Rename element order values with _ELT_ORDER suffix (#1508)

My beef with the suffix `_SORT_KEY` is that it is vague (what is sorted,
and why?). Also, we use the `_SORT_KEY` suffix for the pattern selection
precedence this has nothing to do with element ordering.

The `_ELT_ORDER` suffix aims to make things clearer and less ambiguous.

Author: rocky

mathics/builtin/compilation.py

@@ -25,7 +25,7 @@
 from mathics.core.element import ImmutableValueMixin
 from mathics.core.evaluation import Evaluation
 from mathics.core.expression import Expression
-from mathics.core.keycomparable import LITERAL_EXPRESSION_SORT_KEY
+from mathics.core.keycomparable import LITERAL_EXPRESSION_ELT_ORDER
 from mathics.core.symbols import Atom, Symbol, SymbolFalse, SymbolTrue
 from mathics.core.systemsymbols import SymbolCompiledFunction
 
@@ -146,7 +146,7 @@ def element_order(self) -> tuple:
         lexicographically.
 
         """
-        return (LITERAL_EXPRESSION_SORT_KEY, hex(id(self)))
+        return (LITERAL_EXPRESSION_ELT_ORDER, hex(id(self)))
 
     @property
     def pattern_precedence(self) -> tuple:

mathics/builtin/image/base.py

@@ -12,7 +12,7 @@
 from mathics.core.builtin import AtomBuiltin, String
 from mathics.core.evaluation import Evaluation
 from mathics.core.expression import Expression
-from mathics.core.keycomparable import IMAGE_EXPRESSION_SORT_KEY
+from mathics.core.keycomparable import IMAGE_EXPRESSION_ELT_ORDER
 from mathics.core.list import ListExpression
 from mathics.core.systemsymbols import SymbolImage, SymbolRule
 from mathics.eval.image import image_pixels, pixels_as_float, pixels_as_ubyte
@@ -122,7 +122,7 @@ def element_order(self) -> tuple:
         # and adding two extra fields: the length in the 5th position,
         # and a hash in the 6th place.
         return (
-            IMAGE_EXPRESSION_SORT_KEY,
+            IMAGE_EXPRESSION_ELT_ORDER,
             SymbolImage,
             len(self.pixels),
             tuple(),

mathics/core/atoms.py

@@ -12,9 +12,9 @@
 
 from mathics.core.element import BoxElementMixin, ImmutableValueMixin
 from mathics.core.keycomparable import (
-    BASIC_ATOM_BYTEARRAY_SORT_KEY,
-    BASIC_ATOM_NUMBER_SORT_KEY,
-    BASIC_ATOM_STRING_SORT_KEY,
+    BASIC_ATOM_BYTEARRAY_ELT_ORDER,
+    BASIC_ATOM_NUMBER_ELT_ORDER,
+    BASIC_ATOM_STRING_ELT_ORDER,
 )
 from mathics.core.number import (
     FP_MANTISA_BINARY_DIGITS,
@@ -91,7 +91,7 @@ def element_order(self) -> tuple:
         of an expression. The tuple is ultimately compared lexicographically.
         """
         return (
-            BASIC_ATOM_NUMBER_SORT_KEY,
+            BASIC_ATOM_NUMBER_ELT_ORDER,
             self.value,
             0,
             1,
@@ -722,7 +722,7 @@ def element_order(self) -> tuple:
         of an expression. The tuple is ultimately compared lexicographically.
         """
         return (
-            BASIC_ATOM_BYTEARRAY_SORT_KEY,
+            BASIC_ATOM_BYTEARRAY_ELT_ORDER,
             self.value,
             "utf-8",
             0,
@@ -887,7 +887,7 @@ def element_order(self) -> tuple:
         of an expression. The tuple is ultimately compared lexicographically.
         """
         return (
-            BASIC_ATOM_NUMBER_SORT_KEY,
+            BASIC_ATOM_NUMBER_ELT_ORDER,
             self.real.element_order[1],
             self.imag.element_order[1],
             1,
@@ -1049,7 +1049,7 @@ def element_order(self) -> tuple:
         """
         # HACK: otherwise "Bus error" when comparing 1==1.
         return (
-            BASIC_ATOM_NUMBER_SORT_KEY,
+            BASIC_ATOM_NUMBER_ELT_ORDER,
             sympy.Float(self.value),
             0,
             1,
@@ -1140,7 +1140,7 @@ def element_order(self) -> tuple:
         of an expression. The tuple is ultimately compared lexicographically.
         """
         return (
-            BASIC_ATOM_STRING_SORT_KEY,
+            BASIC_ATOM_STRING_ELT_ORDER,
             self.value,
             0,
             1,

