Fix remaining mypy errors in mathics.core (#1147)

This fixes the remaining mypy errors in `mathics.core`, with the
exception of `mathics.core.expression` which needs a bit more work.

mathics/core/assignment.py

@@ -592,7 +592,8 @@ def eval_assign_numericq(self, lhs, rhs, evaluation: Evaluation, tags, upset):
     if isinstance(target, Symbol):
         name = target.get_name()
         definition = evaluation.definitions.get_definition(name)
-        definition.is_numeric = rhs is SymbolTrue
+        if definition is not None:
+            definition.is_numeric = rhs is SymbolTrue
         return True
     else:
         evaluation.message("NumericQ", "set", lhs, rhs)

mathics/core/atoms.py

@@ -6,7 +6,7 @@
 import re
 from typing import Any, Dict, Generic, Optional, Tuple, TypeVar, Union
 
-import mpmath
+import mpmath  # type: ignore[import-untyped]
 import sympy
 
 from mathics.core.element import BoxElementMixin, ImmutableValueMixin

mathics/core/builtin.py

@@ -13,9 +13,20 @@
 from abc import ABC
 from functools import total_ordering
 from itertools import chain
-from typing import Any, Callable, Dict, Iterable, List, Optional, Tuple, Union, cast
+from typing import (
+    Any,
+    Callable,
+    Dict,
+    Iterable,
+    List,
+    Optional,
+    Sequence,
+    Tuple,
+    Union,
+    cast,
+)
 
-import mpmath
+import mpmath  # type: ignore[import-untyped]
 import pkg_resources
 import sympy
 
@@ -84,7 +95,7 @@
 try:
     import ujson
 except ImportError:
-    import json as ujson
+    import json as ujson  # type: ignore[no-redef]
 
 ROOT_DIR = pkg_resources.resource_filename("mathics", "")
 
@@ -551,6 +562,12 @@ def get_sympy_names(self) -> List[str]:
             return [self.sympy_name]
         return []
 
+    def to_sympy(self, expr=None, **kwargs):
+        raise NotImplementedError
+
+    def from_sympy(self, elements: Tuple[BaseElement, ...]) -> Expression:
+        raise NotImplementedError
+
 
 # This has to come before MPMathFunction
 class SympyFunction(SympyObject):
@@ -651,6 +668,8 @@ def eval(self, z, evaluation: Evaluation):
 
         if not all(isinstance(arg, Number) for arg in args):
             return
+        # mypy isn't yet smart enough to recognise that we can only reach this point if all args are Numbers
+        args = cast(Sequence[Number], args)
 
         mpmath_function = self.get_mpmath_function(tuple(args))
         if mpmath_function is None:
@@ -663,7 +682,9 @@ def eval(self, z, evaluation: Evaluation):
             d = dps(prec)
             args = tuple([arg.round(d) for arg in args])
 
-        return eval_mpmath_function(mpmath_function, *args, prec=prec)
+        return eval_mpmath_function(
+            mpmath_function, *cast(Sequence[Number], args), prec=prec
+        )
 
 
 class MPMathMultiFunction(MPMathFunction):
@@ -1235,7 +1256,7 @@ def get_match_candidates(
     ) -> Tuple[BaseElement]:
         return elements
 
-    def get_match_count(self, vars_dict: dict = {}):
+    def get_match_count(self, vars_dict: Optional[dict] = None):
         return (1, 1)
 
     def get_sort_key(self, pattern_sort=False) -> tuple:

mathics/core/convert/expression.py

@@ -83,16 +83,16 @@ def to_mathics_list(
     return list_expression
 
 
-def to_numeric_args(mathics_args: Type[BaseElement], evaluation) -> list:
+def to_numeric_args(mathics_args: BaseElement, evaluation) -> tuple:
     """
     Convert Mathics arguments, such as the arguments in an evaluation
     method a Python list that is suitable for feeding as arguments
     into SymPy, NumPy, or mpmath.
 
