syntax_sugar travis_status PyPI
This lib adds some anti-Pythonic "syntactic sugar" to Python.
NOTE: This is merely an experimental prototype to show some potential of operator overloading in Python. Only tested under Python 3.6.0. Anything may evolve without announcement in advance.
Inspired by https://github.com/matz/streem.
Also, you can watch the last part of this Matz's talk to understand the intuition behind this project.
pip install syntax_sugar
To test out this lib, you can simply do.
from syntax_sugar import *
For serious use, you can explicitly import each component as explained below ... if you dare to use this lib.
from syntax_sugar import pipe, END from functools import partial pipe(10) | range | partial(map, lambda x: x**2) | list | print | END # put 10 into the pipe and just let data flow. # output: [0, 1, 4, 9, 16, 25, 36, 49, 64, 81] # remember to call END at the end # NOTE: everything in the middle of the pipe is just normal Python functions pipe(10) | range | (map, lambda x: x**2) | list | print | END # Tuples are shortcuts for partial functions from syntax_sugar import each x = pipe(10) | range | each(lambda x: x ** 2) | END # We can also save the result in a variable. # `each` is an eager evaluated version of the partial function of `map`, which returns a list instead of a map object. (Equivalent to `map` in Python 2) pipe(10) | range | each(str) | ''.join > 'test.txt' # wanna write to a file? Why not! # write "0123456789" to test.txt # We don't need to put END here.
We can connect multiple pipes to create a longer pipe
from syntax_sugar import pipe, each, END from functools import reduce p1 = pipe(10) | range | each(lambda x: x/2) # head pipe can have input value p2 = pipe() | (reduce, lambda acc, x: (acc + x)/2) p3 = pipe() | int | range | sum # middle pipes can have no input value p1 | p2 | p3 | END # returns 6 p = p1 | p2 | p3 p() # You can invoke the pipe by calling it as a function # you can also put a different value in the pipe p(20) # returns 36
By default, pipe works with threads.
You can have a function running in a seperate thread with pipe. Just put it in a [] or more explicitly t[]. Threads and processes are also available.
from syntax_sugar import (thread_syntax as t, process_syntax as p) pipe(10) | [print] | END # print run in a thread pipe(10) | t[print] | END # print run in a thread pipe(10) | p[print] | END # print run in a process
What makes this syntax good is that you can specify how many threads you want to spawn, by doing [function] * n where n is the number of threads.
pipe([1,2,3,4,5]) | [print] * 3 | END # print will run in a ThreadPool of size 3
Here is an example of requesting a list of urls in parallel
import requests (pipe(['google', 'twitter', 'yahoo', 'facebook', 'github']) | each(lambda name: 'http://' + name + '.com') | [requests.get] * 3 # !! `requests.get` runs in a ThreadPool of size 3 | each(lambda resp: (resp.url, resp.headers.get('Server'))) | list | END) # returns # [('http://www.google.com/', 'gws'), # ('https://twitter.com/', 'tsa_a'), # ('https://www.yahoo.com/', 'ATS'), # ('https://www.facebook.com/', None), # ('https://github.com/', 'GitHub.com')]
from syntax_sugar import is_a, has, to, step, drop 1 /is_a/ int # equivalent to `isinstance(1, int)` 1 /as_a/ str # "1" range(10) /has/ '__iter__' # equivalent to `hasattr(range(10), "__iter__")` 1 /to/ 10 # An iterator similar to `range(1, 11)`. # Python's nasty range() is right-exclusive. This is right-inclusive. 10 /to/ 1 # We can go backward. '0' /to/ '9' # We can also have a range of characters :) 1 /to/ 10 /step/ 2 # We can also specify step sizes. # Similar to `range(1, 11, 2)` 10 /to/ 1 /step/ 2 # Go backward. # Similar to `range(10, 0, -2)` 1 /to/ 10 /drop/ 5 # there is a `drop` functon which drop N items from the head # An iterator similar to [6, 7, 8, 9, 10]
/to/ has some advanced features
- lazy evaluation.
- support infinity.
- support product operation.
- support pipe.
from syntax_sugar import INF, take, each # CAUTION: this will infinitely print numbers for i in 1 /to/ INF: print(i) 1 /to/ INF /take/ 5 /as_a/ list # there is a `take` functon which is similar to itertools.islice # return [1, 2, 3, 4, 5] 1 /to/ ... /take/ 5 /as_a/ list # ... is equivalent to INF 0 /to/ -INF /step/ 2 /take/ 5 /as_a/ list # also works with negative infinity. # return [0, -2, -4, -6, -8] (1 /to/ 3) * (4 /to/ 6) /as_a/ list # all combinations of [1..3] * [4..6] # return [(1, 4), (1, 5), (1, 6), (2, 4), (2, 5), (2, 6), (3, 4), (3, 5), (3, 6)] 1 /to/ 10 /take/ 5 | each(lambda x: x **2) | END # These infix functions can also be piped. # [1, 4, 9, 16, 25]
Make your own infix function, so you can append multiple items to a list in one line.
from syntax_sugar import infix @infix def push(lst, x): lst.append(x) return lst [] /push/ 1 /push/ 2 /push/ 3 # returns [1,2,3]
You can also do
def push(lst, x): lst.append(x) return lst ipush = push /as_a/ infix [] /ipush/ 1 /ipush/ 2 /ipush/ 3 # returns [1,2,3]
In math, (f * g) (x) = f(g(x)). This is called function composition.
# lmap equivalent to `list(map(...))` lmap = compose(list, map) lmap(lambda x: x ** 2, range(10))
Let's say we want to represent f * g * h in a program, i.e. fn(x) = f(g(h(x)))
f = lambda x: x**2 + 1 g = lambda x: 2*x - 1 h = lambda x: -2 * x**3 + 3 fn = compose(f, g, h) fn(5) # 245026
or you can do
f = composable(lambda x: x**2 + 1) g = composable(lambda x: 2*x - 1) h = composable(lambda x: -2 * x**3 + 3) fn = f * g * h fn(5) # 245026
Sometimes you may prefer the decorator way.
# make your own composable functions @composable def add2(x): return x + 2 @composable def mul3(x): return x * 3 @composable def pow2(x): return x ** 2 fn = add2 * mul3 * pow2 # equivalent to `add2(mul3(pow2(n)))` fn(5) # returns 5^2 * 3 + 2 = 77
More receipes: https://github.com/czheo/syntax_sugar_python/tree/master/recipes