MacroPy is an implementation of Syntactic Macros in the Python Programming Language. MacroPy provides a mechanism for user-defined functions (macros) to perform transformations on the abstract syntax tree (AST) of a Python program at import time. This is an easy way to enhance the semantics of a Python program in ways which are otherwise impossible, for example providing an extremely concise way of declaring classes.
MacroPy allows you to create constructs which are impossible to have in normal python code, such as:
with trace:
sum([x + 5 for x in range(3)])
# sum([x + 5 for x in range(3)])
# range(3) -> [0, 1, 2]
# x + 5 -> 5
# x + 5 -> 6
# x + 5 -> 7
# [x + 5 for x in range(3)] -> [5, 6, 7]
# sum([x + 5 for x in range(3)]) -> 18print(list(map(f[_[0]], ['omg', 'wtf', 'bbq'])))
# ['o', 'w', 'b']
print(list(reduce(f[_ + _], ['omg', 'wtf', 'bbq'])))
# 'omgwtfbbq@case
class Point(x, y): pass
p = Point(1, 2)
print str(p) #Point(1, 2)
print p.x #1
print p.y #2
print Point(1, 2) == Point(1, 2) # Trueand more! See the docs at http://macropy3.readthedocs.io/en/latest/.
MacroPy3 is tested to run on CPython 3.4 or newer and PyPy 3.5. I has no current support for Jython. MacroPy3 is also available on PyPI.
Just execute a:
$ pip install macropy3if you want to use macros that require external libraries in order to
work, you can automatically install those dependencies by installing
one of the pinq or pyxl extras like this:
$ pip install macropy3[pinq,pyxl]then have a look at the docs at http://macropy3.readthedocs.io/en/latest/.
We're open to contributions, so send us your ideas/questions/issues/pull-requests and we'll do our best to accommodate you! You can ask questions on the Google Group and on the Gitter channel or file bugs on thee issues page.
MacroPy was initially created as a final project for the MIT class 6.945: Adventures in Advanced Symbolic Programming, taught by Gerald Jay Sussman and Pavel Panchekha. Inspiration was taken from project such as Scala Macros, Karnickel and Pyxl.
The MIT License (MIT)
Copyright (c) 2013-2018, Li Haoyi, Justin Holmgren, Alberto Berti and all the other contributors
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
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