Patch #1550786: ellipsis literal.

Author: birkenfeld

Doc/lib/libconsts.tex

@@ -26,6 +26,8 @@ \section{Built-in Constants}
 \end{datadesc}
 
 \begin{datadesc}{Ellipsis}
-  Special value used in conjunction with extended slicing syntax.
+  The same as \code{...}.
+  Special value used mostly in conjunction with extended slicing syntax
+  for user-defined container data types.
   % XXX Someone who understands extended slicing should fill in here.
 \end{datadesc}

Doc/lib/libstdtypes.tex

@@ -2004,12 +2004,12 @@ \subsection{The Null Object \label{bltin-null-object}}
 
 \subsection{The Ellipsis Object \label{bltin-ellipsis-object}}
 
-This object is used by extended slice notation (see the
+This object is mostly used by extended slice notation (see the
 \citetitle[../ref/ref.html]{Python Reference Manual}).  It supports no
 special operations.  There is exactly one ellipsis object, named
 \constant{Ellipsis} (a built-in name).
 
-It is written as \code{Ellipsis}.
+It is written as \code{Ellipsis} or \code{...}.
 
 \subsection{Boolean Values}
 

Doc/ref/ref3.tex

@@ -148,9 +148,8 @@ \section{The standard type hierarchy\label{types}}
 
 \item[Ellipsis]
 This type has a single value.  There is a single object with this value.
-This object is accessed through the built-in name \code{Ellipsis}.
-It is used to indicate the presence of the \samp{...} syntax in a
-slice.  Its truth value is true.
+This object is accessed through the literal \code{...} or the
+built-in name \code{Ellipsis}.  Its truth value is true.
 \obindex{Ellipsis}
 
 \item[Numbers]

Doc/ref/ref5.tex

@@ -411,8 +411,7 @@ \subsection{Slicings\label{slicings}}
 contains at least one comma, the key is a tuple containing the
 conversion of the slice items; otherwise, the conversion of the lone
 slice item is the key.  The conversion of a slice item that is an
-expression is that expression.  The conversion of an ellipsis slice
-item is the built-in \code{Ellipsis} object.  The conversion of a
+expression is that expression.  The conversion of a
 proper slice is a slice object (see section \ref{types}) whose
 \member{start}, \member{stop} and \member{step} attributes are the
 values of the expressions given as lower bound, upper bound and

Grammar/Grammar

@@ -101,13 +101,13 @@ power: atom trailer* ['**' factor]
 atom: ('(' [yield_expr|testlist_gexp] ')' |
        '[' [listmaker] ']' |
        '{' [dictsetmaker] '}' |
-       NAME | NUMBER | STRING+)
+       NAME | NUMBER | STRING+ | '.' '.' '.')
 listmaker: test ( list_for | (',' test)* [','] )
 testlist_gexp: test ( gen_for | (',' test)* [','] )
 lambdef: 'lambda' [varargslist] ':' test
 trailer: '(' [arglist] ')' | '[' subscriptlist ']' | '.' NAME
 subscriptlist: subscript (',' subscript)* [',']
-subscript: '.' '.' '.' | test | [test] ':' [test] [sliceop]
+subscript: test | [test] ':' [test] [sliceop]
 sliceop: ':' [test]
 exprlist: expr (',' expr)* [',']
 testlist: test (',' test)* [',']

Include/Python-ast.h

@@ -180,8 +180,9 @@ struct _stmt {
 enum _expr_kind {BoolOp_kind=1, BinOp_kind=2, UnaryOp_kind=3, Lambda_kind=4,
                   IfExp_kind=5, Dict_kind=6, Set_kind=7, ListComp_kind=8,
                   GeneratorExp_kind=9, Yield_kind=10, Compare_kind=11,
-                  Call_kind=12, Num_kind=13, Str_kind=14, Attribute_kind=15,
-                  Subscript_kind=16, Name_kind=17, List_kind=18, Tuple_kind=19};
+                  Call_kind=12, Num_kind=13, Str_kind=14, Ellipsis_kind=15,
+                  Attribute_kind=16, Subscript_kind=17, Name_kind=18,
+                  List_kind=19, Tuple_kind=20};
 struct _expr {
         enum _expr_kind kind;
         union {
@@ -289,7 +290,7 @@ struct _expr {
         int col_offset;
 };
 
