Header Configuration

When weaveing a markdown document, you use YAML header to provide additional metadata and configuration options. A YAML header should be in the beginning of the input document delimited with ---.

Warning

YAML header configuration is only supported when weaveing markdown or Noweb syntax documents.

Document Metadata

You can set additional document metadata in YAML header. When weaveing to Julia markdown documents to HTML or PDF, Weave respects the following metadata specification:

title
author
date

An example:

---
title : Header Example
author : Shuhei Kadowaki
date: 16th May 2020
---

Note

You can also have other metadata, but they won't appear in the resulting HTML and PDF. If you weave to Julia markdown to GitHub/Hugo markdown, all the metadata will be preserved.

Dynamic Metadata

The metadata can be given "dynamically"; if you have inline code within YAML header, they will be evaluated after evaluating all the chunks and replaced with the results.

The example document below will set date metadata dynamically. Note that Date is available since the chunk is evaluated first.

 ---
 title : Header Example
 author : Shuhei Kadowaki
 date: `j import Dates; Dates.Date(Dates.now())`
 ---

 ```julia; echo = false
 using Dates
 ```

Configuration Options

Each of keyword arguments of weave can be set in the YAML header under options field. You can also set Chunks Options there that will be applied globally.

The example below sets out_path and doctype options and overwrites term and wrap chunk options:

---
title : Header Example
author : Shuhei Kadowaki
date: 16th May 2020
weave_options:
  out_path: relative/path/to/this/document
  doctype: github
  term: true
  wrap: false
---

Note

configurations specified within the YAML header have higher precedence than those specified via weave keyword arguments
chunk options specified within each chunk have higher precedence than the global global chunk options specified within the YAML header

Warning

As opposed to metadata, most of those configuration options can't be given dynamically (i.e. can't be via inline code), since they are needed for evaluation of chunks themselves. But some configuration options that are needed "formatting" document can still be given dynamically:

template
css
highlight_theme
pandoc_options
latex_cmd
keep_unicode

Format Specific Options

The header configurations can be format specific. Here is how to set different out_path for md2html and md2pdf and set fig_ext globally:

---
weave_options:
  md2html:
    out_path : html
  md2pdf:
    out_path : pdf
  fig_ext : .png
---