language	highlight-style
en	native

Formátítko 2.0

A python program based on pandoc and its python library panflute for converting from markdown to TeX and HTML with added fancy features like image processing, python-based macros and much more.

Requirements

This project requires panflute 2.3.0 that itself requires pandoc 3.0. If the version of pandoc doesn't match, very weird things can happen. ImageMagick and Inkscape are used for image processing. Nodejs is used for KaTeX.

Usage

usage: formatitko.py [-h] [-l IMG_LOOKUP_DIRS [IMG_LOOKUP_DIRS ...]] [-p IMG_PUBLIC_DIR] [-i IMG_WEB_PATH] [-w OUTPUT_HTML] [-t OUTPUT_TEX] input_filename

positional arguments:
  input_filename        The markdown file to process.

options:
  -h, --help            show this help message and exit
  -l IMG_LOOKUP_DIRS [IMG_LOOKUP_DIRS ...], --img-lookup-dirs IMG_LOOKUP_DIRS [IMG_LOOKUP_DIRS ...]
                        Image lookup directories. When processing images, the program will try to find the image in them first. Always looks for images in the same folder as the markdown
                        file. (default: [])
  -p IMG_PUBLIC_DIR, --img-public-dir IMG_PUBLIC_DIR
                        Directory to put processed images into. The program will not overwrite existing images. (default: public)
  -i IMG_WEB_PATH, --img-web-path IMG_WEB_PATH
                        Path where the processed images are available on the website. (default: /)
  -w OUTPUT_HTML, --output-html OUTPUT_HTML
                        The HTML file (for Web) to write into. (default: output.html)
  -t OUTPUT_TEX, --output-tex OUTPUT_TEX
                        The TEX file to write into. (default: output.tex)

Format

Formátítko uses all the default pandoc markdown extensions except for definition lists and citations. It also adds its own custom features.

Features

Hiding and showing elements based on flags

Flags can be set in the Front Matter or with python code. Then, elements with the if attribute will only be shown if the flag is set to True and elements with the ifn attribute will only be show if the flag is not set to True.

Example:

---
flags:
  foo: true
---
[This will be shown]{if=foo}

[This will not be shown]{if=bar}

[This will be shown]{ifn=bar}

Including other files

There are two ways of including files.

Importing

The first is importing, which only takes the state (defined commands, metadata, etc.) from the file and any content is omitted. This is useful for creating libraries of commands. The syntax is as follows:

[#test/empty.md]{}

The curly braces are required for pandoc to parse the import properly and should be left empty.

Partials

Partials are the very opposite of imports, they have their own context, which inherits everything from the context they're included in, but gets reset after the file ends.

:::{partial=test/empty.md} :::

If the untrusted attribute is set to True, the partial and all its children will not be able to define commands or run inline blocks (but it will be able to run commands defined in the parent). ^[Please don't trust this for any security though, we're playing with eval fire, this will never be secure.]

You can also import raw HTML and TeX if you set the type attribute of the partial to tex or html.

Groups

Groups are pieces of markdown with their own sandboxed context, in other words, inline partials. They function exactly the same as partials, namely can have their own front matter.

---
language: cs
---
OOOoo český mód

If you need to nest groups or have code blocks inside groups, you can increase the amount of backticks around the outer block:

```go
fmt.Pritln("owo")
```

Groups and partials are also enclosed in \begingroup and \endgroup in the output TeX.

Raw HTML and TeX ^[This is a pandoc feature]

If raw HTML or TeX is included in the markdown file, it will automagically pop out into the respective output file.

red text

\vskip1em

This has the advantage and disadvantage of being very "automagic", which means that for instance markdown inside HTML will still get interpreted as markdown. It is however very very unreliable, so in most cases, you should use explicit raw blocks with the unnamed attribute set to either html or tex. ^[Still a pandoc feature.]

<span style="color: red">red text</span>

Running python code

Formátítko allows you to run Python code directly from your MD file. Any python code block with the class run will be executed:

Context

You can access the current context using the ctx variable. The context provides read/write access to the FrontMatter metadata. The context has the following methods:

ctx.get_metadata(key: str, simple: bool=True, immediate: bool=False)

• key: The key of the metadatum you want to get. Separate child keys with dots: ctx.get_metadata("flags.foo")
• simple: Whether to use python's simple builtin types or panflute's MetaValues. MetaValues can contain formatted text, simple values loose all formatting.
• immediate: Only get metadatum from the current context, not from its parents.

ctx.set_metadata(key: str, value)

• key: The key of the metadatum you want to get. Separate child keys with dots: ctx.get_metadata("flags.foo")
• value: Any value you want to assign to the metadatum

ctx.unset_metadata(key: str)

Delete the metadatum in the current context and allow it to inherit the value from the parent context.

• key: The key of the metadatum you want to get. Separate child keys with dots: ctx.get_metadata("flags.foo")

Helper functions for flags exist which work the same as for metadata:

ctx.is_flag_set(flag: str) -> bool

ctx.set_flag(flag: str, val: bool)

ctx.unset_flag(flag: str)

Writing output

There are two modes of writing output, plaintext and element-based.

