Allow using the filter without quarto

CHANGELOG.md

@@ -1,3 +1,10 @@
+# quarto-d2 1.2.0
+
+## NEW FUNCTIONALITY
+
+- Allow using the filter as a simple pandoc filter. This allows using the filter with other
+  document formats such as Rmarkdown.
+
 # quarto-d2 1.1.0
 
 ## NEW FUNCTIONALITY

README.md

@@ -16,24 +16,6 @@ Main features:
 This extension was inspired by
 [`ram02z/d2-filter`](https://github.com/ram02z/d2-filter).
 
-## Installation
-
-### Prerequisites
-
-Ensure that you have [D2](https://d2lang.com/tour/install) installed on
-your system.
-
-### Install
-
-Run the following command to add this extension to your current project:
-
-``` bash
-quarto add data-intuitive/quarto-d2
-```
-
-This will install the extension under the `_extensions` subdirectory. If
-you’re using version control, you will want to check in this directory.
-
 ## Example
 
 <div>
@@ -89,11 +71,39 @@ user -> network.portal.UI: access {
 
 </div>
 
+## Prerequisites
+
+Ensure that you have [D2](https://d2lang.com/tour/install) installed on
+your system.
+
 ## Usage
 
-To use the d2 filter, add the d2 filter to your quarto document. Next,
-add the `.d2` class to any code blocks containing D2 diagram code. Here
-is a basic example:
+The filter allows rendering D2 diagrams directly within your markdown
+documents.
+
+### Plain pandoc
+
+If you are using plain pandoc, you can use the `d2` filter by specifying
+it on the command line:
+
+``` bash
+pandoc --lua-filter d2.lua ...
+```
+
+### Quarto
+
+Install this filter as an extension with:
+
+``` bash
+quarto add data-intuitive/quarto-d2
+```
+
+This will install the extension under the `_extensions` subdirectory. If
+you’re using version control, you will want to check in this directory.
+
+By adding d2 to the list of filters in the YAML headers, you can use the
+`.d2` code block to render D2 diagrams directly within your markdown
+documents.
 
 ```` markdown
 ---
@@ -107,11 +117,17 @@ x -> y
 ```
 ````
 
-With this setup, the `d2` filter will process any code blocks with the
-`.d2` class, applying the attributes you specify.
+### RMarkdown
+
+Use `pandoc_args` to add the `d2` filter.
 
-That’s it! Now you know how to use the `d2` filter to generate diagrams
-in your quarto documents.
+``` yaml
+---
+output:
+  html_document:
+    pandoc_args: ['--lua-filter=d2.lua']
+---
+```
 
 ## Attributes
 
@@ -223,3 +239,8 @@ y {
 x -> y -> z
 ```
 ````
+
+## License
+
+This extension is distributed under the GPL-3 license, see file
+[`LICENSE`](LICENSE) for details.

README.qmd

@@ -17,24 +17,6 @@ Main features:
 
 This extension was inspired by [`ram02z/d2-filter`](https://github.com/ram02z/d2-filter).
 
-## Installation
-
-### Prerequisites
-
-Ensure that you have [D2](https://d2lang.com/tour/install) installed on your system.
-
-### Install
-
-Run the following command to add this extension to your current project:
-
-``` bash
-quarto add data-intuitive/quarto-d2
-```
-
-This will install the extension under the `_extensions` subdirectory.
-If you're using version control, you will want to check in this directory.
-
-
 
 ## Example
 
@@ -87,10 +69,37 @@ user -> network.portal.UI: access {
 ```
 
 
+## Prerequisites
+
+Ensure that you have [D2](https://d2lang.com/tour/install) installed on your system.
+
+
 ## Usage
 
-To use the d2 filter, add the d2 filter to your quarto document. Next, add the `.d2` class to any code blocks containing D2 diagram code. Here is a basic example:
+The filter allows rendering D2 diagrams directly within your markdown documents.
+
+### Plain pandoc
 
+If you are using plain pandoc, you can use the `d2` filter by specifying it on the command line:
+
+```bash
+pandoc --lua-filter d2.lua ...
+```
+
+### Quarto
+
+
+Install this filter as an extension with:
+
+``` bash
+quarto add data-intuitive/quarto-d2
+```
+
+This will install the extension under the `_extensions` subdirectory.
+If you're using version control, you will want to check in this directory.
+
+By adding d2 to the list of filters in the YAML headers, you can use the `.d2` code block to
+render D2 diagrams directly within your markdown documents.
 
 ````markdown
 ---
@@ -104,9 +113,17 @@ x -> y
 ```
 ````
 
-With this setup, the `d2` filter will process any code blocks with the `.d2` class, applying the attributes you specify.
+### RMarkdown
 
-That's it! Now you know how to use the `d2` filter to generate diagrams in your quarto documents.
+Use `pandoc_args` to add the `d2` filter.
+
+```yaml
+---
+output:
+  html_document:
+    pandoc_args: ['--lua-filter=d2.lua']
+---
+```
 
 ## Attributes
 
@@ -191,3 +208,7 @@ y {
 x -> y -> z
 ```
 ````
+
+## License
+
+This extension is distributed under the GPL-3 license, see file [`LICENSE`](LICENSE) for details.

_extensions/d2/d2.lua

@@ -1,3 +1,6 @@
+-- The filter uses walk, which was added in Pandoc 2.17
+PANDOC_VERSION:must_be_at_least '2.17'
+
 -- Enum for D2Theme
 local D2Theme = {
   NeutralDefault = 0,
@@ -196,6 +199,9 @@ local function render_graph(globalOptions)
               print("Error: Unsupported format")
               return nil
             end
+          else
+            print("Error: Unsupported embed_mode")
+            return nil
           end
         end
       end)

d2.lua

@@ -0,0 +1 @@
+_extensions/d2/d2.lua