pandoc-include

Pandoc filter to allow including files and headers in a document.

Features

• Include as raw blocks
• Indent and dedent included contents
• Partial include: Allow including only parts of the file using options
• Code include: Allow using !include in code blocks
• Unix style pathname
• Recursive include: It depends on include-entry header to work
• Yaml header Merging: When an included file has its header, it will be merged into the current header. If there's a conflict, the original header of the current file remains.
• Header include: Use !include-header file.yaml to include Yaml header from file.

TODO

• Write options to a tmp file and pass the filename by environment variable

Installation

Using pip

To install the latest published version:

pip install --user pandoc-include

To install the current (development) version hosted on the repository, use

pip install --upgrade --force --no-cache git+https://github.com/DCsunset/pandoc-include

To check the version currently installed:

pip show pandoc-include

Using Nix

pandoc-include is included in the Nixpkgs. Simply add the package to your NixOS config or use the following command:

# install in your profile
nix-env -iA nixpkgs.pandoc-include

# Or use it temporarily in a shell
nix-shell -p pandoc-include

Usage

Note: you should use pandoc with version greater than or equal to 2.17, which is the minimum version that is tested.

Command

To use this filter, add to pandoc command

pandoc input.md --filter pandoc-include -o output.pdf

Syntax

Each include statement has its own line and has the syntax:

!include somefolder/somefile

!include-header file.yaml

Or

$include somefolder/somefile

$include-header file.yaml

Each include statement must be in its own paragraph. That is, in its own line and separated by blank lines.

For code include, use !include statement in a code block:

```cpp
!include filename.cpp
```

The path can be either absolute or relative to the current file's directory. Besides, unix-style pathname can used. (If the include statement is used in an included file, then the path is absolute or relative to the included file itself.)

If there are special characters in the filename, use quotes:

!include "filename with space"
!include 'filename"with"quotes'

If the filename contains special sequences in markdown, use backquotes: (Note: this also applies to include statment in code blocks)

!include `__filename__`

The second syntax may lead to wrong highlighting when using a markdown editor. If it happens, use the first syntax. Also make sure that there are no circular includes.

The !include command also supports options:

!include`<key1>=<value1>, <key2>=<value2>` some_file

For example, to specify line ranges in options:

!include`startLine=1, endLine=10` some_file

Or to include snippets with enclosed delimiters:

!include`snippetStart="<!-- Start -->", snippetEnd="<!-- End -->"` some_file

Or including xml files transforming them with XSLT:

!include`format="markdown", xslt="xslt/api.xslt"` main_8h.xml

where <!-- Start --> and <!-- End --> are two strings occuring in some_file.

If multiple occurences of <!-- Start --> or <!-- End --> are in some_file, then pandoc-include will include all the blocks between the delimiters. If snippetEnd or snippetStart is not found or specified, it will include till the end or from the start.

Supported options:

Key	Value	Description
startLine	int	Start line of include (default: 1)
endLine	int	End line of include (default: number of the last line)
snippetStart	str	Start delimiter of a snippet
snippetEnd	str	End delimiter of a snippet
includeSnippetDelimiters	bool	Whether to include the delimiters (default: False)
incrementSection	int	Increment (or decrement) section levels of include
dedent	int	Remove n leading whitespaces of each line where possible (-1 means remove all)
format	str	The input format of the included file (see pandoc --list-input-formats). It will be automatically deduced from the path if not set. (Hint: extensions can also be enabled here)
raw	str	Include as raw block. The arg is the format (latex, html...)
xslt	str	XSLT file to use for transforming the given .xml file (This is intended to be used with Doxygen's xml output

Note: the values above are parsed as Python literals. So str should be quoted like 'xxx' or "xxx"; bool should be True or False.

Header options

---
include-entry: '<path>'
include-order: 'natural'
include-resources: '<path>[:<path>]'
rewrite-path: true
pandoc-options:
  - --filter=pandoc-include
  - <other options>
---

include-entry

The include-entry option is to make recursive includes work. Its value is a path relative to current working directory or absolute where the entry file (the initial file) locates. It should be placed in the entry file only, not in the included files. It is optional and the default include-entry value is ..

For example, to compile a file in current directory, no header is needed:

pandoc test.md --filter pandoc-include -o test.pdf

However, to compile a file not in current directory, like:

pandoc dir/test.md --filter pandoc-include -o test.pdf

The header should now be set to: include-entry: 'dir'.

include-order

The include-order options is to define the order of included files if the unix-style pathname matches multiple files. The default value is natural, which means using the natural order. Other possible values are alphabetical and default. The default means to keep the order returned by the Python glob module.

include-resources

The include-resources can be used to simplify relative paths of include statements by searching in the given paths for files with relative paths when otherwise not found.

Given following directory structure and pandoc command:

main.md
examples/
    hello-world.c
content/
    chapter1/
        chapter01.md
        image.png
    chapter2/
        chapter02.md
        image.png

$ pandoc --metadata include-resources=examples/ ... main.md

This will make it possible to have following include line in chapter01.md and chapter02.md

```cpp
!include hello-world.c
```

Instead of:

```cpp
!include ../../examples/hello-world.c
```

This is most useful if some resources, e.g. source code or Doxygen output, is located in an external directory structure.

rewrite-path

The rewrite-path option is a boolean value to configure whether the relative paths of images should be rewritten to paths relative to the root file. The default value is true.

For example, consider the following directory structure:

main.md
content/
  chapter01.md
  image.png

Suppose chapter01.md uses the image image.png. It should use ![Image](image.png) if rewrite-path is true, or ![Image](content/image.png) if rewrite-path is false.

pandoc-options

The pandoc-options option is a list to specify the pandoc options when recursively processing included files. By default, the included file will inherit the pandoc-options from its parent file, unless specified in its own file.

To make the recursive includes work, --filter=pandoc-include is necessary. The default value of pandoc-options is:

pandoc-options:
  - --filter=pandoc-include

Examples

File include

File include can be used to separate chapters into different files, or include some latex files:

---
title: Article
author: Author
toc: true
---

!include chapters/chap01.md

!include chapters/chap02.md

!include chapters/chap03.md

!include`raw="latex"` data/table.tex

Header include

For header include, it is useful to define a header template and include it in many files.

For example, in the header.yaml, we can define basic info:

name: xxx
school: yyy
email: zzz

In the main.md, we can extend the header:

---
title: Title
---

!include-header header.yaml

# Section

Body

The main.md then is equivalent to the follow markdown:

---
title: Title
name: xxx
school: yyy
email: zzz
---

# Section

Body

Environment Variables

The following environment variables can be set to change the default behaviour:

Key	Value	Description
PANDOC_INCLUDE_NOT_FOUND_ERROR	0 or 1	Emit an error if file not found (default: 0)

Development

To setup local dev environment, you can use python venv to create a virtual environment from requirements.txt.

Or if you use Nix, you can simply run nix develop.

Contributing

Contributions are welcome if you find any bugs or want to add some features. Please open an issue for discussion first if it's a big change (e.g. a new feature) or if you are uncertain about it.

Please follow Conventional Commits for your commit messages so that the changelog can be generated automatically.

Trouble Shooting

Command-line options

The pandoc command-line options are processed in order. If you want some options to be applied in included files, make sure the --filter pandoc-include option is specified before those options.

For example, use bibliography in the included files:

pandoc main.md --filter pandoc-include --citeproc --bibliography=ref.bib -o main.pdf

Executable not found

For some operating systems, the path may not be set correctly after installation. Make sure that the pandoc-include executable is put in the directory which is in the PATH environment.

License

MIT License