Show HN: Adding some syntactic sugar to Python(github.com)
github.com
Show HN: Adding some syntactic sugar to Python
https://github.com/czheo/syntax_sugar_python
9 comments
Julia has this kind of syntax (among others) for functions.
Related to your first idea, Fortran had statement functions, and it didn't go very well in the end.
What went wrong with them in Fortran?
With the usual method of declaring a function, it was easy to understand that 'x' was local to the function. Adding a second, more concise way to express functions led to confusion about the scope of 'x'.
Also, declaring types for the function and arguments (which is optional but has been strongly recommended since the Fortran '77 era) had to be done outside of the function, which again is unlike the usual syntax.
The only code I've ever seen statement functions used in dated from the 1970s.
Also, declaring types for the function and arguments (which is optional but has been strongly recommended since the Fortran '77 era) had to be done outside of the function, which again is unlike the usual syntax.
The only code I've ever seen statement functions used in dated from the 1970s.
Interesting. It's clear to me.
It looks a lot people who had some confusion with the scope of x in something like ...
It looks a lot people who had some confusion with the scope of x in something like ...
f(x) = x^2 + 1
f = lambda x: x^2 + 1
I think the Fortran problem was that f(x) = x^2 + 1 looks a lot like a normal statement, with only a subtle clue on the left hand side ("Hey, f isn't an array!...") Whereas in python, having 'lambda' is a bigger clue. Hard to know without trying it out on some test subjects. I don't think anyone really studied why the Fortran thing was a problem, but of course lots of people (including me) have guesses.
As for type hinting, Python 3 does support it: https://docs.python.org/3/library/typing.html but I think the better lesson to learn is that it can be hard to future-proof alternative syntax or syntactic sugar. I looked at the 3.X docs, and PEP 484 and 526, no mention of how this typing can work with lambdas, and no comment that it doesn't (!)
As for type hinting, Python 3 does support it: https://docs.python.org/3/library/typing.html but I think the better lesson to learn is that it can be hard to future-proof alternative syntax or syntactic sugar. I looked at the 3.X docs, and PEP 484 and 526, no mention of how this typing can work with lambdas, and no comment that it doesn't (!)
Mis-seeing it as an array makes a lot of sense for the f(x) syntax. That's probably even more true than it would be in a higher level language like python, because you're doing more stuff like that.
But for Python3 lambda type hints, I'm reading a definitive comment in PEP 3107 that it isn't supported [0]. Anecdotally, that also jives with what I'm seeing on the REPL.
But for Python3 lambda type hints, I'm reading a definitive comment in PEP 3107 that it isn't supported [0]. Anecdotally, that also jives with what I'm seeing on the REPL.
Python 3.6.0 (default, Jan 18 2017, 02:51:38)
[GCC 4.9.2] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import typing
>>> f = lambda x: int: x * 6
File "<stdin>", line 1
f = lambda x: int: x * 6
^
SyntaxError: invalid syntax
The docs pointed me to PEP 484 and 526, that's why I mentioned exactly what I'd looked at. PEP 3107 is not mentioned in https://docs.python.org/3/library/typing.html
Not trying to be pedantic here, just illustrating the point that this style of function can collide with future language developments, and confuse users.
Here's someone complaining that PEP 484 doesn't mention the impact of the new syntax on lambda: https://mail.python.org/pipermail/python-dev/2015-April/1397...
Not trying to be pedantic here, just illustrating the point that this style of function can collide with future language developments, and confuse users.
Here's someone complaining that PEP 484 doesn't mention the impact of the new syntax on lambda: https://mail.python.org/pipermail/python-dev/2015-April/1397...
This is a cool demonstration of how make some fundamental changes to Python by using operator overloading, but it feels fragile and very different from Python. At the end of the day, I'd think that if you want to program like this, you want a different language.
Yes, it's very anti-pythonic. I collected some ideas and created this lib just as an experimental toy to demonstrate some possibility.
Leaves me wondering if I'd be shooting off my little toe or my whole foot!
Might be fun to show pythonic equivalents for the ones that are relatively easy to make pythonic. You might discover some useful pythonic functions along the way.
Might be fun to show pythonic equivalents for the ones that are relatively easy to make pythonic. You might discover some useful pythonic functions along the way.
I feel so honored that this project was tweeted by Matz himself.
https://twitter.com/yukihiro_matz/status/823386626424328192
whoa - good job!
I like the threading / processes abstractions. I'll be watching this over time. Kudos.
The naming is odd, because the syntax hasn't changed, only the semantics of some operators have changed.
An example of syntactic sugar is list comprehensions. It's a new syntax for expressions using map, filter, etc. It's "new" syntax for something that can be described in terms of the "old" syntax without altering the semantics.
Given the name, I was expecting some kind of macro system or hacks to the Python parser.
An example of syntactic sugar is list comprehensions. It's a new syntax for expressions using map, filter, etc. It's "new" syntax for something that can be described in terms of the "old" syntax without altering the semantics.
Given the name, I was expecting some kind of macro system or hacks to the Python parser.
Yes, I agree with you. Strictly speaking, I was creating new semantics of the operators which looks like "new" syntax, to mimic "syntactic sugar". But I have no idea how to name this in a more understandable way.
On a similar note I wrote this over few days last week: https://github.com/adh/py-clos
What it severely lacks is readme that clearly states what it does with some realistic examples and is understandable by people who have no idea what CLOS is, so: It allows you to do function overloading which is resolved dynamically based on actual types of passed values or even values themselves. With the included (trivial) C extension it's only about 50% slower than Python method call, so in all for expected usecase it's faster than Visitor pattern not to mention more DRY.
What it severely lacks is readme that clearly states what it does with some realistic examples and is understandable by people who have no idea what CLOS is, so: It allows you to do function overloading which is resolved dynamically based on actual types of passed values or even values themselves. With the included (trivial) C extension it's only about 50% slower than Python method call, so in all for expected usecase it's faster than Visitor pattern not to mention more DRY.
Sounds kinda like Pyp http://opensource.imageworks.com/?p=pyp which I've been meaning to get more into, to replace shell foo.
That was always an interesting project. Too bad it's not maintained.
It's like the ugly baby of Python and OCaml
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But most of the other ideas are less intuitive than their native counterparts. For example, I think that the native form:
is clearer than: