Discourse Placeholder Forms theme component


This theme component will let you build dynamic documentation, by creating a form that replaces any occurrence of a =PATTERN= in your post with the value from a text or selectable input field.

:link: Repository Link

:link: Preview on Theme Creator


[wrap=placeholder key=NAME description="Your name"][/wrap]
[wrap=placeholder key=COUNTRY default=US defaults=FR,DE,US,CN,AU,CA][/wrap]

Your email: =NAME=-=COUNTRY=@example.com

This will result in:

This is used in mailing list

Your email: =ZNAME=-=ZCOUNTRY=@example.com

As seen above, text inside the wrapper will be used as a long description.

[wrap=placeholder key=NAME description="Your name"]
This is used in mailing list

Available keys

  • key: The key that should be replaced in your post
  • default/defaults: default value(s)
  • description: a placeholder text for the input


# create a new plugin
rails g plugin =PLUGIN_NAME=
cd plugins/=PLUGIN_NAME=

We use it to create runbooks, howtos and reusable templates (it will work in code blocks). Please share your use cases!


The big issue with math handling like this, is that you need to eval() and eval is unsafe, so you need to use some lib which provide a safe eval with a limited subset of the real eval. I’m unsure we want all this complexity for such a rare case.


I tried ! and that would be a neat composer-preview-redux-in-OP kind of thing but… :pensive: I must be missing something, if I understand correctly the Reply Template component takes the raw and looks for “replacers”, but the Placeholder Forms component decorates the cooked?

What I’m trying to do is ease my users into adding some quizz Q&As in a topic, with minimal technical friction, clicks or even key strokes, :heavy-sigh: :roll_eyes:

[wrap=placeholder key="question" description="question"][/wrap]
[wrap=placeholder key="réponse" description="réponse"][/wrap]

[wrap=template key="template-spoiler" action="reply" tagsList="#qui, #quand, #où, #comment"]

## Question
### Réponse
*Étiquette(s) ?*

which gives

so far so good, but unfortunately, the placeholders =question= and =réponse= are kept in the composer when hitting the template button

Yes I’m not sure what I was thinking when I wrote this… I probably had a different use case in mind, but can’t remember.

It can’t work this way for sure. I will think a little bit about this… Both theme components were experiments at the time and might deserve better treatment as people have been using it quite frequently.


Thank you !

happy lets go GIF by Shalita Grant

1 Like

:grin: I don’t know what’s cookin’ in the chef kitchen, but as I usually stuff myself with pistachios or whatnot while waiting, I managed to make it work (for my specific use of course as I’ve almost no idea of what I’m doing, but hey… :sweat_smile: )


Ideally I would like to be able to let admin define their own replacers, but eval is risky (and not even possible with a secure csp) so I’m not sure how I could achieve this…


First of all - great and really helpful theme component.

But I think I found a bug. If I use a placeholder in a code snippet, that contains backticks (`), it is not working. An example is a SQL code snippet:

            id FROM (
                    id FROM `=TABLENAME=`
                ORDER BY
                    id DESC
                LIMIT 20
) subquery);

TABLENAME gets never replaced (if there is a TABLENAME placeholder).