-enum _slice_kind {Ellipsis_kind=1, Slice_kind=2, ExtSlice_kind=3, Index_kind=4};
+enum _slice_kind {Slice_kind=1, ExtSlice_kind=2, Index_kind=3};
 struct _slice {
         enum _slice_kind kind;
         union {
@@ -408,6 +409,7 @@ expr_ty Call(expr_ty func, asdl_seq * args, asdl_seq * keywords, expr_ty
              *arena);
 expr_ty Num(object n, int lineno, int col_offset, PyArena *arena);
 expr_ty Str(string s, int lineno, int col_offset, PyArena *arena);
+expr_ty Ellipsis(int lineno, int col_offset, PyArena *arena);
 expr_ty Attribute(expr_ty value, identifier attr, expr_context_ty ctx, int
                   lineno, int col_offset, PyArena *arena);
 expr_ty Subscript(expr_ty value, slice_ty slice, expr_context_ty ctx, int
@@ -418,7 +420,6 @@ expr_ty List(asdl_seq * elts, expr_context_ty ctx, int lineno, int col_offset,
              PyArena *arena);
 expr_ty Tuple(asdl_seq * elts, expr_context_ty ctx, int lineno, int col_offset,
               PyArena *arena);
-slice_ty Ellipsis(PyArena *arena);
 slice_ty Slice(expr_ty lower, expr_ty upper, expr_ty step, PyArena *arena);
 slice_ty ExtSlice(asdl_seq * dims, PyArena *arena);
 slice_ty Index(expr_ty value, PyArena *arena);

Lib/compiler/ast.py

@@ -427,19 +427,6 @@ def getChildNodes(self):
     def __repr__(self):
         return "Div((%s, %s))" % (repr(self.left), repr(self.right))
 
-class Ellipsis(Node):
-    def __init__(self, lineno=None):
-        self.lineno = lineno
-
-    def getChildren(self):
-        return ()
-
-    def getChildNodes(self):
-        return ()
-
-    def __repr__(self):
-        return "Ellipsis()"
-
 class FloorDiv(Node):
     def __init__(self, (left, right), lineno=None):
         self.left = left

Lib/compiler/pycodegen.py

@@ -1214,9 +1214,6 @@ def visitBitxor(self, node):
 
     # object constructors
 
-    def visitEllipsis(self, node):
-        self.emit('LOAD_CONST', Ellipsis)
-
     def visitTuple(self, node):
         self.set_lineno(node)
         for elt in node.nodes:

Lib/compiler/transformer.py

@@ -113,6 +113,7 @@ def __init__(self):
                                token.LBRACE: self.atom_lbrace,
                                token.NUMBER: self.atom_number,
                                token.STRING: self.atom_string,
+                               token.DOT: self.atom_ellipsis,
                                token.NAME: self.atom_name,
                                }
         self.encoding = None
@@ -747,6 +748,9 @@ def atom_string(self, nodelist):
             k += self.decode_literal(node[1])
         return Const(k, lineno=nodelist[0][2])
 
+    def atom_ellipsis(self, nodelist):
+        return Const(Ellipsis, lineno=nodelist[0][2])
+
     def atom_name(self, nodelist):
         return Name(nodelist[0][1], lineno=nodelist[0][2])
 
@@ -1276,11 +1280,9 @@ def com_subscriptlist(self, primary, nodelist, assigning):
                          lineno=extractLineNo(nodelist))
 
     def com_subscript(self, node):
-        # slice_item: expression | proper_slice | ellipsis
+        # slice_item: expression | proper_slice
         ch = node[1]
         t = ch[0]
-        if t == token.DOT and node[2][0] == token.DOT:
-            return Ellipsis()
         if t == token.COLON or len(node) > 2:
             return self.com_sliceobj(node)
         return self.com_node(ch)

Lib/test/output/test_grammar

@@ -7,6 +7,7 @@ test_grammar
 1.1.2.2 Long integers
 1.1.2.3 Floating point
 1.1.3 String literals
+1.1.4 Ellipsis literal
 1.2 Grammar
 single_input
 file_input

