https://www.dabeaz.com/courses.html

https://github.com/dabeaz-course/practical-python/blob/master/Notes/Contents.md

https://superfastpython.com/about/

https://mathspp.com/blog/building-a-python-compiler-and-interpreter

https://blog.codingconfessions.com/p/cpython-vm-internals

Package & Module

1. Explicit relative imports more better

   spam/
         __init__.py
         foo.py
         bar.py
   # explicit relative imports （Better)
   from . import foo      # Loads ./foo.py
   from .. import foo     # Loads ../foo.py
   from ..grok import foo # Loads ../grok/foo.py
   
   # use an absolute module import
   from spam import foo # verbose, fragile
   
   # implicit relative imports
   import foo # It works in Pyhon2, but not Python3
   

2. __init__.py

   I think they should mainly be used to stitch together multiple source files into a "unified" top-level import (if desired)

   # case 1
   spam/
         __init__.py
         foo.py
         bar.py
   
   __init__.py
   from .foo import Foo
   from .bar import Bar
   
   # case 2
   # Each submodule should define __all__
   __init__.py
   from .foo import *
   from .bar import *
   __all__ = (foo.__all__ + bar.__all__)
   

3. Export decorator

   # spam/__init__.py
   __all__ = []
   def export(defn):
      globals()[defn.__name__] = defn
      __all__.append(defn.__name__)
   	 return defn
   
   from . import foo
   from . import bar
   
   # spam/foo.py
   from . import export
   @export
   def blah():
   	...
   
   @export
   class Foo(object):
   	...
   

4. __path__ 定义了package的root目录，用来寻找submodule

   # __init__.py
   # 让package去其他目录寻找submodule
   __path__.append('/some/additional/path')
   

5. sys.path、egg、zip、site.py、sys.prefix、sys.exec_prefix

   # Python standard libraries usually located at
   sys.prefix + '/lib/python3X.zip'
   sys.prefix + '/lib/python3.X'
   sys.prefix + '/lib/python3.X/plat-sysname' 
   sys.exec_prefix + '/lib/python3.X/lib-dynload'
   
   # PYTHONHOME environment overrides location
   # PYTHONPATH environment variable
   

Default arguments must appear last in definition