Introducing a Wiki Like Input Format

I'm no developer, so I don't understand/know what exactly you need, but it might help:

Do you know the Creole project? http://www.wikicreole.org/
They created a wiki syntax:

Creole is a common wiki markup language to be used across different wikis. It's not replacing existing markup but instead enabling wiki users to transfer content seamlessly across wikis, and for novice users to contribute more easily

Maybe you could use this?

I've just started building a Wiki for my client and pretty surprised how little is available in Drupal for this. I have started piecing things together with Custom Filter (which seems to work well); but my client is suggesting (and rightfully so) that no one in this day and age uses markup language we all use wysiwyg editors (i wish i worked with same people she works with since my work mates still insist on VI as their plain text email editor.. lol.. but i digress)...

.. so my point being that i think 2 parts to this are required.. both a defined set of Wiki markup commands implemented as a filter; but also toolbar integration of these in standard wysiwyg editors (ideally toolbars were managed by the wysiwyg module and therefore not required to be done for each js editor out there.. but doubt we have gotten to that point yet).

one other bit to add to this is that my client's site is OG based.. and therefor some amount of OG aware knowledge is required by the filters.

For Example:

i use OG, Custom Filters, Wikitools and Pathauto modules

OG - gives me communal access to a node type ("wiki"); i consider this defining rule #1 for a wiki
Wikitools gives me the ability to pre-insert links into text and when a user selects the link, if node doesn't exist, they are presented with option to create - defining wiki rule #2

all the rest is usability..

custom filter lets me add this in a page [.[.[.Title of My Page.].].] (no . just used so not filtered)

and it creates this link in my document: /wiki/title-of-my-page?gids[]=142 where 142 is the gid of current group - wikitools doesn't mind the ?gids[]=142 and std OG ensures this wiki post belongs to my group.

and pathauto setting for wiki pages of: wiki/[title-raw]-[og-id] so that i don't have issues when each group tries to make a page called "Page 2"

not sure all the bits i have missing; but i think something that creates/manges breadcrumbs is main missing piece and, of course, toolbar icons to access things like wikilinks insertion.

Anyway, I've stopped its development because PEARWiki with WikiCreole does the job. I don't believe in reinventing the wheel, and that's the very reason I use Drupal instead of developing my own CMS.

https://www.drupal.org/project/simplewiki

Worked like a charm - took 2 mins to install and configure

Installing SimpleWiki

1. Download and extract the module to your sites/all/modules or wherever you are storing modules.
2. Enable the module
3. Create a new input format and select SimpleWiki as a filter
4. Optionally turn on autotoc on the filter settings page

If you want, you can then create a wiki content type - or when you create a page, you can submit any content type as a wiki.