Lib/test/test_grammar.py

@@ -125,6 +125,12 @@
 '; verify(x == y)
 
 
+print '1.1.4 Ellipsis literal'
+
+x = ...
+verify(x == Ellipsis)
+
+
 print '1.2 Grammar'
 
 print 'single_input' # NEWLINE | simple_stmt | compound_stmt NEWLINE

Modules/parsermodule.c

@@ -2385,6 +2385,11 @@ validate_atom(node *tree)
             for (pos = 1; res && (pos < nch); ++pos)
                 res = validate_ntype(CHILD(tree, pos), STRING);
             break;
+	  case DOT:
+	    res = (nch == 3 &&
+	           validate_ntype(CHILD(tree, 1), DOT) &&
+		   validate_ntype(CHILD(tree, 2), DOT));
+	    break;
           default:
             res = 0;
             break;

Parser/Python.asdl

@@ -63,6 +63,7 @@ module Python version "$Revision$"
 			 expr? starargs, expr? kwargs)
 	     | Num(object n) -- a number as a PyObject.
 	     | Str(string s) -- need to specify raw, unicode, etc?
+	     | Ellipsis
 	     -- other literals? bools?
 
 	     -- the following expression can appear in assignment context
@@ -77,7 +78,7 @@ module Python version "$Revision$"
 
 	expr_context = Load | Store | Del | AugLoad | AugStore | Param
 
-	slice = Ellipsis | Slice(expr? lower, expr? upper, expr? step) 
+	slice = Slice(expr? lower, expr? upper, expr? step) 
 	      | ExtSlice(slice* dims) 
 	      | Index(expr value) 
 

Python/Python-ast.c

@@ -212,6 +212,7 @@ static PyTypeObject *Str_type;
 static char *Str_fields[]={
         "s",
 };
+static PyTypeObject *Ellipsis_type;
 static PyTypeObject *Attribute_type;
 static char *Attribute_fields[]={
         "value",
@@ -251,7 +252,6 @@ static PyTypeObject *AugStore_type;
 static PyTypeObject *Param_type;
 static PyTypeObject *slice_type;
 static PyObject* ast2obj_slice(void*);
-static PyTypeObject *Ellipsis_type;
 static PyTypeObject *Slice_type;
 static char *Slice_fields[]={
         "lower",
@@ -530,6 +530,8 @@ static int init_types(void)
         if (!Num_type) return 0;
         Str_type = make_type("Str", expr_type, Str_fields, 1);
         if (!Str_type) return 0;
+        Ellipsis_type = make_type("Ellipsis", expr_type, NULL, 0);
+        if (!Ellipsis_type) return 0;
         Attribute_type = make_type("Attribute", expr_type, Attribute_fields, 3);
         if (!Attribute_type) return 0;
         Subscript_type = make_type("Subscript", expr_type, Subscript_fields, 3);
@@ -570,8 +572,6 @@ static int init_types(void)
         slice_type = make_type("slice", AST_type, NULL, 0);
         if (!slice_type) return 0;
         if (!add_attributes(slice_type, NULL, 0)) return 0;
-        Ellipsis_type = make_type("Ellipsis", slice_type, NULL, 0);
-        if (!Ellipsis_type) return 0;
         Slice_type = make_type("Slice", slice_type, Slice_fields, 3);
         if (!Slice_type) return 0;
         ExtSlice_type = make_type("ExtSlice", slice_type, ExtSlice_fields, 1);
@@ -1578,6 +1578,21 @@ Str(string s, int lineno, int col_offset, PyArena *arena)
         return p;
 }
 
+expr_ty
+Ellipsis(int lineno, int col_offset, PyArena *arena)
+{
+        expr_ty p;
+        p = (expr_ty)PyArena_Malloc(arena, sizeof(*p));
+        if (!p) {
+                PyErr_NoMemory();
+                return NULL;
+        }
+        p->kind = Ellipsis_kind;
+        p->lineno = lineno;
+        p->col_offset = col_offset;
+        return p;
+}
+
 expr_ty
 Attribute(expr_ty value, identifier attr, expr_context_ty ctx, int lineno, int
           col_offset, PyArena *arena)
@@ -1720,19 +1735,6 @@ Tuple(asdl_seq * elts, expr_context_ty ctx, int lineno, int col_offset, PyArena
         return p;
 }
 