Plaintext mode uses the print(text: str) and println(text: str) functions, that append text to a buffer which is then interpreted as markdown input.

Element-based mode uses the appendChild(element: pf.Element) and appendChildren(*elements: List[pf.Element]) functions which allow you to append panflute elements to a list which is then again interpreted as input. The panflute library is available as pf.

When one of these functions is called, the mode is set and functions from the other mode cannot be called within the same block of code.

Examples:

---
title: Foo
---
```python {.run}
println("*wooo*")
println()
println("The title of this file is: " + ctx.get_metadata("title"))
```

appendChild(pf.Para(pf.Strong(pf.Str("foo"))))

Defining and running commands

Code blocks can be also saved and executed later. Defining is done using the define attribute:

Example:

print("foo")

If you try to define the same command twice, you will get an error. To redefine a command, use the define attribute instead of redefine.

Running defined commands

There are multiple ways of running commands. There is the shorthand way:

[!commandname]{}

Or using the c attribute on a span or a div:

[Some content]{c=commandname}

:::{c=commandname} Some content :::

To access the content or attributes of the div or span the command has been called on, the element variable is available, which contains the panflute representation of the element.

Example:

appendChild(element.content[int(element.attributes["i"])])

[Pick the third element from this span]{c=index i=2}

Direct metadata print

Metadata can be printed directly using a shorthand. The advantage of this is it keeps the formatting from the metadatum's definition

---
a:
  b: some text with **strong**
---
[$a.b]{}

Syntax highlighting

Formátítko uses pygments to highlight syntax in code blocks. To turn it off for a single block, don't specify a language or set the highlight attribute to False. You can also set the metadatum highlight to false in the FrontMatter to disable it in a given Group. To change the highlighting style, you have to set the highlight-style metadatum in the top-level document this is to prevent the need for many inline style definitions.

Examples:

print("cool")

./formatitko.py README.md

Language awareness

Formátítko is language aware, this means that the language metadatum is somewhat special. When set using the front matter, it is also popped out to TeX as a \languagexx macro. Currently supported values are cs and en for internal uses but can be set to anything.

NBSP

Formátítko automatically inserts no-break spaces according to its sorta smart rules. (See the whitespace.py file for more info) These rules depend on the chosen language. (cs has some additional rules)

To insert a literal no-break space, you can either insert the unicode no-break space or use the html escape.

Enforcing a breakable space is not as painless, you should insert a​ zero-width space beside the normal​ space.

Smart quotes

Quotes get automatically converted to the slanted ones according to the current language.

Examples:

---
language: cs
---
"Uvozovky se v českém testu píší 'jinak' než v angličtině."

"In Czech texts, quotes are written 'differently' than in English"

Math

Math blocks get automatically converted to HTML using $Ka\TeX$ and fall out unchanged into TeX output.

To make KaTeX as consistent with TeX as possible, the \begingroup and \endgroup that are produced by Groups are also emulated in the KaTeX environment, so macro definitions should be isolated as you expect.

Images

Figures

Pandoc's implicit figures are enabled, so images which are alone in a paragraph are automatically converted to figures:

{width=10em}

To prevent this, add a backslash at the end of the line with the image:

{width=10em}\

Image gathering

Images are automatically searched for in the directory where each markdown file is (including partials) and also in directories listed in the --lookup-dirs command line parameter. After processing, they're all put into the folder specified with --public-dir.

Image processing

Images are automatically processed so that they can be successfully used in both output formats. This includes generating multiple sizes and providing a srcset.

To customize this, the file-width, file-height, file-dpi, file-quality and no-srcset attributes are available. All but the last one should be integers.

Keep in mind that the processing tries to be as lazy as possible, so it never overwrites any files and if it finds the right format or resolution (only judging by the filenames) in the lookup directories it will just copy that. This means that any automatic attempts at conversion can be overridden by converting the file yourself, naming it accordingly and placing it either in the public or one of the lookup directories.

Working with the produced output

HTML

The HTML should be almost usable as-is. The styles for synstax-highlighting are added automatically. The styles for KaTeX however are not and should be added in your <head>^[This is taken directly from KaTeX's docs]:

<link rel='stylesheet' href='https://cdn.jsdelivr.net/npm/katex@0.16.4/dist/katex.min.css' integrity='sha384-vKruj+a13U8yHIkAyGgK1J3ArTLzrFGBbBc0tDp4ad/EyewESeXE/Iv67Aj8gKZ0' crossorigin='anonymous'>

Also the output HTML is not intended as a standalone file but should be included as part of a larger template. (That includes a doctype, other css, etc.)

TeX

The TeX output is not usable as is. Many of the elements are just converted to macros, which you have to define yourself. There is an example implementation in formatitko.tex, which uses LuaTeX and the ucwmac package, but you should customize it to your needs (and to the context in which the output is used).