Mastering Python Second Edition Release Code

CH_02_interactive_python/README.rst

@@ -0,0 +1,3 @@
+Chapter 2, Interactive Python Shells
+##############################################################################
+

CH_02_interactive_python/T_00_the_python_interpreter.rst

@@ -0,0 +1,2 @@
+>>> 'Hello world!'
+'Hello world!'

CH_02_interactive_python/T_01_modifying_the_interpreter.rst

@@ -0,0 +1,27 @@
+# Adding default imports
+
+>>> from pprint import pprint as pp
+>>> from pprint import pformat as pf
+
+>>> pp(dict(spam=0xA, eggs=0xB))
+{'eggs': 11, 'spam': 10}
+>>> pf(dict(spam=0xA, eggs=0xB))
+"{'eggs': 11, 'spam': 10}"
+
+
+# Modifying prompt
+
+>>> if True:
+...     print('Hello!')
+Hello!
+
+>>> import sys
+
+>>> sys.ps1 = '> '
+>>> sys.ps2 = '. '
+
+# With modified prompt
+
+> if True:
+.     print('Hello!')
+Hello!

CH_02_interactive_python/T_02_modifying_autocompletion.py

@@ -0,0 +1,76 @@
+import __main__
+import re
+import atexit
+import readline
+import rlcompleter
+
+
+class Completer(rlcompleter.Completer):
+
+    ITEM_RE = re.compile(r'(?P<expression>.+?)\[(?P<key>[^\[]*)')
+
+    def complete(self, text, state):
+        # Init namespace. From `rlcompleter.Completer.complete`
+        if self.use_main_ns:
+            self.namespace = __main__.__dict__
+
+        # If we find a [, try and return the keys
+        if '[' in text:
+            # At state 0 we need to prefetch the matches, after
+            # that we use the cached results
+            if state == 0:
+                self.matches = list(self.item_matches(text))
+
+            # Try and return the match if it exists
+            try:
+                return self.matches[state]
+            except IndexError:
+                pass
+        else:
+            # Fallback to the normal completion
+            return super().complete(text, state)
+
+    def item_matches(self, text):
+        # Look for the pattern expression[key
+        match = self.ITEM_RE.match(text)
+        if match:
+            search_key = match.group('key').lstrip()
+            expression = match.group('expression')
+
+            # Strip quotes from the key
+            if search_key and search_key[0] in {"'", '"'}:
+                search_key = search_key.strip(search_key[0])
+
+            # Fetch the object from the namespace
+            object_ = eval(expression, self.namespace)
+
+            # Duck typing, check if we have a `keys()` attribute
+            if hasattr(object_, 'keys'):
+                # Fetch the keys by executing the `keys()` method
+                # Can you guess where the bug is?
+                keys = object_.keys()
+                for i, key in enumerate(keys):
+                    # Limit to 25 items for safety, could be
+                    # infinite
+                    if i >= 25:
+                        break
+
+                    # Only return matching results
+                    if key.startswith(search_key):
+                        yield f'{expression}[{key!r}]'
+
+
+# By default readline doesn't call the autocompleter for [ because
+# it's considered a delimiter. With a little bit of work we can
+# fix this however :)
+delims = readline.get_completer_delims()
+# Remove [, ' and " from the delimiters
+delims = delims.replace('[', '').replace('"', '').replace("'", '')
+# Set the delimiters
+readline.set_completer_delims(delims)
+
+# Create and set the completer
+completer = Completer()
+readline.set_completer(completer.complete)
+# Add a cleanup call on Python exit
+atexit.register(lambda: readline.set_completer(None))

CH_02_interactive_python/T_02_modifying_autocompletion.rst

@@ -0,0 +1,15 @@
+>>> sandwich = dict(spam=2, eggs=1, sausage=1)
+>>> sandwich.<TAB>  # doctest: +SKIP
+sandwich.clear(       sandwich.fromkeys(    sandwich.items(       sandwich.pop(
+sandwich.setdefault(  sandwich.values(      sandwich.copy(        sandwich.get(
+sandwich.keys(        sandwich.popitem(     sandwich.update(
+>>> sandwich[  # doctest: +SKIP
+
+
+>>> sandwich = dict(spam=2, eggs=1, sausage=1)
+>>> sandwich['<TAB>  # doctest: +SKIP
+sandwich['eggs']     sandwich['sausage']  sandwich['spam']
+
+>>> import T_02_modifying_autocompletion
+
+>>> autocompletion = T_02_modifying_autocompletion

CH_02_interactive_python/T_03_bpython_rewind.rst

@@ -0,0 +1,25 @@
+Note: missing_ok was added in Python 3.8
+
+>>> import pathlib
+
+>>> pathlib.Path('bpython.txt').unlink(missing_ok=True)
+
+>>> with open('bpython.txt', 'a') as fh:
+...     fh.write('x')
+...
+1
+>>> with open('bpython.txt') as fh:
+...     print(fh.read())
+...
+x
+>>> sandwich = dict(spam=2, eggs=1, sausage=1)
+
+>>> with open('bpython.txt', 'a') as fh:
+...     fh.write('x')
+...
+1
+>>> with open('bpython.txt') as fh:
+...     print(fh.read())
+...
+xx
+>>>

CH_02_interactive_python/bpython_reload.py

@@ -0,0 +1,4 @@
+with open('reload.txt', 'a+') as fh:
+    fh.write('x')
+    fh.seek(0)
+    print(fh.read())

CH_02_interactive_python/conftest.py

@@ -0,0 +1,7 @@
+import sys
+import pathlib
+
+# Little hack to add the current directory to sys.path so we can
+# find the imports
+path = pathlib.Path(__file__).parent
+sys.path.append(str(path.resolve()))

CH_02_interactive_python/reload.txt

@@ -0,0 +1 @@
+xxxxx

CH_02_interactive_python/session_filename.ipy

@@ -0,0 +1,3 @@
+# coding: utf-8
+
+sandwich = dict(spam=2, eggs=1, sausage=1)