Skip to content

README.md: rearrange first paragraph to be more friendly #4002

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
gvanrossum merged 9 commits into from
Sep 26, 2017
Merged

README.md: rearrange first paragraph to be more friendly #4002

Changes from 5 commits
Commits
Show all changes
9 commits
Select commit Hold shift + click to select a range
77938e0
README.md: rearrange first paragraph to be more friendly
elazarg Sep 25, 2017
43f3988
Demonstration for comments and new style annotations
elazarg Sep 25, 2017
998e4c3
Remove erroneous statement
elazarg Sep 25, 2017
932aa4d
Remove variable annotations. Change description of annotations
elazarg Sep 25, 2017
5422d17
move PEP-484 link and type comment; deep link for Python 2
elazarg Sep 26, 2017
8ed7f76
Remove mention of LXML
elazarg Sep 26, 2017
db8e6df
Fix type comment and give better example
elazarg Sep 26, 2017
e2b9b94
s/str/bool/
elazarg Sep 26, 2017
09c1055
Wrap long line.
gvanrossum Sep 26, 2017
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
26 changes: 13 additions & 13 deletions README.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -25,23 +25,14 @@ What is mypy?
-------------

Mypy is an optional static type checker for Python. You can add type
hints to your Python programs using the standard for type
annotations introduced in Python 3.5 ([PEP 484](https://www.python.org/dev/peps/pep-0484/)), and use mypy to
type check them statically. Find bugs in your programs without even
running them!

The type annotation standard has also been backported to earlier
Python 3.x versions. Mypy supports Python 3.3 and later.
XML based reports do not work on Python 3.3 and 3.4 on Windows.

For Python 2.7, you can add annotations as comments (this is also
specified in [PEP 484](https://www.python.org/dev/peps/pep-0484/)).
hints ([PEP 484](https://www.python.org/dev/peps/pep-0484/)) to your Python programs, and use mypy to type check them statically.

@ilevkivskyi ilevkivskyi Sep 26, 2017

Copy link
Copy Markdown
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Not super-important, but could you please make lines in your diff 79 chars?

@elazarg elazarg Sep 26, 2017

Copy link
Copy Markdown
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Sorry. I will try to keep it in mind.

Find bugs in your programs without even running them!

You can mix dynamic and static typing in your programs. You can always
fall back to dynamic typing when static typing is not convenient, such
as for legacy code.

Here is a small example to whet your appetite:
Here is a small example to whet your appetite (Python 3):

```python
from typing import Iterator
Expand All @@ -52,11 +43,20 @@ def fib(n: int) -> Iterator[int]:
yield a
a, b = b, a + b
```
See [the documentation](http://mypy.readthedocs.io/en/stable/introduction.html) for more examples.

For Python 2.7, the standard annotations are written as comments:
```python
def reverse(s):
# type: str -> str

@ilevkivskyi ilevkivskyi Sep 26, 2017

Copy link
Copy Markdown
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This should be # type: (str) -> str (note parentheses), otherwise it is syntax error in type comment.

return s[::-1]

@ilevkivskyi ilevkivskyi Sep 26, 2017

Copy link
Copy Markdown
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Maybe use a slightly less trivial example? Like is_palindrome(s) that returns s == s[::-1]?

@elazarg elazarg Sep 26, 2017

Copy link
Copy Markdown
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Nice! :)
I tried to find something like that and all I came up with was reverse :(

```

See [the documentation for Python 2 support](http://mypy.readthedocs.io/en/latest/python2.html).

Mypy is in development; some features are missing and there are bugs.
See 'Development status' below.


Requirements
------------

Expand Down