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Commit c053100

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Update README.md (#8)
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‎README.md‎

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@@ -23,7 +23,7 @@ __Table of Contents__
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* [Function Composition](#function-composition)
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* [Continuation (TODO)](#continuation-todo)
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* [Point-Free Style (TODO)](#point-free-style-todo)
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* [Predicate (TODO)](#predicate-todo)
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* [Predicate](#predicate)
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* [Contracts (TODO)](#contracts-todo)
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* [Category (TODO)](#category-todo)
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* [Value (TODO)](#value-todo)
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Points-free function definitions look just like normal assignments without `def` or `lambda`.
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## Predicate (TODO)
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A predicate is a function that returns true or false for a given value. A common use of a predicate is as the callback for array filter.
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## Predicate
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A predicate is a function that returns true or false for a given value.
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So, basically a predicate is an alias for `Callable[[_ValueType], bool]`.
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It is very useful when working with `if`, `all`, `any`, etc.
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```python
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# TODO
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>>> def is_long(item: str) -> bool:
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... return len(item) > 3
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>>> assert all(is_long(item) for item in ['1234', 'abcd'])
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>>>
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```
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__Futher reading__
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* [Predicate logic](https://en.wikipedia.org/wiki/Predicate_functor_logic)
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* [`cond` docs](https://returns.readthedocs.io/en/latest/pages/pointfree.html#cond)
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## Contracts (TODO)
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A contract specifies the obligations and guarantees of the behavior from a function or expression at runtime. This acts as a set of rules that are expected from the input and output of a function or expression, and errors are generally reported whenever a contract is violated.

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