-slice_ty
-Ellipsis(PyArena *arena)
-{
-        slice_ty p;
-        p = (slice_ty)PyArena_Malloc(arena, sizeof(*p));
-        if (!p) {
-                PyErr_NoMemory();
-                return NULL;
-        }
-        p->kind = Ellipsis_kind;
-        return p;
-}
-
 slice_ty
 Slice(expr_ty lower, expr_ty upper, expr_ty step, PyArena *arena)
 {
@@ -2515,6 +2517,10 @@ ast2obj_expr(void* _o)
                         goto failed;
                 Py_DECREF(value);
                 break;
+        case Ellipsis_kind:
+                result = PyType_GenericNew(Ellipsis_type, NULL, NULL);
+                if (!result) goto failed;
+                break;
         case Attribute_kind:
                 result = PyType_GenericNew(Attribute_type, NULL, NULL);
                 if (!result) goto failed;
@@ -2648,10 +2654,6 @@ ast2obj_slice(void* _o)
         }
 
         switch (o->kind) {
-        case Ellipsis_kind:
-                result = PyType_GenericNew(Ellipsis_type, NULL, NULL);
-                if (!result) goto failed;
-                break;
         case Slice_kind:
                 result = PyType_GenericNew(Slice_type, NULL, NULL);
                 if (!result) goto failed;
@@ -3059,6 +3061,8 @@ init_ast(void)
         if (PyDict_SetItemString(d, "Call", (PyObject*)Call_type) < 0) return;
         if (PyDict_SetItemString(d, "Num", (PyObject*)Num_type) < 0) return;
         if (PyDict_SetItemString(d, "Str", (PyObject*)Str_type) < 0) return;
+        if (PyDict_SetItemString(d, "Ellipsis", (PyObject*)Ellipsis_type) < 0)
+            return;
         if (PyDict_SetItemString(d, "Attribute", (PyObject*)Attribute_type) <
             0) return;
         if (PyDict_SetItemString(d, "Subscript", (PyObject*)Subscript_type) <
@@ -3077,8 +3081,6 @@ init_ast(void)
             return;
         if (PyDict_SetItemString(d, "Param", (PyObject*)Param_type) < 0) return;
         if (PyDict_SetItemString(d, "slice", (PyObject*)slice_type) < 0) return;
-        if (PyDict_SetItemString(d, "Ellipsis", (PyObject*)Ellipsis_type) < 0)
-            return;
         if (PyDict_SetItemString(d, "Slice", (PyObject*)Slice_type) < 0) return;
         if (PyDict_SetItemString(d, "ExtSlice", (PyObject*)ExtSlice_type) < 0)
             return;

Python/ast.c

@@ -399,6 +399,9 @@ set_context(expr_ty e, expr_context_ty ctx, const node *n)
         case Str_kind:
             expr_name = "literal";
             break;
+	case Ellipsis_kind:
+	    expr_name = "Ellipsis";
+	    break;
         case Compare_kind:
             expr_name = "comparison";
             break;
@@ -1213,6 +1216,9 @@ ast_for_atom(struct compiling *c, const node *n)
 	PyArena_AddPyObject(c->c_arena, pynum);
 	return Num(pynum, LINENO(n), n->n_col_offset, c->c_arena);
     }
+    case DOT:
+    	/* Ellipsis */
+	return Ellipsis(LINENO(n), n->n_col_offset, c->c_arena);
     case LPAR: /* some parenthesized expressions */
 	ch = CHILD(n, 1);
 
@@ -1308,13 +1314,10 @@ ast_for_slice(struct compiling *c, const node *n)
     REQ(n, subscript);
 
     /*
-       subscript: '.' '.' '.' | test | [test] ':' [test] [sliceop]
+       subscript: test | [test] ':' [test] [sliceop]
        sliceop: ':' [test]
     */
     ch = CHILD(n, 0);
-    if (TYPE(ch) == DOT)
-	return Ellipsis(c->c_arena);
-
     if (NCH(n) == 1 && TYPE(ch) == test) {
         /* 'step' variable hold no significance in terms of being used over
            other vars */