foliantcontrib.utils.chapters 1.0.4
Utils for chapters
License: MIT

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# Chapters utils

This module contains utils which make work with Foliant chapter lists easier.

## Installation

To use functions and classes from this module, install it with command

```bash
pip3 install foliantcontrib.utils.chapters
```

## Usage

Right now this module offers only one useful class, called `Chapters`. To start using it, import it:

```python
>>> from foliant.contrib.chapters import Chapters

```

Let's assume we have the following list of chapters specified in foliant.yml:

```yml
chapters:
    - introduction.md
    - Overview:
        - The Problem: problem.md
        - Requirements: req.md
        - Quick Start:
            - qs/installation.md
            - qs/first_steps.md
            - qs/advanced_usage.md
    - Specifications:
        - specs/core.md
        - specs/classes.md
```

If we want to interact wit this list of chapters, we will probably need path to Markdown-files in the proper order. That's exactly what the `Chapters` class offers. Let's translate this chapter list into Python and give it to the `Chapters` class:

```python
>>> chapters_list = ['introduction.md',{'Overview': [{'The Problem': 'problem.md'},{'Requirements': 'req.md'},{'Quick Start': ['qs/installation.md','qs/first_steps.md','qs/advanced_usage.md']}]},{'Specifications': ['specs/core.md', 'specs/classes.md']}]
>>> chapters = Chapters(chapters_list)

```

Optionally you can specify paths to your working and src dirs, those will be needed for the proper work of some methods:

```python
>>> chapters = Chapters(chapters_list, working_dir='__folianttmp__', src_dir='src')

```

But the recommended much easier option for initializing the Chapter class is by using `from_config` method:

```python
chapters = Chapters.from_config(config)
```

where config is your parsed foliant config dictionary.

### The **flat** property

The `flat` property of the `Chapters` class contains the list of chapter filenames in the correct order, with all the original hierarchy neatly flattened.

```python
>>> for chapter in chapters.flat:
...     print(chapter)
introduction.md
problem.md
req.md
qs/installation.md
qs/first_steps.md
qs/advanced_usage.md
specs/core.md
specs/classes.md

```

### The **paths** method

Usually when we work with chapters, we need not just ther names, as they stated in foliant.yml, but the paths to the actual files.

This is the work of the `paths` method, which accepts one argument: root of the markdown-files directory (usually `src` or `__folianttmp__`).

This method returns a generator, which yields `PosixPath` objects to each chapter in the proper order

```python
>>> for path in chapters.paths('src'):
...     print(repr(path))
PosixPath('src/introduction.md')
PosixPath('src/problem.md')
PosixPath('src/req.md')
PosixPath('src/qs/installation.md')
PosixPath('src/qs/first_steps.md')
PosixPath('src/qs/advanced_usage.md')
PosixPath('src/specs/core.md')
PosixPath('src/specs/classes.md')

```

### The **get_chapter_title** method

Method tries to find the chapter by its path in the chapter list and returns its MkDocs-style title, if it was defined in the chapter list.

Let's return to the example chapter list from the **Usage** section:

```yml
chapters:
    - introduction.md
    - Overview:
        - The Problem: problem.md
        - Requirements: req.md
        - Quick Start:
            - qs/installation.md
            - qs/first_steps.md
            - qs/advanced_usage.md
    - Specifications:
        - specs/core.md
        - specs/classes.md
```

If we try to find the title of the `req.md` chapter:

```python
>>> chapters.get_chapter_title('req.md')
'Requirements'

```

We get the title `'Requirements'`, which was defined in the config. On the other hand, if we try to get the title of a chapter `qs/first_steps.md`:

```python
>>> chapters.get_chapter_title('qs/first_steps.md')
''

```

We will get an empty string, because the title for this chapter was not defined in the config.

## Alternative usage

You can also use the `Chapters` object as if it was list:

```python
>>> chapters[0]
'introduction.md'
>>> 'req.md' in chapters
True
>>> for chapter in chapters:
...     print(chapter)
...     break
introduction.md

```

Original chapters list is available in the `chapters` property:

```python
>>> chapters.chapters
['introduction.md', {'Overview': [{'The Problem': 'problem.md'}, {'Requirements': 'req.md'}, {'Quick Start': ['qs/installation.md', 'qs/first_steps.md', 'qs/advanced_usage.md']}]}, {'Specifications': ['specs/core.md', 'specs/classes.md']}]

```

You can redefine your chapters on the fly:

```python
>>> chapters.chapters = ['one.md', {'two': 'three.md'}]
>>> for chapter in chapters:
...     print(chapter)
one.md
three.md

```