dutc

from sys import version_info
assert version_info.major == 3 and version_info.minor >= 3, \
  'requires PEP 362; Python 3.3 or later; python.org/dev/peps/pep-0362/'

from inspect import signature
class memoise(dict):
	def __init__(self, func):
		self.func, self.signature = func, signature(func)
	def __missing__(self, key):
		args, kwargs = key

dutc

#include <stdlib.h>
#include <stdio.h>

void f(int x[static 3]);

void f(int x[static 3]) {
	printf("%d + %d + %d = %d\n", x[0], x[1], x[2], x[0] + x[1] + x[2]);
}

int main(int argc, char* argv[]) {

dutc

from __future__ import division

# ref: en.wikipedia.org/wiki/Mersenne_twister
def mersenne(seed = 1, period=397, length=624):
    state, tm = [seed & 0xffffffff], lambda op, x: x ^ op(x)
    for i in xrange(1,length):
        state.append((0x6c078965 * (state[-1] ^ (state[-1] >> 30)) + i) & 0xffffffff)
    while True:    
        for i in xrange(length):
            y = (state[i] & 0x80000000) + (state[(i+1)%length] & 0x7fffffff)

dutc

themes

1. CPython for greater understanding of the Python programming language (but "reference implementations always overspecify") Reading source to solve problems
2. getting involved, contributing to the project

introduction

This workshop will cover the basics of the CPython runtime and interpreter. There is an enormous amount of material to cover, and I'll try to to rush through as much as I can.

dutc

diff -r 1e79ca2bc494 Doc/reference/compound_stmts.rst
--- a/Doc/reference/compound_stmts.rst	Wed Nov 20 11:53:31 2013 -0800
+++ b/Doc/reference/compound_stmts.rst	Wed Nov 20 20:23:32 2013 -0500
@@ -442,7 +442,7 @@
 .. productionlist::
    funcdef: [`decorators`] "def" `funcname` "(" [`parameter_list`] ")" ["->" `expression`] ":" `suite`
    decorators: `decorator`+
-   decorator: "@" `dotted_name` ["(" [`parameter_list` [","]] ")"] NEWLINE
+   decorator: "@" `expression` NEWLINE
    dotted_name: `identifier` ("." `identifier`)*

dutc

def test(filename, message):
	with open(filename, 'w') as f:
		f.write(message)

dutc

> I'm able to follow most of your instructions in the tutorial. However,
> there are things that are not yet obvious to me. If, for instance, I
> want to find the implementation of a specific built-in, where do I go?
> The `dis()` decompilation of `id()`, which I want to study, isn't
> instructive. Using `find ... -print0 | xargs -0 grep ...` also doesn't
> seem to get me anything useful. But I don't even see "builtins" file or
> a section of http://docs.python.org/3.3/c-api/index.html dealing with
> built-ins at all. Where should I be looking; how should I generalize
> this type of search for the future?

dutc

def f(x):
  print 'func_code is a restricted attribute', x.func_code

f(f) # this works

# overwrite __builtins__

old_builtins = __builtins__
new_builtins = type('module', (type(__builtins__),), {})('__builtins__')

dutc

#!/usr/bin/env python3

# using inspect
from inspect import currentframe, getframeinfo
class Foo:
    def __init__(self, quux):
        self.quux = quux

    def bar(self):
        return getframeinfo(currentframe()).function, self.quux

dutc

#!/usr/bin/env python3

class TaggedMethods(type):
    def __new__(cls, name, bases, body):
        tags = {}
        for name, attr in ((k,v) for k,v in body.items() if isinstance(v, Tag)):
            tags.setdefault(attr.tag, []).append(name)
            body[name] = attr.func
        body['methods_by_tag'] = property(lambda s: {k:[getattr(s,a) for a in v] for k,v in tags.items()})
        return type.__new__(cls, name, bases, body)