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| -rw-r--r-- | bot/resources/tags/type-hint.md | 19 |
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diff --git a/bot/resources/tags/type-hint.md b/bot/resources/tags/type-hint.md new file mode 100644 index 000000000..f4a12f125 --- /dev/null +++ b/bot/resources/tags/type-hint.md @@ -0,0 +1,19 @@ +**Type Hints** + +A type hint indicates what type a variable is expected to be. +```python +def add(a: int, b: int) -> int: + return a + b +``` +The type hints indicate that for our `add` function the parameters `a` and `b` should be integers, and the function should return an integer when called. + +It's important to note these are just hints and are not enforced at runtime. + +```python +add("hello ", "world") +``` +The above code won't error even though it doesn't follow the function's type hints; the two strings will be concatenated as normal. + +Third party tools like [mypy](https://mypy.readthedocs.io/en/stable/introduction.html) can validate your code to ensure it is type hinted correctly. This can help you identify potentially buggy code, for example it would error on the second example as our `add` function is not intended to concatenate strings. + +[mypy's documentation](https://mypy.readthedocs.io/en/stable/builtin_types.html) contains useful information on type hinting, and for more information check out [this documentation page](https://typing.readthedocs.io/en/latest/index.html). |