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Macros for Python: Quasiquotes, Case Classes, LINQ and more!

Project description

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MacroPy is an implementation of 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 Python code at module import time. This is an easy way to modify the semantics of a python program

Python like you’ve never seen before

MacroPy allows you to create constructs which are impossible to have in normal python code, such as:

Tracing

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)]) -> 18

Quick Lambdas

print map(f[_[0]], ['omg', 'wtf', 'bbq'])
# ['o', 'w', 'b']

print reduce(f[_ + _], ['omg', 'wtf', 'bbq'])
# 'omgwtfbbq

Case Classes

@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) # True

And more! All this runs perfectly on vanilla Python 3.5+ (an maybe on pypy, untested). For more details, see the GitHub page. or ask in the Gitter channel or the Google group .

Changelog

1.0.4.dev2 (2017-09-08)

  • Add MANIFEST.in;

1.0.4.dev1 (2017-09-08)

  • Updated the import machinery and macro detection to be compatible with Python 3.5+.

  • Removed support for Python 2, supporting it would require a way to manage differences at the ast level, but i don’t use Python2 anymore.

  • Added support for Python 3.5+ in the form of new call arguments form and new AsyncFunctionDef.

  • Basic scope analysis now available in the form of the @Scoped decorator, to be used in conjunction with @Walker.

1.0.3

  • Error messages are now raised at run-time rather than at import time, with other improvements (double stack traces, catchability).

  • @enum macro now has much better error messages

  • Improved error messages for mis-use of stub functions outside their related macro (e.g. the u, name, ast stubs for the q/hq macros)

  • Improved error messages for invalid case class signatures

  • Hygienic Quasiquotes now allow lexical capture of module objects

1.0.2

  • Removed unit test from PyPI distribution

1.0.1

  • Fixed a bug in ast_ctx_fixer

  • gen_sym() is now gen_sym(name="sym"), allowing you to override the base name

  • Implemented macropy.case_classes.enum macro

  • Implemented macropy.quick_lambda.lazy and macropy.quick_lambda.interned macros

Project details


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