     We make use of fast conversions for literals.
     """
-    return (
-        tuple(mathics_args.value)
+    return tuple(
+        mathics_args.value  # type: ignore[attr-defined]
         if mathics_args.is_literal
         else numerify(mathics_args, evaluation).get_sequence()
     )

mathics/core/convert/function.py

@@ -83,7 +83,9 @@ def _pythonized_mathics_expr(*x):
 
 
 def expression_to_callable_and_args(
-    expr: Expression, vars: list = None, evaluation: Optional[Evaluation] = None
+    expr: Expression,
+    vars: Optional[list] = None,
+    evaluation: Optional[Evaluation] = None,
 ) -> Tuple[Optional[Callable], Optional[list]]:
     """
     Return a tuple of Python callable and a list of CompileArgs.

mathics/core/convert/mpmath.py

@@ -3,7 +3,7 @@
 from functools import lru_cache
 from typing import Optional, Union
 
-import mpmath
+import mpmath  # type: ignore[import-untyped]
 import sympy
 
 from mathics.core.atoms import Complex, MachineReal, MachineReal0, PrecisionReal

mathics/core/convert/op.py

@@ -10,7 +10,7 @@
 try:
     import ujson
 except ImportError:
-    import json as ujson
+    import json as ujson  # type: ignore[no-redef]
 
 ROOT_DIR = pkg_resources.resource_filename("mathics", "")
 

mathics/core/convert/regex.py

@@ -96,7 +96,7 @@ def to_regex_internal(
     (None, "") is returned if there is an error of some sort.
     """
 
-    def recurse(x: Expression, quantifiers=q) -> Tuple[Optional[str], str]:
+    def recurse(x: Expression, quantifiers=q) -> Optional[str]:
         """
         Shortened way to call to_regexp_internal -
         only the expr and quantifiers change here.

mathics/core/convert/sympy.py

@@ -4,7 +4,7 @@
 Converts expressions from SymPy to Mathics expressions.
 Conversion to SymPy is handled directly in BaseElement descendants.
 """
-from typing import Optional, Type, Union
+from typing import TYPE_CHECKING, Dict, List, Optional, Sequence, Tuple, Union, cast
 
 import sympy
 from sympy import Symbol as Sympy_Symbol, false as SympyFalse, true as SympyTrue
@@ -66,6 +66,9 @@
     SymbolUnequal,
 )
 
+if TYPE_CHECKING:
+    from mathics.core.builtin import SympyObject
+
 BasicSympy = sympy.Expr
 
 
@@ -74,8 +77,8 @@
 SymbolRootSum = Symbol("RootSum")
 
 
-mathics_to_sympy = {}  # here we have: name -> sympy object
-sympy_to_mathics = {}
+mathics_to_sympy: Dict[str, "SympyObject"] = {}  # here we have: name -> sympy object
+sympy_to_mathics: Dict[str, "SympyObject"] = {}
 
 
 sympy_singleton_to_mathics = {
@@ -104,14 +107,14 @@
 }
 
 
-def is_Cn_expr(name) -> bool:
+def is_Cn_expr(name: str) -> bool:
     """Check if name is of the form {prefix}Cnnn"""
     if name.startswith(sympy_symbol_prefix) or name.startswith(sympy_slot_prefix):
         return False
     if not name.startswith("C"):
         return False
     number = name[1:]
-    return number and number.isdigit()
+    return number != "" and number.isdigit()
 
 
 def to_sympy_matrix(data, **kwargs) -> Optional[sympy.MutableDenseMatrix]:
@@ -131,6 +134,7 @@ class SympyExpression(BasicSympy):
 
     is_Function = True
     nargs = None
+    expr: Expression
 
     def __new__(cls, *exprs):
         # sympy simplify may also recreate the object if simplification occurred
@@ -167,7 +171,11 @@ def __new__(cls, *args):
 
     def has_any_symbols(self, *syms) -> bool:
         """Check if any of the symbols in syms appears in the expression."""
-        result = any(arg.has_any_symbols(*syms) for arg in self.args)
+        result = any(
+            arg.has_any_symbols(*syms)
+            for arg in self.args
+            if isinstance(arg, SympyExpression)
+        )
         return result
 
     def _eval_subs(self, old, new):
@@ -185,10 +193,14 @@ def _eval_rewrite(self, rule, args, **hints):
         return self
 
     @property
-    def is_commutative(self) -> bool:
+    def is_commutative(self) -> Optional[bool]:
         """Check if the arguments are commutative."""
         return all(getattr(t, "is_commutative", False) for t in self.args)
 