mathics/core/expression.py

@@ -40,10 +40,10 @@
 from mathics.core.evaluation import Evaluation
 from mathics.core.interrupt import ReturnInterrupt
 from mathics.core.keycomparable import (
-    BASIC_EXPRESSION_SORT_KEY,
-    BASIC_NUMERIC_EXPRESSION_SORT_KEY,
-    GENERAL_EXPRESSION_SORT_KEY,
-    GENERAL_NUMERIC_EXPRESSION_SORT_KEY,
+    BASIC_EXPRESSION_ELT_ORDER,
+    BASIC_NUMERIC_EXPRESSION_ELT_ORDER,
+    GENERAL_EXPRESSION_ELT_ORDER,
+    GENERAL_NUMERIC_EXPRESSION_ELT_ORDER,
     Monomial,
 )
 from mathics.core.structure import LinkedStructure
@@ -897,7 +897,7 @@ def element_order(self) -> tuple:
         of an expression. The tuple is ultimately compared lexicographically.
         """
         """
-        General sort key structure:
+        General element order key structure:
         0: 1/2:        Numeric / General Expression
         1: 2/3         Special arithmetic (Times / Power) / General Expression
         2: Element:        Head
@@ -932,9 +932,9 @@ def element_order(self) -> tuple:
         if exps:
             return (
                 (
-                    BASIC_NUMERIC_EXPRESSION_SORT_KEY
+                    BASIC_NUMERIC_EXPRESSION_ELT_ORDER
                     if self.is_numeric()
-                    else BASIC_EXPRESSION_SORT_KEY
+                    else BASIC_EXPRESSION_ELT_ORDER
                 ),
                 Monomial(exps),
                 1,
@@ -945,9 +945,9 @@ def element_order(self) -> tuple:
         else:
             return (
                 (
-                    GENERAL_NUMERIC_EXPRESSION_SORT_KEY
+                    GENERAL_NUMERIC_EXPRESSION_ELT_ORDER
                     if self.is_numeric()
-                    else GENERAL_EXPRESSION_SORT_KEY
+                    else GENERAL_EXPRESSION_ELT_ORDER
                 ),
                 head,
                 len(self._elements),

mathics/core/keycomparable.py

@@ -272,16 +272,17 @@ def __ne__(self, other) -> bool:
 )  # Used as the last element in the third field.
 
 
-###  SORT_KEYS prefix for expression_order
+###  _ELT_ORDER suffixes are used in element ordering and
+###  Expression.element_order().
 
-BASIC_ATOM_NUMBER_SORT_KEY = 0x00
-BASIC_ATOM_STRING_SORT_KEY = 0x01
-BASIC_ATOM_BYTEARRAY_SORT_KEY = 0x02
-LITERAL_EXPRESSION_SORT_KEY = 0x03
+BASIC_ATOM_NUMBER_ELT_ORDER = 0x00
+BASIC_ATOM_STRING_ELT_ORDER = 0x01
+BASIC_ATOM_BYTEARRAY_ELT_ORDER = 0x02
+LITERAL_EXPRESSION_ELT_ORDER = 0x03
 
-BASIC_NUMERIC_EXPRESSION_SORT_KEY = 0x12
-GENERAL_NUMERIC_EXPRESSION_SORT_KEY = 0x13
-IMAGE_EXPRESSION_SORT_KEY = 0x13
+BASIC_NUMERIC_EXPRESSION_ELT_ORDER = 0x12
+GENERAL_NUMERIC_EXPRESSION_ELT_ORDER = 0x13
+IMAGE_EXPRESSION_ELT_ORDER = 0x13
 
-BASIC_EXPRESSION_SORT_KEY = 0x22
-GENERAL_EXPRESSION_SORT_KEY = 0x23
+BASIC_EXPRESSION_ELT_ORDER = 0x22
+GENERAL_EXPRESSION_ELT_ORDER = 0x23

mathics/core/symbols.py

@@ -16,8 +16,8 @@
 
 from mathics.core.keycomparable import (
     BASIC_ATOM_PATTERN_SORT_KEY,
-    BASIC_EXPRESSION_SORT_KEY,
-    BASIC_NUMERIC_EXPRESSION_SORT_KEY,
+    BASIC_EXPRESSION_ELT_ORDER,
+    BASIC_NUMERIC_EXPRESSION_ELT_ORDER,
     Monomial,
 )
 from mathics.eval.tracing import trace_evaluate
@@ -558,9 +558,9 @@ def element_order(self) -> tuple:
         """
         return (
             (
-                BASIC_NUMERIC_EXPRESSION_SORT_KEY
+                BASIC_NUMERIC_EXPRESSION_ELT_ORDER
                 if self.is_numeric()
-                else BASIC_EXPRESSION_SORT_KEY
+                else BASIC_EXPRESSION_ELT_ORDER
             ),
             Monomial({self.name: 1}),
             0,