efdba79ad1
New templates variables can be added by giving variable-value pairs as a
second return value of the global function `Doc`.
Example:
function Doc (body, meta, vars)
vars.date = vars.date or os.date '%B %e, %Y'
return body, vars
end
Closes: #6731
1.6 KiB
| author | date | title | |
|---|---|---|---|
|
November 21, 2021 | Creating Custom Pandoc Writers in Lua |
Introduction
If you need to render a format not already handled by pandoc, or you want to change how pandoc renders a format, you can create a custom writer using the Lua language. Pandoc has a built-in Lua interpreter, so you needn't install any additional software to do this.
A custom writer is a Lua file that defines functions for rendering each element of a pandoc AST.
For example,
function Para(s)
return "<paragraph>" .. s .. "</paragraph>"
end
The best way to go about creating a custom writer is to modify the example that comes with pandoc. To get the example, you can do
pandoc --print-default-data-file sample.lua > sample.lua
A custom HTML writer
sample.lua is a full-features HTML writer, with explanatory
comments. To use it, just use the path to the custom writer as
the writer name:
pandoc -t sample.lua myfile.md
sample.lua defines all the functions needed by any custom
writer, so you can design your own custom writer by modifying
the functions in sample.lua according to your needs.
Template variables
New template variables can be added, or existing ones
modified, by returning a second value from function Doc.
For example, the following will add the current date in
variable date, unless date is already defined as either a
metadata value or a variable:
function Doc (body, meta, vars)
vars.date = vars.date or meta.data or os.date '%B %e, %Y'
return body, vars
end