
   pyNone
+
+declarePyType Ellipsis(tpToken):
+  discard
+
+let pyEllipsis* = newPyEllipsisSimple()
+
+proc dollar(self: PyEllipsisObject): string = "Ellipsis"
+method `$`*(self: PyEllipsisObject): string =
+  self.dollar
+
+implEllipsisMagic repr:
+  newPyString self.dollar
+
+implEllipsisMagic New(tp: PyObject):
+  return pyEllipsis

Python/ast.nim

@@ -7,7 +7,10 @@ import strformat
 
 import asdl
 import ../Parser/[token, parser]
-import ../Objects/[pyobject, noneobject, numobjects, boolobjectImpl, stringobjectImpl]
+import ../Objects/[pyobject, noneobject,
+  numobjects, boolobjectImpl, stringobjectImpl,
+  sliceobject  # pyEllipsis
+  ]
 import ../Utils/[utils, compat]
 
 
@@ -1053,8 +1056,10 @@ ast atom, [AsdlExpr]:
   of Token.None:
     result = newAstConstant(pyNone)
 
+  of Token.Ellipsis:
+    result = newAstConstant(pyEllipsis)
   else:
-    raiseSyntaxError("ellipsis not implemented")
+    unreachable()
 
   assert result != nil
   setNo(result, parseNode.children[0])

Python/bltinmodule.nim

@@ -107,6 +107,7 @@ implBltinFunc buildClass(funcObj: PyFunctionObject, name: PyStrObject), "__build
 
 
 registerBltinObject("NotImplemented", pyNotImplemented)
+registerBltinObject("Ellipsis", pyEllipsis)
 registerBltinObject("None", pyNone)
 registerBltinObject("type", pyTypeObjectType)
 registerBltinObject("range", pyRangeObjectType)