+    @is_commutative.setter
+    def is_commutative(self, value: bool) -> None:
+        return
+
     def __str__(self) -> str:
         return f"{super().__str__()}[{self.expr}])"
 
@@ -257,7 +269,7 @@ def symbol_to_sympy(symbol: Symbol, **kwargs) -> Sympy_Symbol:
     return builtin.to_sympy(symbol, **kwargs)
 
 
-def to_numeric_sympy_args(mathics_args: Type[BaseElement], evaluation) -> list:
+def to_numeric_sympy_args(mathics_args: BaseElement, evaluation) -> list:
     """
     Convert Mathics arguments, such as the arguments in an evaluation
     method a Python list that is sutiable for feeding as arguments
@@ -268,6 +280,7 @@ def to_numeric_sympy_args(mathics_args: Type[BaseElement], evaluation) -> list:
     from mathics.eval.numerify import numerify
 
     if mathics_args.is_literal:
+        assert hasattr(mathics_args, "value")
         sympy_args = [mathics_args.value]
     else:
         args = numerify(mathics_args, evaluation).get_sequence()
@@ -352,16 +365,16 @@ def old_from_sympy(expr) -> BaseElement:
         if expr.is_Symbol:
             name = str(expr)
             if isinstance(expr, sympy.Dummy):
-                name = name + (f"__Dummy_{expr.dummy_index}")
+                name = name + (f"__Dummy_{expr.dummy_index}")  # type: ignore[attr-defined]
                 # Probably, this should be the value attribute
                 return Symbol(name, sympy_dummy=expr)
             if is_Cn_expr(name):
                 return Expression(SymbolC, Integer(int(name[1:])))
             if name.startswith(sympy_symbol_prefix):
                 name = name[len(sympy_symbol_prefix) :]
             if name.startswith(sympy_slot_prefix):
-                index = name[len(sympy_slot_prefix) :]
-                return Expression(SymbolSlot, Integer(int(index)))
+                index = int(name[len(sympy_slot_prefix) :])
+                return Expression(SymbolSlot, Integer(index))
         elif expr.is_NumberSymbol:
             name = str(expr)
         if name is not None:
@@ -427,25 +440,26 @@ def old_from_sympy(expr) -> BaseElement:
         return expr.expr
 
     if isinstance(expr, sympy.Piecewise):
-        args = expr.args
         return Expression(
             SymbolPiecewise,
             ListExpression(
                 *[
                     to_mathics_list(from_sympy(case), from_sympy(cond))
-                    for case, cond in args
+                    for case, cond in cast(
+                        Sequence[Tuple[sympy.Basic, sympy.Basic]], expr.args
+                    )
                 ]
             ),
         )
 
     if isinstance(expr, SympyPrime):
         return Expression(SymbolPrime, from_sympy(expr.args[0]))
     if isinstance(expr, sympy.RootSum):
-        return Expression(SymbolRootSum, from_sympy(expr.poly), from_sympy(expr.fun))
+        return Expression(SymbolRootSum, from_sympy(expr.poly), from_sympy(expr.fun))  # type: ignore[attr-defined]
     if isinstance(expr, sympy.PurePoly):
         coeffs = expr.coeffs()
         monoms = expr.monoms()
-        result = []
+        result: List[BaseElement] = []
         for coeff, monom in zip(coeffs, monoms):
             factors = []
             if coeff != 1:
@@ -500,12 +514,14 @@ def old_from_sympy(expr) -> BaseElement:
                 else:
                     margs.append(from_sympy(arg))
             builtin = sympy_to_mathics.get(name)
-            return builtin.from_sympy(margs)
+            assert builtin is not None
+            return builtin.from_sympy(tuple(margs))
 
         elif isinstance(expr, sympy.sign):
             name = "Sign"
         else:
             name = expr.func.__name__
+            assert name is not None
             if is_Cn_expr(name):
                 return Expression(
                     Expression(Symbol("C"), Integer(int(name[1:]))),
@@ -516,7 +532,7 @@ def old_from_sympy(expr) -> BaseElement:
         args = [from_sympy(arg) for arg in expr.args]
         builtin = sympy_to_mathics.get(name)
         if builtin is not None:
-            return builtin.from_sympy(args)
+            return builtin.from_sympy(tuple(args))
         return Expression(Symbol(name), *args)
 
     if isinstance(expr, sympy.Tuple):