Merge pull request #924 from mathics/SystemTimeZone

Add SystemTimeZone, adjust TimeZone..

CHANGES.rst

@@ -36,6 +36,7 @@ New features:
 - option ``--full-form`` (``-F``) on ``mathics`` to parsed ``FullForm`` of input expressions
 - ``Environment``
 - ``System`Byteordering`` ``System`Environemnt`` #859
+- ``SystemTimeZone`` and correct ``TimeZone`` #924
 
 Ehancements and Bug fixes:
 

mathics/builtin/__init__.py

@@ -5,10 +5,10 @@
 from mathics.builtin import (
     algebra, arithmetic, assignment, attributes, calculus, combinatorial, compilation,
     comparison, control, datentime, diffeqns, evaluation, exptrig, functional,
-    graphics, graphics3d, 
+    graphics, graphics3d,
     image, inout, integer, iohooks, linalg, lists, logic,
-    manipulate, quantities, numbertheory, numeric, options, patterns, 
-    plot, physchemdata, randomnumbers, recurrence, specialfunctions, scoping, 
+    manipulate, quantities, numbertheory, numeric, options, patterns,
+    plot, physchemdata, randomnumbers, recurrence, specialfunctions, scoping,
     strings, structure, system, tensors, xmlformat, optimization)
 
 from mathics.builtin.base import (
@@ -19,10 +19,10 @@
 modules = [
     algebra, arithmetic, assignment, attributes, calculus, combinatorial, compilation,
     comparison, control, datentime, diffeqns, evaluation, exptrig, functional,
-    graphics, graphics3d, 
-    image, inout, integer, iohooks, linalg, lists, logic, 
-    manipulate, quantities, numbertheory, numeric, options, patterns, 
-    plot, physchemdata, randomnumbers, recurrence, specialfunctions, scoping, 
+    graphics, graphics3d,
+    image, inout, integer, iohooks, linalg, lists, logic,
+    manipulate, quantities, numbertheory, numeric, options, patterns,
+    plot, physchemdata, randomnumbers, recurrence, specialfunctions, scoping,
     strings, structure, system, tensors, xmlformat, optimization]
 
 if ENABLE_FILES_MODULE:
@@ -120,6 +120,7 @@ def contribute(definitions):
     definitions.get_attributes('System`$Post').clear()
     definitions.get_attributes('System`$PrePrint').clear()
     definitions.get_attributes('System`$SyntaxHandler').clear()
+    definitions.get_attributes('System`$TimeZone').clear()
     definitions.get_attributes('System`$UseSansSerif').clear()
     from mathics.core.expression import ensure_context
     from mathics.core.parser import all_operator_names

mathics/builtin/datentime.py

@@ -538,6 +538,24 @@ def apply_spec(self, epochtime, evaluation):
         return from_python(total_seconds(tdelta))
 
 
+class SystemTimeZone(Predefined):
+    """
+    <dl>
+    <dt>'$SystemTimeZone'
+      <dd> gives the current time zone for the computer system on which Mathics is being run.
+    </dl>
+
+    >> $SystemTimeZone
+     = ...
+    """
+
+    name = '$SystemTimeZone'
+    value = Real(-time.timezone / 3600.)
+
+    def evaluate(self, evaluation):
+        return self.value
+
+
 class TimeZone(Predefined):
     """
     <dl>
@@ -549,10 +567,21 @@ class TimeZone(Predefined):
      = ...
     """
 
-    name = '$TimeZone'
+    name = "$TimeZone"
+    value = SystemTimeZone.value.copy()
 
-    def evaluate(self, evaluation):
-        return Real(-time.timezone / 3600.)
+    rules = {
+        "$TimeZone": str(value),
+    }
+
+    def apply(self, lhs, rhs, evaluation):
+        'lhs_ = rhs_'
+
+        self.assign(lhs, rhs, evaluation)
+        return rhs
+
+    def evaluate(self, evaluation) -> Real:
+        return self.value
 
 
 class TimeUsed(Builtin):

mathics/builtin/evaluation.py

@@ -76,7 +76,7 @@ class RecursionLimit(Predefined):
         '$RecursionLimit': str(value),
     }
 
-    def evaluate(self, evaluation):
+    def evaluate(self, evaluation) -> Integer:
         return Integer(self.value)
 
 
@@ -490,4 +490,3 @@ class Exit(Builtin):
 #        'Quit[n_Integer]': 'Exit[n]',
 #        'Quit': 'Exit',
 #    }
-

mathics/core/expression.py

@@ -7,7 +7,6 @@
 import mpmath
 import math
 import re
-from itertools import chain
 
 import typing
 from typing import Any