Merge pull request #1045 from mathics/SymbolNull

Add SymbolNull and try speeding up Workflows testing

Author: rocky

.github/workflows/basic.yml

@@ -29,4 +29,4 @@ jobs:
     - name: Test Mathics
       run: |
         pip install pytest pexpect
-        make check
+        make -j3 check

.travis.yml

@@ -2,7 +2,7 @@ dist: bionic
 language: python
 python:
   - 3.8
-  - pypy3.6-7.3.1
+#  - pypy3.6-7.3.1
 matrix:
   fast_finish: true
   include:
@@ -14,18 +14,16 @@ services:
   - xvfb
 before_install:
   - sudo apt-get update -qq && sudo apt-get install -qq liblapack-dev llvm-10 llvm-10-dev
-  - sudo apt-get install -qq gfortran
-  - sudo apt-get install -qq texlive-font-utils latexmk texlive-xetex lmodern inkscape
-  - sudo apt-get install -qq texlive-latex-extra texlive-fonts-recommended asymptote
+  - sudo apt-get install -qq gfortran texlive-font-utils latexmk texlive-xetex lmodern inkscape texlive-latex-extra texlive-fonts-recommended asymptote
   - LLVM_CONFIG=/usr/bin/llvm-config-10  CXXFLAGS=-fPIC python -m pip install llvmlite
-  - pip install ipywidgets ipykernel requests IPython==5.0.0 langid pycountry pyenchant lxml matplotlib
+  - pip install ipywidgets ipykernel requests IPython==5.0.0 langid pycountry pyenchant lxml matplotlib unittest2 pexpect
   - python travis.py
-  - pip install cython unittest2 pexpect
+  - pip install cython
 install:
   - sed -i "s/'sympy==[0-9]\.[0-9]\.[0-9]', //" setup.py
   - make develop
 script:
-  - make doc
+  - make -j3 doc
 notifications:
     email: false
     slack: mathics:VIjdkcZPlA79sOtVOtyjdOcT

mathics/core/expression.py

@@ -1778,7 +1778,7 @@ def to_python(self, *args, **kwargs):
             return True
         if self == SymbolFalse:
             return False
-        if self.name == 'System`Null':
+        if self == SymbolNull:
             return None
         n_evaluation = kwargs.get('n_evaluation')
         if n_evaluation is not None:
@@ -1846,8 +1846,10 @@ def user_hash(self, update) -> None:
     def __getnewargs__(self):
         return (self.name, self.sympy_dummy)
 
+# Some common Symbols
 SymbolTrue = Symbol("True")
 SymbolFalse = Symbol("False")
+SymbolNull = Symbol("Null")
 
 class Number(Atom):
     def __str__(self) -> str:

mathics/core/numbers.py

@@ -51,10 +51,10 @@ def _get_float_inf(value, evaluation) -> typing.Optional[float]:
 
 
 def get_precision(value, evaluation) -> typing.Optional[int]:
-    from mathics.core.expression import Symbol, MachineReal
     if value.get_name() == 'System`MachinePrecision':
         return None
     else:
+        from mathics.core.expression import Symbol, MachineReal
         dmin = _get_float_inf(Symbol('$MinPrecision'), evaluation)
         dmax = _get_float_inf(Symbol('$MaxPrecision'), evaluation)
         d = value.round_to_float(evaluation)