Add Contexts[string] form

mathics/__init__.py

@@ -51,7 +51,7 @@
 
     version_info[package] = package_version
 
-version_string = """Mathics {mathics}
+version_string = """Mathics3 {mathics}
 on {python}
 using SymPy {sympy}, mpmath {mpmath}, numpy {numpy}""".format(
     **version_info

mathics/builtin/scoping.py

@@ -12,6 +12,7 @@
 from mathics.core.evaluation import Evaluation
 from mathics.core.list import ListExpression
 from mathics.core.symbols import Symbol, fully_qualified_symbol_name
+from mathics.eval.scoping import eval_contexts, eval_contexts_with_string
 
 
 def get_scoping_vars(var_list, msg_symbol="", evaluation=None):
@@ -232,24 +233,38 @@ class Contexts(Builtin):
 
     <dl>
       <dt>'Contexts[]'
-      <dd>yields a list of all contexts.
+      <dd>returns a list of contexts.
+      <dt>'Contexts["string"]'
+      <dd>returns a list of contexts that match the string.
     </dl>
 
-    ## this assignment makes sure that a definition in Global` exists
-    ## >> x = 5;
-    ## X> Contexts[] // InputForm
+    'Contexts' allows the string patterns with the follwing metacharacters:
+    <ul>
+     <li> '*' zero or more characters
+     <li> '@' one or more characters, excluding uppercase letters
+    </ul>
+
+    Get a list of all contexts:
+    >> Contexts[]
+     = ...
+
+    Get a list of HTML contexts only:
+    >> Contexts["HTML*"]
+     = {HTML`, HTML`Parser`}
     """
 
-    summary_text = "list all the defined contexts"
+    summary_text = "list defined contexts"
 
-    def eval(self, evaluation: Evaluation):
+    def eval(self, evaluation: Evaluation) -> ListExpression:
         "Contexts[]"
 
-        contexts = set()
-        for name in evaluation.definitions.get_names():
-            contexts.add(String(name[: name.rindex("`") + 1]))
+        return eval_contexts(evaluation.definitions)
 
-        return ListExpression(*sorted(contexts))
+    def eval_with_string(self, string, evaluation: Evaluation) -> ListExpression:
+        "Contexts[string_]"
+        if not isinstance(string, String):
+            return ListExpression()
+        return eval_contexts_with_string(string.value, evaluation.definitions)
 
 
 class ContextPath_(Predefined):

mathics/builtin/system.py

@@ -10,6 +10,8 @@
 import subprocess
 import sys
 
+from pympler.asizeof import asizeof
+
 from mathics import version_string
 from mathics.core.atoms import Integer, Integer0, IntegerM1, Real, String
 from mathics.core.attributes import A_CONSTANT
@@ -383,41 +385,12 @@ class MemoryInUse(Builtin):
      = ...
     """
 
-    summary_text = "number of bytes of memory currently being used by Mathics"
+    summary_text = "number of bytes of memory currently being used by Mathics3"
 
-    def eval_0(self, evaluation) -> Integer:
+    def eval(self, evaluation: Evaluation) -> Integer:
         """MemoryInUse[]"""
-        # Partially borrowed from https://code.activestate.com/recipes/577504/
-        from itertools import chain
-        from sys import getsizeof
-
-        definitions = evaluation.definitions
-        seen = set()
-        try:
-            default_size = getsizeof(0)
-        except TypeError:
-            return IntegerM1
-
-        handlers = {
-            tuple: iter,
-            list: iter,
-            dict: (lambda d: chain.from_iterable(d.items())),
-            set: iter,
-            frozenset: iter,
-        }
-
-        def sizeof(obj):
-            if id(obj) in seen:
-                return 0
-            seen.add(id(obj))
-            s = getsizeof(obj, default_size)
-            for typ, handler in handlers.items():
-                if isinstance(obj, typ):
-                    s += sum(map(sizeof, handler(obj)))
-                    break
-            return s
-
-        return Integer(sizeof(definitions))
+        gc.collect()
+        return Integer(asizeof(evaluation.definitions))
 
 
 class Packages(Predefined):
@@ -794,7 +767,7 @@ class Version(Predefined):
     </dl>
 
     >> $Version
-     = Mathics ...
+     = Mathics3 ...
     """
 
     summary_text = "the current Mathics version"

mathics/core/definitions.py

@@ -280,7 +280,7 @@ def get_names(self):
             | self.get_user_names()
         )
 
-    def get_accessible_contexts(self):
+    def get_accessible_contexts(self) -> set:
         """Return the contexts reachable though $Context or $ContextPath."""
         accessible_ctxts = set(ctx for ctx in self.context_path)
         accessible_ctxts.add(self.current_context)
@@ -558,7 +558,8 @@ def mark_changed(self, definition: "Definition") -> None:
     def reset_user_definition(self, name) -> None:
         assert not isinstance(name, Symbol)
         fullname = self.lookup_name(name)
-        del self.user[fullname]
+        if fullname in self.user:
+            del self.user[fullname]
         self.clear_cache(fullname)
         # TODO fix changed
 

mathics/eval/scoping.py

@@ -1,4 +1,12 @@
+"""
+Evaluation module corresponding to builtin functions in mathics.builtins.scoping.
+"""
+import re
+
+from mathics.core.atoms import String
+from mathics.core.definitions import Definitions
 from mathics.core.evaluation import Evaluation
+from mathics.core.list import ListExpression
 from mathics.core.symbols import Symbol, fully_qualified_symbol_name
 
 
@@ -25,6 +33,35 @@ def dynamic_scoping(func, vars, evaluation: Evaluation):
     return result
 
 
+def eval_contexts(definitions: Definitions) -> ListExpression:
+    """
+    Corresponding eval routine (sans builtin class boilerplate) for Context[]
+    """
+    return ListExpression(*sorted(get_contexts(definitions)))
+
+
+def eval_contexts_with_string(string: str, definitions: Definitions) -> ListExpression:
+    """
+    Corresponding eval routine (sans builtin class boilerplate) for Context[string]
+    """
+    contexts = [context.value for context in get_contexts(definitions)]
+
+    short_pattern = (
+        string.replace("@", "[^A-Z]+").replace("*", ".*").replace("$", r"\$")
+    )
+    regex = re.compile("^" + short_pattern + "`$")
+
+    matched_contexts = [String(name) for name in contexts if regex.match(name)]
+    return ListExpression(*sorted(matched_contexts))
+
+
+def get_contexts(definitions) -> set:
+    contexts = set()
+    for name in definitions.get_names():
+        contexts.add(String(name[: name.rindex("`") + 1]))
+    return contexts
+
+
 def get_scoping_vars(var_list, msg_symbol="", evaluation=None):
     def message(tag, *args):
         if msg_symbol and evaluation:

pyproject.toml

@@ -22,7 +22,7 @@ dependencies = [
     "pillow >= 9.2",
     "pint",
     "python-dateutil",
-    # Pympler is used onlyfor ByteCount[]. It could be made optional.
+    # Pympler is used in ByteCount[] and MemoryInUse[].
     "Pympler",
     "requests",
     "scipy",